Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Sat Jul 12 2008 03:08 PM |
Bertha Near Bermuda, Watching Wave East of the Lesser Antilles
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4:00 PM 14-July-2008 Update
The government of Bermuda has issued a Hurricane Watch. Recent reconnaissance mission has detected wind just below hurricane strength in a rain ban arcing around the southwest semi-circle. That rain band is expected to pass over the island over the next several hours. It is possible that Bertha will reach minimal hurricane strength.
John (typhoon_tip)
2:54 PM 14-July-2008 Update
Satellite estimates for 94L are at (SSD / t#s) are 2.0 now, which is probably enough to start considering it a candidate for a depression, possibly late tonight or more likely tomorrow only if it holds like this for a while.
2:20 PM 14-July-2008 Update
Bertha is due east of Bermuda right now, and the outer eye type feature is onshore causing issues there.
The wave east of the lesser Antilles (94L) has improved slowly during the day and may form into a depression sometime tomorrow or so if it persists. It still lacks a good organized flow and convection and Satellite Estimes (Dvorak T-Numbers) still do not suggest a depression (look for T numbers 2 or higher)
9:30 AM 14-July-2008 Update
Bertha is near the island of Bermuda, causing Tropical Storm conditions on the island right now. Bermuda is under a Tropical Storm Warning currently.
East of the Lesser Antilles, the wave (94L) is looking not quite so good this morning. It has moved away from the Intra Tropical Convergence Zone, and is starting to see some circulation, but the convection is not there.
That said, if it persists (it may not) it will likely form into a depression either late today or more likely tomorrow.
The lesser Antilles will want to watch this one. Because of lack of good initialization in models (IE, the UKMet doesn't develop this at all), any real prediction of future track or intensity of this system is pure speculation.
7:30 PM 13-July-2008 Update
Tropical Storm watches remain up for Bermuda, as Bertha slowly moves along.
Nothing too much new to report, 94L (Wave east of the islands) is having more model runs come in, which suggests that the Leeward Islands (And all of the Lesser Antilles) need to watch it.
It is fairly active, but not overly so, for mid July, and this system is likely the next depression.
If it stays organized overnight (it may fall apart), it could develop by or on Tuesday into a depression.
The low off Charleston has fallen apart today, and is not being watched anymore.
8:30 AM 13-July-2008 Update
Bertha has weakened to a Tropical Storm, and the eye that has been visible the last few days has disappeared. It will likely meander for a bit.
Two new things are worth watching this morning, first the wave in the Central Atlantic (further south and west from where Bertha formed) is worth watching over the next several days to see if it forms, it is more likely this would track further westward if shear or dry air does not keep it from development.
The Windward islands in the Caribbean will want to watch this one, actually all the Lesser Antilles. Track wise a generally westward movement should occur. Again, it will be important to watch over the next several days.
East Atlantic (94L) Wave Chances of Development in the next 24 hours
Code:
(forget it) 0 1 2 3 4 5 6 7 8 9 10 (sure thing)
[------*-------------]
{{StormLinks|94L|94|3|2008|2|94L}}
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Also southeast of Charleston, SC is a low pressure area that will have to be watched. Right now Shear would prevent any development, but if that lessens it is possible for something to form there.
Charleston Low Developmetn Chances in Next 24 hours
Code:
(forget it) 0 1 2 3 4 5 6 7 8 9 10 (sure thing)
[---*----------------]
More to come on both soon.
Original Update
Hurricane Bertha has been stationary, about 220 miles to the south southeast of Bermuda, for the past few hours. She has a nice circular presentation again as the shearing influence in the northwest quadrant has ceased. Sustained winds are now 85mph with gusts to 105mph and the central pressure, as reported by the hurricane hunters is 976MB. There is likely to be very little motion for the next day or two - Bertha is stuck in an area of negligible steering currents as the trough to her northwest is not expected to 'capture' the hurricane and move her off to the northeast in the open Atlantic. A stronger trough well to the northwest of Bertha, currently extending from the Great Lakes to Texas, is moving slowly eastward, but there is still some uncertainty as to whether that trough will be strong enough to move Bertha away from Bermuda early next week.
High pressure is likely to build to the north of Bertha as the first trough moves off to the northeast of the storm. Under the influence of that buildup in higher pressure to the north, Bertha's movement will be erratic - and slow for a few days, with a general northerly drift expected. Any additional jog to the west of north would bring the hurricane closer to Bermuda, and the Tropical Storm Watch for Bermuda has now been elevated to a Tropical Storm Warning.
Regarding intensity, Bertha is not likely to get any stronger - and in fact she has a much better chance of weakening. With the expectation for just a slow meander, I'm a bit surprised that the concept of 'upwelling' has not yet been mentioned in the intensity forecast. When a storm remains relatively stationary for an extended period of time, deeper - and colder - water is churned up in and around the eye of the storm and the system will slowly weaken as the SSTs cool down.
(Well, scratch that - Dr Avila just mentioned the likelyhood of upwelling in the latest NHC Discussion bulletin.)
In addition to Bertha, an active tropical wave near 10N 50W at 12/15Z is moving westward into an area of lighter wind shear.
ED
Update - Saturday 07/12 11:30AM ET
Tropical Storm Warning is now in effect for the island of Bermuda.
Bertha is a ragged looking tropical cyclone. Like much of yesterday, Bertha is composed of a massive eye and outer band of moderate convection, with a remnant inner eye and occasional attempts at eye-wall rattling around inside. Her movement has been virtually stationary over the last 6 hours. Dvorak numbers have eased by 5kts and her intensity is being officiated at 75kts. The stationary nature of Bertha may mean that SSTs are beginning to cool due to upwelling, and if so this would also begin to contribute to weakening.
The forecast essentially is unchanged. There seems to somewhat better agreement among the models that she will stagnate for another 2 days, but then slowly...ever so slowly begin to move north and eventually northeast or east.
John (typhoon_tip)
Event Related Links
{{StormCarib}}
{{BermudaNews}}
Use this link to monitor the current weather conditions at Hamilton, Bermuda:
Bermuda Weather
{{StormLinks|Bertha|02|2|2008|1|Bertha}}
{{StormLinks|94L|94|3|2008|2|94L}}
| Unregistered User |
| (Unregistered) |
| Sat Jul 12 2008 10:18 PM |
Re: Bertha Stalls SSE of Bermuda
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Well i see that Bertha is finally making that northward turn now. Bertha has been an interesting storm and has given us all a suprise so far, It's kinda like tuning into a soap opera "stay tuned for tomorrow's episode....." Might be we may see this all year round.
| typhoon_tip |
| (Meteorologist) |
| Sat Jul 12 2008 11:37 PM |
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Re: Bertha Stalls SSE of Bermuda
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I don't think so just yet... She's been essentially motionless during the day; NHC confirms this observation in their 5pm update. If anything, to these eyes she's wobble SW a tiny bit.
John
| stormchazer |
| (Storm Tracker) |
| Sun Jul 13 2008 10:23 AM |
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Re: Bertha Stalls SSE of Bermuda
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According to NRL, 94L has now joined the party. Invest 94L
| HanKFranK |
| (User) |
| Sun Jul 13 2008 01:41 PM |
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trifecta
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no reason to believe any one of the features currently trying to develop and accompany bertha aren't going to give it a try. the eastpac has been coughing up one storm after another since boris... and the shear in much of the atlantic basin has been ridiculously low for much of july (especially in the mdr east of the islands).
case by case..
current active storm bertha is unlikely to stop being bertha anytime soon. every one of the forecast models maintains the storm through d5... aside from other development confusing the evolution further, the current nhc track appears to have enough blanket support to be believable. expect an erratic track that eventually ends in a surge to the northeast... next weekend perhaps. bertha is an already a long-lived system for july. i haven't exhaustively researched what the record for that is, but i'm fairly sure bertha will have it when all is said and done.
94L is likely our next named storm. shouldn't be a lightning fast development, but i'd be surprised if it wasn't td 3 by tuesday. the embryo for this storm is the diffuse area of itcz vorticity near 9/38. an approaching tropical wave with more low-level vorticity should sort of 'sync-up' with it overnight/tomorrow and get the ball rolling. it's going to start out big and broad, so probably won't strengthen quickly or start trucking along very fast until mid-week or so, when it should have a decent degree of itcz separation and a steady easterly current to ride. models imply a threat to the northern leeward islands at the end of next week, and (gfs/ecmwf) eventual recurvature near the bahamas in around ten days. that far out it's hard to know if the models have future amplifications timed or the speed/profile of shortwaves right... not to mention our other area of concern.
that would be the frontal tail and cut-off area of mid-level energy, the frequent source of july activity, in the h50 break near the southeast coast. nhc is already honed in on the small vortmax/slightly sheared thunderstorm area due east of savannah by 150 miles or so. other models have different variations of this evolution... as the weakness troughs out and fills in, in spite of modest shear, the persistent disturbed weather may start to consolidate into yet another system somewhere between florida and the coastal carolina waters. this is in an area of vacillating/weak steering currents, and close enough to bertha to feel the tug maybe... so anything that does go will likely wander about also. this is still fairly low probability of a full development, though, per nhc. expect little movement and possible slow development (but fairly rapid development for anything that gets established).
this year is starting to have the look of a blockbuster to me. sure, it could easily reverse... but those persistent easterly upper anomalies over much of the tropical atlantic are going to start paying huge dividends in august, if they stay around.
HF 1341z13july
| LoisCane |
| (Veteran Storm Chaser) |
| Sun Jul 13 2008 02:39 PM |
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Re: trifecta
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How does the new wave off of Africa play into this set up and specifically with relation to 94L
http://oiswww.eumetsat.org/SDDI/cgi/listImages.pl?m=prod,sa=9,pr=RGB,c=AIR
Looks like a strong wave and has kept its signature through most of it's continental trek much like Bertha did though perhaps not as strong a signal.
http://www.ssd.noaa.gov/eumet/eatl/loop-bd.html
http://www.ssd.noaa.gov/eumet/eatl/rb-l.jpg
Great write up on the Trifecta and would imagine depending on what Bertha does and how soon she leaves could seriously affect any wave coming off Africa let alone at mid-ocean.
| scottsvb |
| (Weather Master) |
| Sun Jul 13 2008 02:39 PM |
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Re: trifecta
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I couldnt get enough info and sat fix-data missed a area around 11N and 51W that I been watching over the last 36hrs. I feel this has a decent chance to be slipping under the radar for a quick upgraded to Tropical Storm status in the next day or 2. The convection has been persistant over this area since 41W or 36 hrs ago, and I'm afraid we might have a tight circulation in there. Until Sat gets a fix (hopefully the next pass) we wont know forsure or until it gets better organized. I'm not sure there is alot of W-NW winds. Bouys nearby do show N-E-SW winds in a broader area.
Model runs try to pick up on this area first as it races it towards the Jamaica area by Weds-Thurs timeframe.
| Hugh |
| (Senior Storm Chaser) |
| Sun Jul 13 2008 04:01 PM |
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Re: trifecta
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94L definately looks large and impressive right now, but it's extremely far to the south to be a threat to the NORTHERN islands, isn't it? Maybe I'm missing something, but it looks like more of a threat to Trinidad and Tobago. The GFS run has now backed off saying that a major hurricane was going to be knocking on my back door in 13 days. Convection with 94L is rather disorganized too, so it'll be an interesting couple of days to watch it develop.
Bertha appears to be fizzling, convection-wise at least... still a solid spin to it, but it appears to be buckling under itself.
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danielw
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| (Moderator) |
| Sun Jul 13 2008 05:18 PM |
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Bertha Vortex Message
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Despite the visible presentation of Tropical Storm Bertha the Hurricane Hunters are finding that she still has some hurricane force wind speeds in the NW quadrant.
Storm BERTHA: Observed By Air Force #307
Storm #02 in Atlantic Ocean
Maximum Flight Level Winds Were 68KT (78.2mph 125.9km/h) In NW Quadrant At 16:17:30 Z
Estimated Max Surface Winds 61.2KT (70.4mph 113.3km/h) *
Date/Time of Recon Report: Sunday, July 13, 2008 11:36:00 AM (Sun, 13 Jul 2008 16:36:00 UTC)
Position of the center: 29° 53' N 062° 50' W (29.9°N 62.8°W) [See Map]
Minimum Height Measured At Standard Level Of 700mb: 2981m (Normal: 3011)
Surface Winds Were Estimated At: 47KT (54.05MPH 87.0km/h)
Estimated Surface Winds Were Measured 66nm (75.9miles) From Center At Bearing 309°
Maximum Flight Level Winds Near Center Were 68KT (78.2mph 125.9km/h) From 043°
Maximum Flight Level Winds Were Measured 66nm (75.9 miles) From Center At Bearing 309°
Minimum pressure: 991mb (29.26in)
Eye Wall Characterization Not Reported
Eye Did Not Have A Definable Form or was not reported
Center Fix Established Using: Penetration Radar Wind Pressure Temperature
Center Fix Established At Level(s): 700mb
Navigational Accuracy Measured At 0.02nm
Meteorological Accuracy Measured At 1nm
* = Estimated Surface Winds are assumed 90% of Max Flight Level Winds
| Hugh |
| (Senior Storm Chaser) |
| Sun Jul 13 2008 05:36 PM |
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Re: Bertha Vortex Message
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That's only at Flight Level, that they are finding hurricane-force winds, though, and if you use an 80% reduction, it only leaves winds of 62.5mph at the surface. Not sure how they determine whether to use 90% or 80% reduction from the flight level.
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danielw
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| (Moderator) |
| Sun Jul 13 2008 05:48 PM |
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Re: Bertha Vortex Message
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That is correct. Hurricane force winds at flight level.
I was slightly surprised at the wind speed due to the satellite presentation. However, Bertha is sandwiched between high pressure to the west and low pressure to the east. Which would seem to assist in accelerating the winds. Much in the same way that you can keep a ball spinning on the ground. One hand pulling and the other hand pushing.
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danielw
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| (Moderator) |
| Sun Jul 13 2008 05:52 PM |
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Re: Bertha Vortex Message
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Quote:
That's only at Flight Level, that they are finding hurricane-force winds, though, and if you use an 80% reduction, it only leaves winds of 62.5mph at the surface. Not sure how they determine whether to use 90% or 80% reduction from the flight level.
Currently, 2008, they use 90% for most of the 700mb or 10,000 foot level winds.
The other adjustments are for the 1000mb and 850mb flight levels which are mainly used on INVEST flights for Tropical Depressions and Tropical Storms with low wind speeds.
1000mb flight level is rarely used as it's usually too close to the water for Safety purposes.
| Rich B |
| (British Meteorologist) |
| Sun Jul 13 2008 06:01 PM |
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Re: Bertha Vortex Message
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Well Bertha has done it again, and according to the intermediate advisory, has stalled again! The slow motion has been her downfall, as upper-level conditions have been somewhat favourable. However, the combination of an ERC that never really finished, and the upwelling caused by her lack of motion, has led to her weakening. Satellite imagery shows a well defined sytem, with a vigorous circulation, but not much in the way of deep and strong convection. Still, should be a good rainmaker for Bermuda, which they need at the moment as the island is in the grip of a pretty severe water shortage!
| Hugh |
| (Senior Storm Chaser) |
| Sun Jul 13 2008 06:01 PM |
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Re: Bertha Vortex Message
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[quoteCurrently, 2008, they use 90% for most of the 700mb or 10,000 foot level winds.
The other adjustments are for the 1000mb and 850mb flight levels which are mainly used on INVEST flights for Tropical Depressions and Tropical Storms with low wind speeds.
1000mb flight level is rarely used as it's usually too close to the water for Safety purposes.
Cool. Of course, every storm is different and I've seen cases where measured winds were not close to the 90% range. In this case, I'm looking more at satellite presentation in thinking Bertha isn't close to its former self. In fact, it doesn't look like much more than a mid-latitude low/frontal zone. I just loaded the Bermuda radar, and it does still look like a tropical storm there.
| LoisCane |
| (Veteran Storm Chaser) |
| Sun Jul 13 2008 09:45 PM |
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Re: Bertha Vortex Message
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Don't be misled but her sat presentation. She's hung in there all afternoon and has found ways to get more moisture and build back some color.
Sats are great but nothing like having recon in there.
http://cimss.ssec.wisc.edu/tropic/real-time/tpw2/natl/main.html
Avila called it "vigorous" at the 5pm.
| weathernet |
| (Storm Tracker) |
| Sun Jul 13 2008 09:58 PM |
Cristobal - "The Wave"
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As Hank mentioned earlier today, this classified wave continues to slowly take shape. Looks like some consolidation may be starting to occur and given this systems overall size, would assume a primarily westward ( or WNW ) motion would ensue. Would not surprise me to see a slightly faster initial motion once the systems overall organization improves.
Aside from having spent my $500,000 winnings from Bertha / 1st named hurricane contest, I never would have anticipated such a record East Longitude area of formation. That, along with this years impressive tropical waves coming off Africa, I am even more curious as to the seeming lack of July Sahara dust, and the less than typical higher surface pressures in the tropics that is also common in July. Add these other curiosities, along with that which we have already seen this season, and this Atlantic season only continues to suggest a lot of interesting stuff to come. More importantly, Bertha had a recurvature track and will be curious to see if the next Eastern Atlantic tropical storm will follow suit or rather establish a more westward track. Normally when I see storm tracks which recurve, others forming in the same overall region tend to follow. Then again, the season is early and we may only now be seeing what the overall long wave pattern may be setting up to be. Given the overall typical ridging ( low and mid levels ) which is typical to July, I think the Greater Antilles need heed anything approaching from the east.
Having been away for a couple weeks, can anyone pass on what the most current SST's are for 94L, as well as the recent couple weeks trending for the central tropical Atlantic? I know the SST's off Africa were warm, but than cooled quickly.
| cieldumort |
| (Moderator) |
| Sun Jul 13 2008 10:18 PM |
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Re: Bertha Vortex Message
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I find that TCs losing their deep convection tend to have the winds "lift" well above the boundary layer, and as a rule, find that assigning a 60% to 80% reduction ratio from h70 (based mostly on a blend of taking the amount and intensity of convection into consideration, along with persistence, and the surrounding surface pressures) actually works quite well. A cyclone with as weak as convection as Bertha now has could easily be running as low as 70% at the surface, adjusted from 700mb, but 80% is probably as good as any right now, accounting for the nearby location of the shortwave ridge, and overall MSLP.
| Hugh |
| (Senior Storm Chaser) |
| Sun Jul 13 2008 11:36 PM |
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Re: Bertha Vortex Message
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94L is showing just a HINT of a circulation, I think, but not much of one.. but some very impressive convection. Not sure what's preventing the circulation from getting together.
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MikeC
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| (Admin) |
| Sun Jul 13 2008 11:40 PM |
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Re: Bertha Vortex Message
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It appears 94L may become the first "hype monster" of the season, most likely for its location and model projections. Right now it has no reason to be that.
I have to remind everyone it's still mid July, and this storm has to overcome less than perfect conditions to get organized. I think 94L is worth watching, but not really indicative of an active season yet.
I'll be more curious this time tomorrow to see how well the system has organized. It has a lot of convection, but you have to stretch to see any circulation. And that's why I'm not so sure on it doing much right now.
Tomorrow will be interesting to watch.
I added a new user mapping feature to the site, if you have a flhurricane login, check out this link.
| Hugh |
| (Senior Storm Chaser) |
| Sun Jul 13 2008 11:48 PM |
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Re: Bertha Vortex Message
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I think you've got a good point, Mike. Even if 94L were to become Cristobal in the next couple of days, it's got to cross the Graveyard (eastern Caribbean). It's interesting to watch, though.
| ftlaudbob |
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| Sun Jul 13 2008 11:59 PM |
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Re: Bertha Vortex Message
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If,and it's a big if,94l does develop into a cane,I for one would really start to think we will have a very busy season.Bertha set a number of records,let's not have any more records broken.
p.s, Like the new feature,
| cieldumort |
| (Moderator) |
| Mon Jul 14 2008 01:27 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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94L is looking extremely healthy tonight. NHC just increased their "48-hour formation potential" risk level to "HIGH" from "MEDIUM," and I see no reason at all why this is not appropriate. Much like 92L, 94L is not merely some early season open wave, but already a well-formed area of low pressure with thunderstorms co-located within its heart. 94L has also remained nestled within an area of significant TPW, and favorable wind shear.
The actual text of the NHC TWO now reads
Quote:
THE TROPICAL WAVE AND BROAD AREA OF LOW PRESSURE LOCATED ABOUT 1500
MILES EAST OF THE SOUTHERN WINDWARD ISLANDS IS SHOWING SIGNS OF
ORGANIZATION. THIS SYSTEM COULD DEVELOP INTO A TROPICAL DEPRESSION
AT ANY TIME DURING THE NEXT DAY OR SO AS IT MOVES GENERALLY
WESTWARD AT 10 TO 15 MPH.
Over the past several hours convection has gone from light, moderate and scattered to widespread and deep, and now appears to be blowing up over an incipient LLC.
| Hugh |
| (Senior Storm Chaser) |
| Mon Jul 14 2008 01:39 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
Over the past several hours convection has gone from light, moderate and scattered to widespread and deep, and now appears to be blowing up over an incipient LLC.
I was just about to note that, too. The hint of a circulation that I mentioned earlier, is still there... and it's looking very impressive right now, overall. Rapid movement could slow its development, but that didn't hamper Bertha's development at all. Generally when the NHC says something like "A tropical depression could form at any time", they're looking for something very specific that they haven't seen yet. If the current apparently organization continues overnight, I believe advisories may be initiated as early as 5am, when visible imagery should be available.
The long-term model tracks for this system are extremely disconcerting. GFS and GFDL imply an eastern seaboard threat, while LBAR and BAMM indicate a South American impact. BAMD, which is the most up-to-date model on WU, splits the difference, taking the system straight through the central Caribbean, on a path toward Jamaica.
| hurricaneguy |
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| Mon Jul 14 2008 02:02 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Looking good tonight, D-Max should be interesting.
(Inappropriate comments removed - wishcasting is not allowed on this site.)
| Freezey |
| (Verified CFHC User) |
| Mon Jul 14 2008 02:09 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Im not sure if the 2nd thing were watching is 94L or the L that was off the eastcoast but has anyone seen the spin starting in the next big wave right behind 94L? it wouldnt suprise me if we see a second invest after 94L develops.
| LoisCane |
| (Veteran Storm Chaser) |
| Mon Jul 14 2008 02:30 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Dvorak shows a strongly centered system totally different from the way it looked this morning.
Whether it's upgraded tonight or in the morning the trend is towards a rapidly deepening system pulling itself together.
http://www.ssd.noaa.gov/goes/flt/t2/loop-bd.html
http://www.ssd.noaa.gov/goes/flt/t2/loop-jsl.html
| Hugh |
| (Senior Storm Chaser) |
| Mon Jul 14 2008 02:51 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
Dvorak shows a strongly centered system totally different from the way it looked this morning.
Whether it's upgraded tonight or in the morning the trend is towards a rapidly deepening system pulling itself together.
Just as I suspected, unfortunately, from my own look at the Dvorak loop an hour or two ago. Based upon the way Bertha blew up extremely rapidly, I suspect we may see the same thing happen with what will be Cristobal, except that Cristobal will be on a path that will take it through the Lesser Antilles. Of course, it's too early to say for sure, but the possibility is there for a very strong system in very little time.
| craigm |
| (Storm Tracker) |
| Mon Jul 14 2008 03:01 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Rapid intensification seems to be the catch phrase this year. What was it last year? Season with no reason? Anyway, lack of shear is always a factor and I don't see much at all in front of 94L.
http://www.meteo.psu.edu/~gadomski/COMPSHEARATL_0z/comploop.html
| cieldumort |
| (Moderator) |
| Mon Jul 14 2008 03:04 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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A couple of other images (loops) which add even more evidence to the Dvorak-enhanced loop provided above that 94L is very nearly right on the cusp already tonight, and has quite a lot going for it.
10-hour Tropical ATL IR loop from NRL
Several days worth of TPW and h85 winds over the Tropical ATL (NRL loop).
As for T numbers, the Dvorak loop could be a little misleading. It should be very helpful to get a couple of clearer microwave passes overnight tonight, but guessing by the looks of things, 94L seems to be a little northwest of where NRL is pegging it right now... closer to the two balls of deepest convection which are a touch north of 10N, and if this is so, probably already up to a T number at or near 1.5
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MikeC
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| (Admin) |
| Mon Jul 14 2008 03:56 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Given the flare ups haven't really stuck, I'm not so sure yet. If it does take it may gain quickly, but I'm not sure it has yet. It still looks to me that part of it is still in the Intra Tropical Convergence Zone, if more of it escapes I think it has a shot. The surface data that's there--not much-- suggest a surface low of some sort is trying to form.
Probably mid-late tomorrow, or Tuesday if it does. Positive factors tonight include some surface data showing a low level circulation, and copious amounts of lightning, which tend to favor strengthening (even rapid). Most tropical storms do not have any lightning when they become organized (except in extreme rapid intensification)
That said, it's likely model runs will bend more westward, which means the Windward islands should be the most interested in this, followed by the leeward. Track beyond that is in the realm of speculation, even so it seems likely more due westward.
| cieldumort |
| (Moderator) |
| Mon Jul 14 2008 05:25 AM |
| Attachment |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Looking through what little bit of *cough* crystalball we have to work with tonight, it really strikes me that 94L is almost all but free of the ITCZ now. Perhaps a few feeder bands coming in from out of the monsoon trof, but that's about it. Water vapor imagery really starting to showcase the rapid improvement in organization that has taken place just over the last four or five hours, or so.
Uploaded an image that I've done some back of the hand doodles on of the ATL from around midnight eastern time.
| Freezey |
| (Verified CFHC User) |
| Mon Jul 14 2008 05:33 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Is it more is did 94L just seperated into another area of circulation ubder it?.....then theres the large wave off behind it.
| scottsvb |
| (Weather Master) |
| Mon Jul 14 2008 05:38 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Looking at my disturbance ... near 11N and 51W this morning(sunday) it has quickly raced off to the W with the LLF and is now around 11N and 58W as of late Sunday night. The convection died off as presures rose slightly with the overall disturbance racing away from the itzc. Still though a weak tight circulation is there, if convection builds around this area on Monday...we may have something by Tuesday or Weds appoaching Hispaniola and Jamaica later in the week. I give this a 3/10 but still something to watch.
94L looks well organized and cant say much more than anyone else has said on here or the NHC...so until its offical... Ill leave it alone as also the models are hit or miss on this.
Bertha? giving fish some fresh water!
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danielw
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| Mon Jul 14 2008 05:40 AM |
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Bertha, 94L and the Bahamas
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I've enlarged the satellite thumbnail in the upper right corner to permit viewing of the Bahamas also.
Moderate sized persistant area of thunderstorms over the Lower Bahamas at this time.
94L continues to consolidate it's convection. Two lobes of convection near the center. Probably will be named Tropical Depression by 11am EDT. Or 10 hours at the present rate of intensification.
Bertha... and the beat goes on. She still hasn't crossed the 31.0 North latitude line.
| weathernet |
| (Storm Tracker) |
| Mon Jul 14 2008 05:43 AM |
Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Mike~ I must disagree with your perception of 94L not having been seperated from the ITCZ. Though we do not have the luxury yet of visable pictures yet, it seems very evident to me that we have one large tropical cyclone with a dominant circulation. The overall circulation appears to me to be centered between 11-12N, and appears quite impressive on the JSL resolution.
With regard to those those concerned about anticipated "hype" relating to 94L, suffice it to say that when NHC claims a system may develop into a Tropical Depression at any time...., this often means "...we have a depression and lets get one more scat pass or some vis. sats to verify. I would also say that I do not see any inhibiting factors for what appears to be a fairly good size envelope/system to develop into a named storm within 24 hours. Beyond that, I am seeing differing and altering data on how strong this system might develop into, and also think too premature to speculate on that yet. With regards to potential motion and possible short term concerns......, it is not a stretch to say that some portion of the Lesser Antilies may well be threatened by some form of Tropical Storm ( or greater? ) conditions in the few days to come. 94L appears to be moving westward under a building mid level E. Atlantic ridge, and as most larger envelope systems go more westward, there does not seem to be any digging mid Atlantic troughs to break down the ridge in place. Only fly in the ointment could be T.S. Bertha, but it appears to be cut off from the westerlies and trapped in the very ridge, that should also keep 94L on a general 270-285 heading in the short term.
While the convection may wane in its intensity and not yet offer a consistant CDO, I would suggest that if a bursting process continues, this at minimum would seem to indicate slow falling surface pressures. I see no appearant upper level shear and outflow to the northwest to northeast quadrants do not appear inhibited at this time. I'll go out waaaaaaaaaaaaaaaaay out on a limb and guess 94L to be a named depression by 5:00pm Monday eve. ( though I would guess named Cristobal by sometime Monday night as well ).
(That indeed would be way out on a limb - we have only had a few model runs - most of them from the tropical suite - give it a chance to form first - initial model runs were initiated too far to the south.)
| Clark |
| (Meteorologist) |
| Mon Jul 14 2008 07:14 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Fun times for mid-July, huh? Well, obviously depends on your definition of fun, but so far for storm trackers, we've had some fish. That may change.
Bertha is eventually going to go out to sea, in good agreement with model guidance. SSTs aren't terribly warm as it moves north and east, but they are probably warmer than the upwelled waters we have now. Some daily SST products I've seen elsewhere show this remarkably well in both the actual SST fields and the day-to-day change in their anomalies. If it moves out a tad here soon, the SSTs and relatively low storm-relative shear should allow Bertha to at least maintain itself for awhile.
(As an aside, it will be interesting to see how the SSTs in that area S/E of Bermuda evolve over coming weeks. We're still in the time frame where they tend to increase through time, but Bertha has done quite a number there this week. Anything that ends up in that area for the next week or two will have a shallow/low amount of oceanic heat to work with.)
94L should become our 3rd depression sometime today, then our 3rd storm sometime in the next few days. Bertha is not likely to be big enough as a tropical system nor expansive enough as a transitioning system to provide more than a tug northward on this feature. How much of a tug it gives will likely be dependent upon how fast 94L develops and how slowly both it and Bertha move in coming days. It'll ultimately determine whether it ends up crossing parts of the Lesser & Greater Antilles or not. Given the strong influence the Greater Antilles can have on storm structure and intensity, it's really tough to have any confidence beyond five days in terms of a track forecast -- moreso than it would be in any other case. Long-range models haven't done well with the pattern across the US this summer, resulting in even less confidence. Summing it up: as always, long range speculation isn't exactly something to make time with right now and everyone across the islands into the Bahamas and the southeast needs to keep an eye on this one.
| cieldumort |
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| Mon Jul 14 2008 07:47 AM |
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Bertha lurches towards Bermuda
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Conditions are starting to rapidly deteriorate in and around Bermuda. As of 3:30 AM EDT, Tropical Storm Bertha has given up sitting and spinning for a decidedly good pace towards the northwest/north-northwest... and currently almost a bee-line towards Bermuda.
Having the benefit of moving over waters that haven't been upwelled, Bertha is now starting to travel back over SSTs that are running a hearty 27-28C, and at a rate of forward motion that just about guarantees no upwelling of any significance, especially given her weakened state. Some convection has started firing up within her center and outer rainbands, and what was at best the ghost of a ghost of an eyewall has begun reasserting itself a tiny little bit, with some hints at attempting to flare back up.
Bermuda is located at roughly 32.4° N 64.7° W. The center of Bertha is currently close to 31.2° N 63.7° W, and tracking along generally northwest or north-northwest t at something around 7 mph. A buoy located at 32.37° N 64.7°W, Station BEPB6 - 2695540 - Bermuda Esso Pier, is at this hour experiencing sustained winds of up to 30 knots, gusting to 37 knots. (Keep in mind that Bermuda is still located in the left-front quad, which is also still quite lacking in convection, in addition to just being the often weaker, left-front quadrant).
| Freezey |
| (Verified CFHC User) |
| Mon Jul 14 2008 09:03 AM |
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Re: Bertha lurches towards Bermuda
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On the Current View of Invest 94L it seems as its trying to form a Eye at an early stage...for some reason I see this one hitting rapid intensification in a big bloom of convection up to a Cat 1 when it hits the warmer waters head. though its just my 2 cents..... also can anyone give me some insight on the what seems to be circulation under 94L that it split from&the large wave off the African cost?
| cieldumort |
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| Mon Jul 14 2008 09:10 AM |
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Re: Bertha lurches towards Bermuda
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No eye forming within Invest 94L, although I think I see what you are referring to. This is just an optical illusion created by various cloud patterns. This sort of thing happens fairly often and should not be of any concern. We'll worry about eyes forming in what 94L may very well become, later.
Regarding water temperatures and development, SSTs are only one small part of a much larger mix of ingredients that go into baking and topping off tropical cyclones.
The convective complex south-southeast of 94L could be getting a very slight bit of spin to it in the lower levels, but really not much. Most of the apparent spin is actually likely yet another illusion, this one created by the direction of some of the mid/upper level winds crossing the lower-mid level winds within this part of the ITCZ, which it is a part of. Any spin it has near the surface would almost certainly be too close to the equator, at this juncture, to have much chance at development beyond being a monsoon depression within the ITCZ.
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MikeC
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| Mon Jul 14 2008 10:35 AM |
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Re: Bertha lurches towards Bermuda
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Judging from the quickscat passes from overnight, 94L really isn't too organized yet, in fact still not all that impressive at all.
Perhaps by late today or tomorrow it could become more organized. Something to watch, for sure but it's by no means a sure bet.
Bertha is very close to Bermuda now as a fairly strong Tropical Storm, though.
I'll update later today.
| Wingman51 |
| (Weather Guru) |
| Mon Jul 14 2008 12:45 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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With 94L trending so much further south than Bertha, when should we look for the poleward movement? I know the SST's are more conducive for development on 94's current path but what is the shear forcast for the near future. One last question and I'll go back to lurking - - For the past few years we have heard a lot about Saharan Dust but not so much this year. Is there a correllation between the absence of dust and the early wave train in the CV region? Thanks
| LoisCane |
| (Veteran Storm Chaser) |
| Mon Jul 14 2008 01:39 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Think it's more a lack of shear.
A lot of things all coming together to help kick off the CV season early.
Quality of waves coming of Africa for one.
Position of the waves.. usually this time of year (and in June) they are still low, low and get caught in the ITCZ or they crash into Africa.
Spacing of waves, just far enough apart for each to try and develop.
Movement west, forward speed has been slow and steady. Often they shoot off too fast and out run their circulation. Note..a little worried on this way having that problem but this wave seems more like a hybrid wave.
Warm water relatively. Even a few degrees makes a big difference in that region with a good wave rolling off that already has a low pressure system attached and comes off spinning as we say.
Dust... funny thing with dust. Too much can kill it if there is another mitigating factor but sometimes I think a little dust is good. And, the dust storms this year seems to break up easily as the waves crash into them. Some people hold small particles of dust can actually help pull a storm together. The jury is out.
NOTE: This new wave has brought out all the biggies on the board and just for that reason alone it compels us to watch this wave as it is entering a region where it will affect someone .. islands earlier, US Coast possibly later.
Season begins if you ask me.
Bertha might have been a rarity but the Atlantic Season is open and not just for fishing.
| Unregistered User |
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| Mon Jul 14 2008 02:04 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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I looked at the satellite this morning and noticed some circulation off the florida coast....I am unsure if this is remnants of the passing front or if this indeed something to watch. SST are ripe for something to develop, if this is something to watch out for. I know that sometimes things do develop off the coast of Fl. I remember in 2005 such said thing happend and passed right over us in Mayport. Dumped alot of rain.
Anyone else care to fill me in as to what I may be seeing off the coat of Fl?
| metwannabe |
| (Weather Hobbyist) |
| Mon Jul 14 2008 02:20 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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First vis sat loops of 94L appears, to these amateur eyes anyway, to have decent circulation. I know the thunder storm activity has decreased but certainly appears to have a closed circulation. Isn't that enough to be termed a depression? :?:
| cieldumort |
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| Mon Jul 14 2008 02:51 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
I looked at the satellite this morning and noticed some circulation off the florida coast....I am unsure if this is remnants of the passing front or if this indeed something to watch. SST are ripe for something to develop, if this is something to watch out for.
An upper-level low is centered off the east coasts of Florida and Georgia. This feature is in the upper-levels, with next to nothing at all down near the surface, less an associated trof cutting across the middle of the state from SW to NE. Really nothing at all to work off of at the moment, but Florida can probably expect to see some more storminess today from coast to coast.
While SSTs in that region are supportive of genesis, one can almost toss out looking at SSTs as any indication of whether or not an area, itself, is "ripe" for development. Warm core cyclone formation is dictated much more by what is happening above the water, than below.
| cieldumort |
| (Moderator) |
| Mon Jul 14 2008 02:58 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
First vis sat loops of 94L appears, to these amateur eyes anyway, to have decent circulation. I know the thunder storm activity has decreased but certainly appears to have a closed circulation. Isn't that enough to be termed a depression? :?:
At this time, 94L's surface circulation, while obvious, is also uneven, and oblong. Furthermore, 94 has been seriously lacking deep convection since last night's burst gave up the ghost. For these reasons, 94L does not qualify as a tropical depression, but its prospects are still good for further development over the course of the next few days
| doug |
| (Weather Analyst) |
| Mon Jul 14 2008 03:06 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Re: 94L, You are correct, the prospects appear good. In fact it seems the system is beginning the transition now. I see a feeder system to the south, tapping into the ITCZ, and one to the SW where some cooler tops are beginning to form. There is also moisture streaming in from the NE. The band of TStorms on the north of the apparent COC is prominent. Not the prettiest picture, but I have seen worse classified. I think this is of high probability for eventual classification (with 24 hrs.)
| Cat 5orBust |
| (Weather Hobbyist) |
| Mon Jul 14 2008 03:11 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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With Bertha still lurking and soon to be on the move out, with 94L, and with other large thunderstorm complexes over Africa, this is certainly looking to be a lengthy Cape Verde season. This does not suggest that it will be an overly above active season although things are getting off to a quick start. As far as 94L, the models keep suggesting that this will possibly impact the islands, the Caribbean islands, and who knows what after. It is still way too early to know if these areas will be affected, but the indications are that if this feature does re-curve, it will get a lot further west than Bertha got and it is also further south which would put land areas at a potentially higher risk. Just looking at some views of 94L it seems to have some good circulation, but is lacking storms near a broad center of circulation? Plenty of time to watch as we know models change all the time. Everyone should have supplies already and with all of the media outlets and websites to be able to track things, no one should be caught off guard.
| cieldumort |
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| Mon Jul 14 2008 04:18 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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No argument in the expectation of 94L most likely becoming a TD within 48 hours, and perhaps as early as later today.
Near term (over the next 48 hours) there are some obstacles which could hold 94L back from becoming more than a low-end TS.. in the near term.. (over the next 48 hours)... and probably will most have to do with the dry air which exists just to the W-NW-N of the system, dry air that has already been a little entrained into the broader circulation when the overnight convective burst went out.
What exists now is a banding ring of convection around the northern and southern halves. Within this ring, dry air is squelching any significant convection from growing back over the feeble LLC. Eventually, as the embryonic cyclone continues to produce yet more convection, this dry air should slowly mix out, but this might not happen soon enough, as the eastern Caribbean awaits, which could prove to be a harsh blend of unfortunate timing. Time will tell. Odds favor 94L beating this and coming out the winner, however.
On some of the upsides, 94L has an apparent anticyclone aloft, with outflow fairly well established all around. Shear remains low, and SSTs continue to go up along its future path over the next several days.
| scottsvb |
| (Weather Master) |
| Mon Jul 14 2008 04:29 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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This system (94L) needs concentrated T-Storms near the COC for this or any system to be classified... I dont see this happening until at least Tuesday if this does develop at all. I think in a weird way...this is more of a Midlevel circulation...and even though there is a LLC...its lacking the Mositure in the LLevels..(its pretty dry).
My little feature I been watching is now near 11.5N and 63W racing W behind a trough out near 66W...small and compact but lacking SW winds due to its 25mph forward speed with a strong high N of Puerto Rico. When this gets S of Jamaica later Tuesday night..it should slow some and give this more of a posibility...still 3/10 chance.
| typhoon_tip |
| (Meteorologist) |
| Mon Jul 14 2008 04:53 PM |
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Re: Bertha Near Bermuda, Watching Wave East of the Lesser Antilles
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It is interesting to me that the GFS model went from multi-day, multi-run consistency for development of 94L...for a weeks worth of runs for that matter...and then all at once last night's 00z run abandoned the idea almost entirely, leaving only an open wave to pass harmlessly into the Caribbean.
That strikes me suspiciously as some kind of data ingest and/or assimilation errors being fed into the model. The 06z run continued that no development idea.
The GFDL went south and weaker, but that is understandable because the GFDL is initialized/parameterized off the GFS data; perhaps another clue the that GFS has been dealt some odd data for processing.
It should be noted, however, that the ECM has not really been too happy about this system, for about the last 3 day's worth of runs. It did have it 4 and 5 days back, more robustly, but since has been paltry at best.
Currently, there is a fairly obvious cyclonic curl to the convective debris/showers of 94L. I don't see any overwhelmingly negative factors for development. The deep layer shear analysis has a general easterly component at all levels; and given that 94L is in fact moving west means that here storm relative shear is actually quite low. That said, with amply warm water and decent capacity for instantiating anticyclonic outflow above any convective concentrations that get going near the core, this should have an opportunity to develop. Interestingly, the last 1 hour of loop shows a rather obvious banded feature on the northern semi-circle, with cooling cloud tops.
It is important to note that even though the models did exceptionally well sniffing out Bertha prior to her birth, that does not necessarily mean they will all handle every situation with the same result. Sometimes the models will be vague about development and we wind up with a major hurricane, such as Felix (2007).
An ending idea to this... If a deeper system gets going, it may in fact end up more around the NE Windwards as opposed to cutting straight west in the Caribbean.
John
| xxflcyclonexx |
| (Verified CFHC User) |
| Mon Jul 14 2008 05:57 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Here's a doppler radar loop out of Bermuda http://www.weather.bm/radar.asp
Very well defined and healthy looking system. Most of the precip. appears to be on the left side.
| ftlaudbob |
| (Storm Chaser) |
| Mon Jul 14 2008 06:10 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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No question now,94L is really starting to spin.You can really see it on the last 2-3 frames.Outflow is looking good,low shear,high sst's,yea I think we got a live one.This is just way to early for these eastern storms.Maybe I should move to Ohio for the next few months .
| lawgator |
| (Weather Hobbyist) |
| Mon Jul 14 2008 06:51 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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The 2 pm EST models for 94L (with the exception of the rather odd-looking GFS) are fairly consistent in taking whatever 94 L decides to become just to the south of Hispaniola in a few days, taking a largely west of WNW track. I am recollecting a couple of storms from last year that just drove head-long into the Yucatan. If those models are correct on 94L, I suppose we might see a repeat of that. Anyone know if there is anything to nudge it north towards the end of the week, onto a track into the Gulf?
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MikeC
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| (Admin) |
| Mon Jul 14 2008 06:52 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Satellite estimates for 94L are at (SSD / t#s) are 2.0 now, which is probably enough to start considering it a candidate for a depression, possibly later tonight if it holds like this for a few hours.
| metwannabe |
| (Weather Hobbyist) |
| Mon Jul 14 2008 06:54 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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I agree. It looks very organized on vis sat. If thunder storm activity can increase (key word, if) then it appears to have potential to really take off. Definately worth watching!!
| CDMOrlando |
| (Weather Hobbyist) |
| Mon Jul 14 2008 07:23 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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[quote) ...I am recollecting a couple of storms from last year that just drove head-long into the Yucatan. If those models are correct on 94L, I suppose we might see a repeat of that. Anyone know if there is anything to nudge it north towards the end of the week, onto a track into the Gulf?
One year is different from another and you can not depend on storms taking the same track.
The steering current determine where a storm will go.
For Example, below are steering current that applied to Bertha
If you look here you will see the weak steering current from yesterday for Bertha.
CMISS
By today those currents changed to same site
As the large high over texas moves west the current flow/steering can and may well allow for a turn to the north. Depending on how strong 94l is at the time it reaches the area differnet level of steering currents could be in place.
Any speculation at this time is just that....
| typhoon_tip |
| (Meteorologist) |
| Mon Jul 14 2008 07:52 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
The 2 pm EST models for 94L (with the exception of the rather odd-looking GFS) are fairly consistent in taking whatever 94 L decides to become just to the south of Hispaniola in a few days, taking a largely west of WNW track. I am recollecting a couple of storms from last year that just drove head-long into the Yucatan. If those models are correct on 94L, I suppose we might see a repeat of that. Anyone know if there is anything to nudge it north towards the end of the week, onto a track into the Gulf?
It's more likely that the models are minoring out 94L, such that she's more susceptible to the lower tropospheric steering field. If she were a deeper integrated storm, she would probably model her way up N of Hisp.
| doug |
| (Weather Analyst) |
| Mon Jul 14 2008 08:57 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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At the risk of repeating my 11:06 post, in further review of the visible of 94L at 4:50 p.m. all the factors I noted 6 hours ago still are at work It looks much healthier now. The TStorms to the north have now been wrapped in to the west. A new Tstorm is flaring right on the west boundary of the LLC. new activity can also be seen to develop to the north More importantly all feeder mechanisms are improving. 94L seems to be on its way to further classification.
| xxflcyclonexx |
| (Verified CFHC User) |
| Mon Jul 14 2008 09:12 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Bertha is hitting Bermuda and 94l is growing and on the march..things are really hopping now.
These Bertha videos were just put out. The winds look very close to hurricane strength to me, and Bermuda is on the "weak" side of the storm.
Hurricane Bertha 14 July 08 2:25pm EST
http://youtube.com/watch?v=yHjf3HrBikw
July 14th 08 5.30pm St George Bermuda
Bertha blowing through
http://youtube.com/watch?v=Gjbv0QmX4qM
| MichaelA |
| (Weather Analyst) |
| Mon Jul 14 2008 10:23 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
94L seems to be on its way to further classification.
I agree since 94L's circulation appears to be separated from the ITCZ in the last vis sat pic. As for the Eastern Caribbean, the SW shear the was persistent in June into July is pretty much gone now. Even the wave in that area now is showing more activity than it did traversing the Atlantic.
| Hugh |
| (Senior Storm Chaser) |
| Mon Jul 14 2008 10:55 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Well, I was extremely bullish on 94L 24 hours ago. Indeed, I thought 24 hours ago, that by now, we'd be dealing with a 50+kt Cristobal.
Boy, when I'm wrong, I'm wrong!
T-numbers remain 2.0, but there is basically no convection with the circulation at this time... and it's heading toward an area of dry air, from looking at the water vapor loop.
| typhoon_tip |
| (Meteorologist) |
| Mon Jul 14 2008 11:10 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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I feel fairly confident that if 94L crosses the threshold of invest into organization, most guidance will be retarded with both rate of intensification, as well as ultimate intensity - but may catch up on the latter, later on - looking forward from that point in time.
Now-casting is probably the more important procedure with this particular entity. All environmental variables are positive for development and we do in fact have a wave with a closed low on its axis, exhibiting cyclonic curl in the convective plumes...amid said environment factors. Potential outflow is good, shear remains low, SST are warm, and there doesn't really appear to be much dry air in the vicinity, either. Because the models do or do not show this system is probably of lesser importances when noticing what is actually taking place. It is simply and most likely a matter of getting a nice sustained convection concentrate, which is probably a matter of time.
John
(Referenced 'quote' was from a post that was moved to a different Forum.)
| Hugh |
| (Senior Storm Chaser) |
| Mon Jul 14 2008 11:20 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
It is simply and most likely a matter of getting a nice sustained convection concentrate, which is probably a matter of time.
What's causing the delay, do you think, John?
I mean, Bertha formed extremely quickly, and in an environment that I didn't think was that much better than 94L.. yet 94L is making very little progress thusfar, despite favorable conditions.
(Please use the PM capability when addressing a particular site user.)
| typhoon_tip |
| (Meteorologist) |
| Mon Jul 14 2008 11:41 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:Quote:
It is simply and most likely a matter of getting a nice sustained convection concentrate, which is probably a matter of time.
What's causing the delay, do you think, John?
I mean, Bertha formed extremely quickly, and in an environment that I didn't think was that much better than 94L.. yet 94L is making very little progress thusfar, despite favorable conditions.
I think this particular storm is on schedule for what models were depicting, actually, a few days ago. The mystery in the models is why they are lost at the moment when clearly there is at least some steady improvement, albeit slow upon the hour. I wouldn't worry about that though, if you are an enthusiast for seeing these things on the map.
You have to remember that Bertha had a closed low robustly spinning upon leaving the African continent. Bertha was also pretty much a fantastic anomaly, actually, this one is too for that matter. One's an accident, but two? A bit intriguing and there's a physical/causal relationship to some back ground signal that really wants to get a CV season underway at least excuse imaginable. If we get a 3rd (which the 12z CMC suggests) that's a slam dunk and this season has something unique about it.
That said, 94L was a weak wave really when it came off Africa... In fact, we should really be more amazed that it has stoked that much momentum from so little.
John
| metwannabe |
| (Weather Hobbyist) |
| Mon Jul 14 2008 11:41 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Bertha may still have some surprises up her sleave. With that huge bowling bowl of an upper level low sitting NE of her I don't think she will make much more progress northward. In fact, the WV image appears to be showing signs of her being pulled eastward already. Also I noticed some of the model outputs are diverging again are any that show a southwestard movement reliable?
| Hugh |
| (Senior Storm Chaser) |
| Mon Jul 14 2008 11:54 PM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
I think this particular storm is on schedule for what models were depicting, actually, a few days ago. The mystery in the models is why they are lost at the moment when clearly there is at least some steady improvement, albeit slow upon the hour. I wouldn't worry about that though, if you are an enthusiast for seeing these things on the map.
You have to remember that Bertha had a closed low robustly spinning upon leaving the African continent. Bertha was also pretty much a fantastic anomaly, actually, this one is too for that matter. One's an accident, but two? A bit intriguing and there's a physical/causal relationship to some back ground signal that really wants to get a CV season underway at least excuse imaginable. If we get a 3rd (which the 12z CMC suggests) that's a slam dunk and this season has something unique about it.
That said, 94L was a weak wave really when it came off Africa... In fact, we should really be more amazed that it has stoked that much momentum from so little.
But.... 94L looked - to me - a lot more impressive 24 hours ago... and the GFS was going crazy with it at that time. Now, it looks pretty sick, and the GFS and GFDL actually lost it for two runs (they apear to have picked it back up now in the latest runs, though). Certainly 94L was weaker than Bertha when it came off Africa, but I don't see that it's done as the models projected, in terms of development. Were the models not forecasting it to have developed into a T.D. by now?
| Freezey |
| (Verified CFHC User) |
| Tue Jul 15 2008 12:03 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Hopefully it will make it out of its current area before the wave behind it cacthes up&messe up its chances of Development.However they could help each others development if at a safe distance from each other as they moistend up the air&filters out the Dry air
(im not hoping for anything bad to happen concering a potential harmful storm to hurt anyone,just find it wrather interesting to watch them develop)
| LoisCane |
| (Veteran Storm Chaser) |
| Tue Jul 15 2008 12:07 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Problem with models is that the timing is integrally related to intensity forecasting. If you are off on one you are off on the other. Track often can be seen but be off by a few day as often the path is set but the timing and intensity must jive or its garbage in and garbage out.
It has a large pocket, it spins nice on visible however it is not stacked properly and has a push me pull me motion to it's spin and I think it got separated from it's bottom half though not real sure if the convection running in tandem to it's south was part of it or another wave.
| typhoon_tip |
| (Meteorologist) |
| Tue Jul 15 2008 12:13 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
But.... 94L looked - to me - a lot more impressive 24 hours ago... and the GFS was going crazy with it at that time. Now, it looks pretty sick, and the GFS and GFDL actually lost it for two runs (they apear to have picked it back up now in the latest runs, though). Certainly 94L was weaker than Bertha when it came off Africa, but I don't see that it's done as the models projected, in terms of development. Were the models not forecasting it to have developed into a T.D. by now?
You know, the cyclonic curl today is more evident than it was yesterday during the convection flaring. Yesterday the low along the TW axis was being assessed at 1009mb....today 1008mb...so despite its lack of pretty red hues on IR...it's a stronger system; granted at a very slow pace. Let's see how the nocturnal typology unfolds. Wouldn't shock me to see some additional stuff flaring later...
| Hugh |
| (Senior Storm Chaser) |
| Tue Jul 15 2008 12:22 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
You know, the cyclonic curl today is more evident than it was yesterday during the convection flaring. Yesterday the low along the TW axis was being assessed at 1009mb....today 1008mb...so despite its lack of pretty red hues on IR...it's a stronger system; granted at a very slow pace. Let's see how the nocturnal typology unfolds. Wouldn't shock me to see some additional stuff flaring later...
That's definately true. Yesterday, the big question in my mind was if there was a circulation (at any level)... I figured, give it until morning when the visible loop will show if there is a circulation. So, this morning, the visible loop did indeed show a pretty decently defined LLC, but the convection was all but gone. Now, there is a VERY small hint of moisture right near the LLC (on water vapor) but nowhere else. When does the nocturnal maxima happen for where the system is now?
Newest TWO admits that convection has "decreased a little this evening. However...environmental conditions appear favorable for development...and this system still has the potential to become at tropical depression later tonight or Tuesday as it moves west-northwestward at 15 mph."
I'd say Tuesday is 100% more likely than later tonight.
| typhoon_tip |
| (Meteorologist) |
| Tue Jul 15 2008 03:39 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Quote:
I'd say Tuesday is 100% more likely than later tonight.
I'd say that is true whether or not big convection exploded overnight, unless something truly extraordinary happened. Which is not to say there's a 100% chance of TD status on Tuesday, just that there are better odds.
John
| weathernet |
| (Storm Tracker) |
| Tue Jul 15 2008 03:40 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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John - I concur with your analysis of 94L, with regard to overall conditions at hand. I too was incorrect in assuming a T.D. at this time -24 hours ago. That said, and upon a closer look at several different Sat. enhancements, it almost seems to me that some Altocumulus ( or some mid level certainly lower than 250mb level ) on the systems western periphery seems to be moving out and away, rather than inward more indicative of a better stacked cyclone. My take is that perhaps there was or now is, a less than vertical system in place. Again however, as you pointed out....conditions would seem favorable and given a new round of bursting convection, perhaps a new focused point of surface convergence and dropping pressures would quickly establish a fairly robust and "visible" cyclone, at least to the models.
One footnote- There would appear to be a slight rise to the SST's just ahead of 94 L, at approx. 52W. I honestly do expect to see some convective comeback overnight, but certainly as the system moves over this somewhat warmer water. As to the convective area over the ITC, just south and southeast of 94L, this too may have near term impacted inflow slightly. If we start seeing this convection suddenly acting as a "tap root" into 94L, rather than seperate from it, than we could be looking at one big wet one knocking at the Lesser Antilles door. Finally, though I do not see any outflow cloud fragments on the cyclone's northern quadrant being impacted by any obvious shear, the system is now passing directly south of the southernmost point of a mid to upper mid-Atlantic trough. I cannot help but wonder if this feature has had some short term retarding of development.
I am still "bullish" on this system for future development.
| scottsvb |
| (Weather Master) |
| Tue Jul 15 2008 03:49 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Well I do agree that moving over warmer ssts will help...but they are "OK" right now around 27-28C. Thing with 94L is...the LLC was only partially at the surface...infact its still there..but its mostly a midlevel system. The LLC is becoming elongated E-W during the last 12-24hrs.. only thing I can think of is..dry air in the upper levels caping cloud tops near 30,000ft. The MLC is well defined...while the LLC is weak and elongated now. I really dont see more than a midlevel center moving into the eastern carribean by Thursday and haven't been thrilled about this system.
System (wave) I been watching over the eastern carribean is still there...weaker than 94L but should continue towards the W carribean south of Jamaica by later Tueday into Weds...still giving this a 3/10 chance....upper level winds in the NW carribean are too hostile to develop this..but is better south of 15N (which it will probably stay).
| LoisCane |
| (Veteran Storm Chaser) |
| Tue Jul 15 2008 04:57 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Funny you mentioned that system in the Carib as I noticed tonight a few times and wondered why it hadn't been mentioned.
As much as I see it is possible for the invest to get its act together my eyes still go east towards the other wave:
http://cimss.ssec.wisc.edu/tropic/real-time/wavetrak/winds/m8wvupper.html
Which stands out bright yet no one talks about it yet.
Imagine we need a bit of patience, got the water hot enough now we have to wait and watch and something will pop. SAL shouldn't be a problem either as I was looking at that site.
Perhaps everything needs to settle for a day after Bertha departs, that's sure a lot of energy she displaced for a long time.
| scottsvb |
| (Weather Master) |
| Tue Jul 15 2008 06:41 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Indeed.....the center that everyones been watching has been a midlevel low with a weaker LLC...but due to this being a weaker system and a strong LL Ridge to its N....the LLC has raced out ahead of the MLC and is now near 13.1N and 47W or just east of the flare up of convection. Although there is drier air closer to the midelevel low...the LLC has moved into a better midlevel enviroment thus letting T-Storms to form on the western side of the LLC. Still though, I would want to see persistance into Tuesday.
Again the center most are seeing is just the MLC and the LLC is further west racing off to the W on the eastern side of the current flare up.
| cieldumort |
| (Moderator) |
| Tue Jul 15 2008 07:58 AM |
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Re: Bertha Stalls SSE of Bermuda, Watching Two Other Things
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Really have to disagree with that assesment.
Different take -
LLC much closer to, well, basically right at, 12N 45W, and finally starting to redevelop some (a little) convection right within it.
That hint of a spin off to the west-northwest (closer to 13N 47W) strikes me as resulting from the wrap-around convective balls we have been watching all day coming into contact with a conflicting layer or some sort.. so the tiny little complex probably hit a portion of the low-level/surface shear zone 94L has been roughly tending to follow, at the same it was rounding the smooth western edges of the oblong, broad circulation.
My best guess as to 94Ls LLC current position is about the same as the center location being tracked by NRL, currently listed at 11.9N-45.3W, on their website.
However, it will be curious if the flare near 13N 47W doesn't disrupt things a bit, as it might very well be in the process of developing a meso, and without a doubt, it's the best looking convective cluster of the bunch so far today or tonight.
* Going to edit and amend all that to say that I might be nudged to split the difference with scott. We need a few more microwave passes... -and- a scatt... to put this one together, but a recent AMSRE pass sort of hints that there may be a primary or secondary LLC running along or near 12N and west of 46W.
How do you spell dis-or-g-a-ni-zed?
(I know, it's not *that* disorganized, but it could certainly be said to have room for improvement)
As an aside, this is one of the longest stretches of Dvorak T numbers running 2.0 out of SAB, Tropical T numbers, in any case, without an upgrade:
15/0545 UTC 11.8N 45.1W T2.0/2.0 94L
14/2345 UTC 11.9N 44.2W T2.0/2.0 94L
14/1745 UTC 12.1N 43.1W T2.0/2.0 94L
14/1145 UTC 11.9N 42.0W T1.5/1.5 94L