MikeC
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| (Admin) |
| Thu Oct 03 2013 12:36 PM |
A Messy Karen in Central Gulf
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7 AM EDT 4 October 2013 Update
Tropical Storm Karen is a bit of a mess this morning, with a fairly large model split it's a bit reminiscent of tropical storm Debby from last year which was being "split" by the models, and eventually, opposite to the official forecast, began moving to the northeast.
This is a similar situation, but for different reasons. Karen is battling transitioning conditions, while the low level center remains exposed well to the west of most of the convection. The GFS model, showing a hard right curve, vs some of the other models taking it into Louisiana.
This makes it rather complex of a forecast, it may remain weak today, but has a window to restrengthen tomorrow. If the GFS winds up right, or even partially right, it will remain over water longer and shoot further east when a trough may actually bring favorable conditions. There still is a hurricane watch up for parts of the coast for this reason, and anyone in the cone needs to keep this in mind.
The forecast lounge will have a bit more on this. Odds favor it staying below hurricane strength, but only barely, and those in the area need to be prepared, particularly on the eastern side of the cone. Either way plenty of rainfall parts for east of the landfall location.
The good short term news, is that the shear is overtaking the system and weakening it and the low level circulation is exposed which favors the system staying weak. And odds are it will remain weak and a rainmaker. The wildcard is if any center reformations happen to the east or not.
Recon missions are running continually into the storm.
Original Update
Based on recon aircraft reports, the area of low pressure we have been tracking (97L) has entered into the southern Gulf with 60MPH maximum sustained winds and a closed circulation, thus Tropical Storm Karen. The cyclone is expected to be in a favorable environment for at least another day, and so will likely continue to strengthen the further north it gets.
Karen is forecast to become a hurricane. It will probably weaken some before approaching land, but how much depends on what its state is at the approach, and if it aligns with the shear, or not (which would be more likely if it tracks more to the right). Most likely it will be at tropical storm strength at landfall, probably on Saturday.
In short, the more west (left) in the cone Karen stays, the weaker it is likely to be; the further east (right) she travels, the more favorable for development. All of this depends on what impact the trough has on the system (which is likely the only thing that could nudge it much further east) Any in the hurricane watch area should be thinking about doing hurricane preps, though.
Hurricane watches are up from Grand Isle, Louisiana eastward to Indian Pass, FL (Southeast of Panama City)
The tropical storm watch was issues west of Grand Isle, LA to Morgan City, and includes New Orleans and Lake Pontchartrain.
Mark Sudduth & Mike Watkins from hurricanetrack.com are headed there now. Track them on a map here.
Radar Recording of 97L approach to Cancun ( Alternate Animator )
{{NortheastGulfRadar}}
{{StormLinks|98L|98|13|2013|98|98L}}
{{StormLinks|Karen|12|12|2013|12|Karen}}
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MikeC
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| (Admin) |
| Thu Oct 03 2013 01:50 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Recon is finding the center move a bit west, which is counter to where all the convection is, Karen is still a 50/50 split between getting itself together and falling apart. Moving more west would imply the weaker system .
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MikeC
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| (Admin) |
| Thu Oct 03 2013 03:53 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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The center of circulation appears exposed on the west side of the convection, so after strengthening a bit this morning it may wane a bit. If this thing reforms to the east or southeast it has a better chance, but it'll probably be officially stuck at current windspeed until recon gets back out again.
| Fairhopian |
| (Weather Watcher) |
| Thu Oct 03 2013 03:57 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Yes, I can definitely make out the lower level vorticity (RGB Sat) to the west of the main convection, which convection appears to be waning at the moment. However, at the same time, the overall outflow is definitely improving. An amateur question, but . . . Could the emerging outflow make it more likely that convection will re-fire closer to the center and/or contribute to some stacking near the prospective eye? (assuming sheer remains constant)
| typhoon_tip |
| (Meteorologist) |
| Thu Oct 03 2013 04:43 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Quote:
Yes, I can definitely make out the lower level vorticity (RGB Sat) to the west of the main convection, which convection appears to be waning at the moment. However, at the same time, the overall outflow is definitely improving. An amateur question, but . . . Could the emerging outflow make it more likely that convection will re-fire closer to the center and/or contribute to some stacking near the prospective eye? (assuming sheer remains constant)
We have to be careful with our assumptions on the outflow.
TPC overlays: Low, Mid, and High levels, but there are many intervening layers that can impose shear. The fact that the center has moved out W and convection and new/on-going convection did not collocate, "might" be an indication for an intervening layer of shear already impacting the vertical depths of the cyclone.
I am not totally certain of that either, but I have noticed a few times in the past where the overlays did not present shear, but TPC points out shear during their updates. I would not be surprised if they mention some rip off taking place in their next discussion.
Edit: Actually upon discretely analyzing the hi resolution visible imagery, I can see towers on the NE side of the low-level circulation, moving SE. That would be consistent with an unfavorable mid level vector impacting from the NW.
| Fairhopian |
| (Weather Watcher) |
| Thu Oct 03 2013 06:13 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Quote:
Actually upon discretely analyzing the hi resolution visible imagery, I can see towers on the NE side of the low-level circulation, moving SE. That would be consistent with an unfavorable mid level vector impacting from the NW.
I can see what you're describing quite well on the NRL, but for the past hour or so of SAT frames, those towers on the NE side now appear to also be building or wrapping cyclonically (ever so tightly) around the low-level circulation. Maybe growing in both directions and countering that mid level vector from the NW? Do you concur?
| typhoon_tip |
| (Meteorologist) |
| Thu Oct 03 2013 06:46 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Quote:Quote:
Actually upon discretely analyzing the hi resolution visible imagery, I can see towers on the NE side of the low-level circulation, moving SE. That would be consistent with an unfavorable mid level vector impacting from the NW.
I can see what you're describing quite well on the NRL, but for the past hour or so of SAT frames, those towers on the NE side now appear to also be building or wrapping cyclonically (ever so tightly) around the low-level circulation. Maybe growing in both directions and countering that mid level vector from the NW? Do you concur?
The "possible shear layer from the NW" idea was speculative based on sat obs -- let's keep that in mind. The next descriptive update from TPC will be telling, because they have the advantage of Recon and other observation techniques, of course.
As to the countering idea ... systems in the formulative phases of development do not typically possess the power to alter their environment in that way. So I would be less inclined to concur with that idea. Stronger systems may be more resistant to weaker shear penetration into there cores; if there is shear in some intervening layer, it is not likely Karen has yet acquired the ability to prevent it from incurring.
I am also noticing that there is a lot of dry air situated over the western and northern Gulf. It is also possible that a lot of this disrupted convection is because mid level dry air had been ingested. Evidence to support that is a strong arcus cloud feature propagating to the N and NW away from the center this hour. Dry air mixing into the convection promotes cold down burst due to evaporation, and these outflow boundaries can be symptomatic of that taking place.
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MikeC
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| (Admin) |
| Thu Oct 03 2013 07:34 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Recon seems to be finding slightly lower pressures, and windspeeds around 65mph, so no big changes (so far).
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MikeC
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| (Admin) |
| Thu Oct 03 2013 08:25 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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NOAA recon found 997mb, and some pretty high flight level winds, they may bump it up to 70mph at the 5PM Advisory, but those winds may not be hitting the surface, and they'll hold at 65mph (with the lower pressure).
| typhoon_tip |
| (Meteorologist) |
| Thu Oct 03 2013 08:52 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Interesting. TPC is blaming both shear, and dry air for the disrupted convective appeal.
| berrywr |
| (Weather Analyst) |
| Thu Oct 03 2013 09:16 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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I just posted CIMMS Wind Shear analysis over on our Facebook page; it is over 20 knots over the system and there is the presence of an upper level shortwave in place across the Mid-South that extends into the NW Gulf of Mexico and SSEC satellite water vapor confirms there is considerable dry air along a NNE to SSW along that shortwave axis to the west.
| berrywr |
| (Weather Analyst) |
| Thu Oct 03 2013 09:26 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Let me add...those of us in this line of work are always careful as to what type of analysis we're doing. There's NOWCASTING which is exactly what the name implies...right now which is perfect for severe weather because that's happening in real time so every little aspect of a given weather situ is poured over with fine tooth brush. We'd do the same thing as we get within a day of landfall of any of these systems...now, we don't care what's going on on these extreme microscale analysis of vortices, what these clouds look like...none of that matters. What does are these large processes that are on a synoptic scale...big stuff. Tropical Storms/Hurricanes and Upper level Longwaves/Shortwaves are like magnets repelling each other but at the end of the day Longwaves and Shortwaves win out...that's the shear we see on these analysis way up in the atmosphere where these winds will shear the tops off any developing thunderstorms and these systems cannot deepen. These little structural changes undergoing are of so little significance given the overall synoptic pattern. If this was a major storm, oh you bet it would matter and this gov't shutdown would take on a whole new meaning if one of those were out there but it's October. At this point we can't rule out it becoming a hybrid or subtropical as we towards the weekend. Right now it's a sheared system as evident on visible satellite imagery. Check our Facebook page out... its FLHurricane.com there.
| MichaelA |
| (Weather Analyst) |
| Thu Oct 03 2013 11:09 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Yet another sheared system and this continues from the last season as well. It's going to take several years to analyze the mechanics of this and last season (maybe next year, too?). I'll take these weaker, sheared storms over the alternative.
| ralphfla |
| (Weather Watcher) |
| Thu Oct 03 2013 11:23 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Yup Tropical Storm Karen is having trouble with dry air and high wind shear as the storm tries to go north. I think it looks more ragged then early today.
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danielw
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| (Moderator) |
| Fri Oct 04 2013 12:27 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 4th day of the month at 00:09Z
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number & Year: 12L in 2013
Storm Name: Karen (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 28
A. Time of Center Fix: 3rd day of the month at 23:50:38Z
B. Center Fix Coordinates: 23°38'N 88°51'W (23.6333N 88.85W) (View map)
B. Center Fix Location: 445 miles (716 km) to the S (170°) from New Orleans, LA, USA.
C. Minimum Height at Standard Level: 3,091m (10,141ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 34kts (~ 39.1mph)
E. Location of the Estimated Maximum Surface Wind: 46 nautical miles (53 statute miles) to the NW (308°) of center fix
F. Maximum Flight Level Wind Inbound: From 26° at 31kts (From the NNE at ~ 35.7mph)
G. Location of Maximum Flight Level Wind Inbound: 10 nautical miles (12 statute miles) to the WNW (298°) of center fix
H. Minimum Sea Level Pressure: 1001mb (29.56 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 2,442m (8,012ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 16°C (61°F) at a pressure alt. of 2,441m (8,009ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind and Pressure
N. Fix Level: 700mb
O. Navigational Fix Accuracy: 1 nautical mile
O. Meteorological Accuracy: 1 nautical mile
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 50kts (~ 57.5mph) which was observed 26 nautical miles (30 statute miles) to the NE (45°) from the flight level center at 22:37:39Z
Maximum Flight Level Temp: 17°C (63°F) which was observed 10 nautical miles (12 statute miles) to the WNW (298°) from the flight level center
Remarks Section - Additional Remarks...
SONDE SPLASHED WITH SFC WINDS 215 AT 14 KTS
MSLP 999 MB EXTRAP FROM 8000 FT
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danielw
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| (Moderator) |
| Fri Oct 04 2013 12:46 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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2355Z visible and IR Enhanced. SW shear evident.
Image centered at Latitude= 24.77° N Longitude= 88.17° W (X=240 Y=306)
| SirCane |
| (Storm Tracker) |
| Fri Oct 04 2013 02:25 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Karen seems to be firing up right at the Center this evening. This storm is a fighter.
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danielw
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| (Moderator) |
| Fri Oct 04 2013 05:30 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Something strange is going on in the skies above Karen.
I was watching several different WV enhancement on a 3 hour loop.
What had been a V-notch looking mid and upper level Karen became a round mid and upper level. Complete with fibrous outflow fingers from the WSW clockwise to the NE of Karen.
Really strange.
And at the same time a Thunderstorm popped up in the SE Quad and had enough lightning in it to trigger 2 of my Lightning apps. It didn't last long.
| ralphfla |
| (Weather Watcher) |
| Fri Oct 04 2013 05:49 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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NHC noting a Hurricane becoming less likely. High shear in the forecast will prevent more intensification.
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danielw
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| (Moderator) |
| Fri Oct 04 2013 06:01 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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I believe I may now understand what is happening. The Low Level Center and swirl is now near 25N/ 90W. And is now completely out from under the mid and upper levels. It's just to the SE of the 25/90 lat/ long lines.
The mid and upper levels are trying to regenerate thunderstorms and the SE Quad is doing a fair job of that.
The UKMET and Euro Models want to take Karen west. They must be reading the LLCC and lower levels.
While the GFS wants to take Karen to the NE towards Appalachcola AQQ and the Big Bend. I believe this is the mid and upper level side of the storm.
Really messed up system I know, but not entirely impossible.
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danielw
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| (Moderator) |
| Fri Oct 04 2013 06:29 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Center Location, First Pass Inbound
06:19:30Z
24.550N 89.550W
842.1 mb (~ 24.87 inHg) Pressure Level
1,534 meters(~ 5,033 feet) Altitude
1002.3 mb(~ 29.60 inHg) - Min Surface Pressure
From 1° at 3 knots (From the N at ~ 3.4 mph) Flt level wind
20.6°C(~ 69.1°F) Air Temperature
16.7°C(~ 62.1°F) Air Dewpoint
5 knots(~ 5.8 mph) Peak Flt Level wind
12 knots(~ 13.8 mph) SFMR Peak surface wind
0 mm/hr(~ 0 in/hr) Rain rate
7.2 knots (~ 8.3 mph)Estimated Surface wind
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 4th day of the month at 06:52Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 307)
Storm Number & Year: 12L in 2013
Storm Name: Karen (flight in the North Atlantic basin)
Mission Number: 5
Observation Number: 04
A. Time of Center Fix: 4th day of the month at 6:19:30Z
B. Center Fix Coordinates: 24°33'N 89°33'W (24.55N 89.55W)
B. Center Fix Location: 376 miles (606 km) to the S (175°) from New Orleans, LA, USA.
C. Minimum Height at Standard Level: 1,452m (4,764ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 44kts (~ 50.6mph)
E. Location of the Estimated Maximum Surface Wind: 22 nautical miles (25 statute miles) to the ENE (75°) of center fix
F. Maximum Flight Level Wind Inbound: From 155° at 51kts (From the SSE at ~ 58.7mph)
G. Location of Maximum Flight Level Wind Inbound: 43 nautical miles (49 statute miles) to the ENE (62°) of center fix
H. Minimum Sea Level Pressure: 1003mb (29.62 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 1,527m (5,010ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,527m (5,010ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 18°C (64°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind and Pressure
N. Fix Level: 850mb
O. Navigational Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 2 nautical miles
Remarks Section:
Maximum Flight Level Wind: 51kts (~ 58.7mph) which was observed 43 nautical miles (49 statute miles) to the ENE (62°) from the flight level center at 6:05:00Z
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MikeC
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| (Admin) |
| Fri Oct 04 2013 02:49 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Latest track shifts it a bit west, but the forecast confidence in the track details is lower than ever. Chances that Karen becomes a hurricane are very low now, so the hurricane watches may be dropped. The biggest question is if the system makes landfall on the tip of Louisiana or not, or if what is suggested by the GFS model occurs when the through approaches.
| scottsvb |
| (Weather Master) |
| Fri Oct 04 2013 02:58 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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If and when Karen does turn east....she has a good chance of being a hurricane Saturday night as she starts moving ENE or NE...this also depends though if she stays on more of a ENE direction cause she will be over water longer and less influenced by the gulf coast. Question really will be landfall on Sunday or Monday on where she comes inland.....near Pensacola or Big Bend.
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MikeC
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| (Admin) |
| Fri Oct 04 2013 08:33 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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A recent recon vortex message notes the center may be re-forming South and Southeast of the current center, which may change the forecast track quite a bit at 5.
| Lamar-Plant City |
| (Storm Tracker) |
| Fri Oct 04 2013 09:06 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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I am intrigued by the most recent HWRF run. Is that a reliable model....I don't remember? I know a local Met uses it a fair amount in his forecasts.
HWRF 12Z run
| ralphfla |
| (Weather Watcher) |
| Sat Oct 05 2013 12:03 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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after a burst of deep convection near and east of the center earlier
this afternoon...the low-level center of Karen is again exposed
| ralphfla |
| (Weather Watcher) |
| Sat Oct 05 2013 12:12 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Quote:
I am intrigued by the most recent HWRF run. Is that a reliable model....I don't remember? I know a local Met uses it a fair amount in his forecasts.
HWRF 12Z run
When a track of a storm is made it is not made by 1 model it is combo. There is always going to be 1 that has it going more west and 1 having it go more east to pick out the 1 from the 12z Hwrf is just 1 of many the GFDL has it way more to the west and does as good or better but lol
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danielw
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| (Moderator) |
| Sat Oct 05 2013 06:06 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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I'm going to go out on a limb here and say that I think the EXTRAP model and the Satellites have a really good handle on Karen's Track.
At this time, 0130 AM EDT Saturday Oct 5th the LLCC is moving near 290 degrees.
That's just north of due West. EURO and UKMET camp.
| ralphfla |
| (Weather Watcher) |
| Sat Oct 05 2013 08:35 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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the
winds are gradually decreasing. On this basis...the initial
intensity has been lowered to 40 knots in this advisory. Tropical
storms rarely recover after being strongly damaged by
shear...especially if the environment is as dry as it is over the
western Gulf of Mexico.
i think we can say Good Bye to this storm
| OrlandoDan |
| (Weather Master) |
| Sat Oct 05 2013 06:39 PM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Surprisngly, visible sat shows convection wrapping back close to the LLCOC.
| ralphfla |
| (Weather Watcher) |
| Sun Oct 06 2013 04:58 AM |
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Re: Tropical Karen forms in Southern Gulf, Hurricane & Tropical Storm Watches Issued
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Karen has essentially remained stationary for the last several hours
and that lack of motion...coupled with increasing upper-level winds
ahead of an eastward-moving deep-layer trough...has increased the
shear significantly across the cyclone. The result is that
convection has weakened and become displaced well to the east and
southeast of the low-level circulation center. Satellite
classifications from TAFB supported keeping Karen as a borderline
tropical storm at 00z...but the lack of convection near the center
since then requires a downgrade to depression status at the 03z
advisory time. Given that the vertical wind shear is forecast to
get even stronger over the next 2 days...re-strengthening back to
tropical storm status is not likely...especially since the
mid-levels of the troposphere will become increasingly drier
Not going back to a storm will be lucky to hold onto a depression