Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Mon Sep 02 2013 01:12 AM |
Gabrielle Weakens South of Puerto Rico. Heavy Rains Continue.
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12:30 PM EDT Update 5 September 2013
Gabrielle has been downgraded to a depression, and her prospects look uncertain, at best.
Tropical Storm Warnings have been discontinued.
Ciel
10:45 PM EDT Update 4 September 2013
Tropical Storm Gabrielle has formed south of Puerto Rico. Tropical Storm Warnings are up for all of Puerto Rico and eastern parts of the Dominican republic.
Land interaction and other factors will likely keep Gabrielle a Tropical Storm, and the forecast track keeps it well east of the mainland US.
3:45 PM EDT Update 4 September 2013
After weeks of little activity in the tropics the wave southeast of Puerto Rico, 97L looks to be giving it a go for organization and may become a depression or storm tonight or early tomorrow.
Those in Puerto Rico and the Virigin Islands (and other nearby islands) will likely see heavy rainfall and stormy conditions. Most models keep the system well east of the US beyond this.
Recon is currently investigating the area, and the state and existance of the low level circulation center is what will likely be the determining if this is upgraded tonight or not. Based on what recon has found so far, it could be upgraded sooner rather than later.
Original Update
After traveling across the tropical Atlantic for over a week, a tropical wave attained better organization on Saturday and was designated as Invest 97L. Although conditions are currently less than ideal for near-term development, in a few days, as the system moves closer to the Greater Antilles, windshear will decrease and the chances for additional development should increase. This will likely be a slow moving and slow developing system.
ED
{{StormCarib}}
Caribbean Islands Weather Reports
{{StormLinks|Gabrielle|07|7|2013|07|Gabrielle Remnants}}
{{StormLinks|99L|99|8|2013|99|Invest 99L}}
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danielw
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| (Moderator) |
| Mon Sep 02 2013 12:59 PM |
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97L RECON flight plans
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Both the USAFR Hurricane Hunters and NASA's two Global Hawks are tasked to fly 97L over the next few days.
Notice the Tropical Depression notation in the tasking on Day 2.
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1015 AM EDT MON 02 SEPTEMBER 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 03/1100Z TO 04/1100Z SEPTEMBER 2013
TCPOD NUMBER.....13-093
I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (CARIBBEAN)
FLIGHT ONE -- TEAL 70
A. 03/2100Z
B. AFXXX 01DDA INVEST
C. 03/1500Z
D. 16.0N 63.0W
E. 03/2030Z TO 03/2330Z
F. SFC TO 10,000 FT
2. OUTLOOK FOR SUCCEEDING DAY: FIX MISSION @ 04/2100Z NEAR
19N 67W IF SYSTEM DEVELOPS.
3. REMARKS: THE NASA 871 GLOBAL HAWK WILL FLY A 24-HOUR RESEARCH
MISSION OVER THIS SYSTEM
A. NASA 871 TAKE-OFF: 03/1100Z
B. STORM/AREA OF INTEREST: DEPRESSION 97L-
C. DEPARTURE WFF: 1100Z, 03 SEP
D. MISSION DURATION: 24H 00M
E. IP: 1500Z, 03 SEP; 25.0 N, 68.0 W
F. EP: 0600Z, 4 SEPT; 25.0 N, 68.0 W
G. ON-STATION DURATION: 15H 00M
H. ETA WFF: 1100Z, 04 SEPT
I. DROPSONDES DEPLOYED: 0, NO SONDE SYSTEM
J. ALTITUDE: 55,000 TO 65,000 FT
K. PATTERN: RACE TRACK ACROSS REGION OF TD
CIRCULATION IN BOX BOUNDED BY 25.0N 68.0W
17.0N 68.0W, 14.0N 55.0W, 19.0N 52.0W
FOLLOWED BY BUTTERFLY WITHIN REGION OF
CONVECTION ~ 200 NM RADIUS FROM 18.0N 67.5W
4. OUTLOOK FOR SUCCEEDING DAY- BACK TO BACK GH MISSIONS:
A. NA871 LANDING, 1100 Z, 04 SEP
B. NA872 TAKE OFF 1500Z, 04 SEP
| scottsvb |
| (Weather Master) |
| Mon Sep 02 2013 10:16 PM |
Re: 97L RECON flight plans
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Where is the Radar loop time lapse out of Martinique......(sorry for sp) I wish you guys would post it every time there is something coming through the islands
| typhoon_tip |
| (Meteorologist) |
| Tue Sep 03 2013 04:31 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Climatologically, developing tropical cyclones tend to have difficulty passing through the latitude and longitude that 97L currently is ... TPC is citing dry air at mid levels as the culprit for stymied development, this time, but there are other reasons why TCs have difficulties in that region of Caribbean Sea. In short ...if dry air is the only problem, this feature has a better prospect.
The feature looked more impressive on IR imagery for a couple of days prior to entering the eastern Caribbean. However, now more than ever it has acquired a more obvious cyclonic turning to CU and CB clouds, despite there being less overall convective structures. The deep layer profiles of the atmosphere look to remain conducive to further development.
TPC has again upped the hashed region to orange, or medium chance for intensification. There may be some interference by land as this system [probably] turns more NW and then has to pass over the PR archipelago.
John
| MichaelA |
| (Weather Analyst) |
| Wed Sep 04 2013 11:26 AM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Much more circular in appearance this morning SE of Puerto Rico, but there is still a large area of convection just East of the Lesser Antilles. As NHC states, interaction with PR and Hispaniola could be inhibiting to further or rapid development. Just keeping a wary eye on this for now. Long range PR radar does not indicate a closed LLC, though.
| Fairhopian |
| (Weather Watcher) |
| Wed Sep 04 2013 02:10 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Looking at the long range radar out of Puerto Rico, it appears that we may have a closed circulation, with the movement at the center being mostly westward. Anyone concur?
| doug |
| (Weather Analyst) |
| Wed Sep 04 2013 02:13 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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The area to the east and northeast has been catching up and the 2 p.m.TD takes note and states this area will merge with the developing system. This is confirmed by satellite imagery. The question now is will a definite LLC emerge and take over, or will it remain disorganized until it enters the SW ATL. The Shortwave IR would suggest a center somewhere near 16N and 64.5 W, IMO.
| cieldumort |
| (Moderator) |
| Wed Sep 04 2013 02:18 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Recon is flying through 97L now and is presently verifying westerly winds. It's possible we see an upgrade today, and also equally possible that we do not. Most likely, NHC's decision will hang on how well defined the LLC is, given that there is marginal convection .. earlier in the week we had a closed circulation with associated shower and thunderstorm activity, at times abundant, but the circulation was broad, and ultimately opened back up more or less far too quickly to count. Then the showers and storms fell apart in rapid succession.
Lowest pressures so far being found appear to be about 1010mb, with winds generally at or below 25 knots.
Edit: Latest odds given by NHC at 1:59PM EDT were 50%, but closer inspection of the most recent passes (recon is now flying through the southern portions of 97L), coupled with high res satellite loops, leads me to believe the chances for an upgrade today are probably closer to 75%.
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MikeC
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| (Admin) |
| Wed Sep 04 2013 03:52 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Last observation from recon suggests it may have found a center, with the system like it is, it may be named/numbered at 5PM. If I were to bet, I'd say straight to a named system. (Gabriella)
A few more passes from recon will really determine one way or the other, if it doesn't happen at 5PM, before the end of the night is still fairly likely.
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MikeC
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| (Admin) |
| Wed Sep 04 2013 04:15 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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The Automated Tropical Cyclone Forecasting System (ATCF) triggered a renumber, so it looks like TD#7 or Gabriella at 5PM is extremely likely. Those in Puerto Rico and the surrounding islands, heads up.
Beyond that it looks like it will stay well east of the US mainland.
| typhoon_tip |
| (Meteorologist) |
| Wed Sep 04 2013 04:20 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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And as other's have noted, the appearance of a central axis or rotation was hinted by base-reflective/radar; now that has become more clearly defined ... literally just over the last hour of animation.
| doug |
| (Weather Analyst) |
| Wed Sep 04 2013 04:21 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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Looks likely based on the convection firing on the west side of the apparent center, and the beginning of a tap on the moisture from the system to the NE on the north side. This my very well pop today. It will be interesting to see how much influence that other system will have. Some have said it would siphon off the energy from the system, but I think it will be the opposite.
| Hawkeyewx |
| (Weather Analyst) |
| Wed Sep 04 2013 04:52 PM |
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Re: Invest 97L Enters Eastern Caribbean Sea
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The surface flow may not be exceptionally organized yet(~1010 mb is fairly weak), but apparently it's enough to upgrade it. There is certainly a nice, fresh convective blowup near the center, which is also aiding the development of mid-level spin.
| typhoon_tip |
| (Meteorologist) |
| Wed Sep 04 2013 04:58 PM |
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Re: Invest 97L Southeast of Puerto Rico May Develop Very Soon
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Depression designated ...
16.5N 66.2W
30kts, movement WNW, 9mph.
Interestingly, TPC moves the cyclone through the Mona Passage, between PR and the DR. That's actually about 60 nautical miles (less Isle of De Mona) of distance there, and could easily allow the the core of this thing an unimpeded transit through the archipelago.
| typhoon_tip |
| (Meteorologist) |
| Wed Sep 04 2013 06:05 PM |
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Re: Invest 97L Southeast of Puerto Rico May Develop Very Soon
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When I first looked at TD 7, three hours ago on the San Juan base reflectivity, the system was turning cyclonically overall, but the exact center of rotation was hard to pin-point.
Not the case anymore. In fact, it has a dense core of deep convection collocated with a very identifiable and singular axis of rotation. It even has what looks like a spiral band on the southern arc. And, in total, it is spinning faster.
I don't think this system has any intention of hanging out in TD status for very long. Ample oceanic heat content, superb outflow at high altitudes ... and TPCs track is through the Mona Passage, which is obviously not over a mountainous island.
| ralphfla |
| (Weather Watcher) |
| Wed Sep 04 2013 09:04 PM |
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Re: Invest 97L Southeast of Puerto Rico May Develop Very Soon
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You can tell when it has been a slow season when a A Depression that is going to spin back out to sea most likely and not become anything gets this much attention lol
| typhoon_tip |
| (Meteorologist) |
| Wed Sep 04 2013 09:35 PM |
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Re: Invest 97L Southeast of Puerto Rico May Develop Very Soon
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Quote:
You can tell when it has been a slow season when a A Depression that is going to spin back out to sea most likely and not become anything gets this much attention lol
It has been a slower season than many, including the formal prediction agencies, thought it would be, so far... Things can blossom quickly. The season doesn't end until Dec 1. There is plenty of time for a flurry of activity to transpire.
Although the various models do take would-be Gabrielle polarward in a hurry, there are contingencies to that plan that need be considered.
For one, there is a powerful disturbance that may very well be on a developmental curve of its own, not more than a few hundred miles NE of the TD 7. This feature, if it does develop, will likely impact the track of Gabrielle, and do so in unknown ways -- we certainly cannot entrust too much credence to the guidance(s) beyond just 3 days from now given any potential interaction between these features.
| Random Chaos |
| (Weather Analyst) |
| Wed Sep 04 2013 09:45 PM |
| Attachment |
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Re: Invest 97L Southeast of Puerto Rico May Develop Very Soon
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San Juan radar is showing a good band about 30 miles off-shore south of the island, closest points to the band are Guayama and Jauca. Nothing significant closer than that band. IR is showing a very tight, strong circulation.
Looks like the storm just got upgraded to Gabrielle. Nothing from NHC yet, but NRL has already changed it's name. Edit: 15 minutes later, still nothing from NHC. Could be planned for 11pm.
--
Edit: San Juan radar has been upgraded to Dual-Pol radar. Hydrometer classification out of that capability is showing a large amount of possibly hail producing areas in the band just south of Puerto Rico. In the attached image, red indicated hail.
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Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Wed Sep 04 2013 11:35 PM |
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Tropical Storm Gabrielle
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I don't find anything humorous about a slow-moving system that could produce up to 10 inches of rain in the mountains of Puerto Rico and the Dominican Republic with the flash flooding that would result from those heavy rains. Flippant posts have no place on this site.
ED
| Random Chaos |
| (Weather Analyst) |
| Thu Sep 05 2013 06:25 AM |
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Re: Tropical Storm Gabrielle
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St. Croix has gotten the most rain so far, with a narrow region of its SW coast showing Doppler estimates of 4-6" of rain, though most of the island is showing around 2". There is a large region over open water that has seen 10-11"+ of rainfall 55-80 miles SSE of Puerto Rico and 45-60 miles SW of St. Croix. St. Croix is under a flash flood warning.
System looks fairly good on radar, still has a lot of development to do, but it's quite small. Question is, with its proximity to the mountains of Puerto Rico, whether this will disrupt its development at all.
| Hawkeyewx |
| (Weather Analyst) |
| Thu Sep 05 2013 10:32 AM |
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Re: Tropical Storm Gabrielle
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This system is completely decoupled now with the mid-level vort and all the convection east of Puerto Rico and the weak surface vort sw of PR headed toward eastern DR... so it is definitely not a tropical storm. I question whether it should have been named in the first place given the lack of organization from the get-go.
It's a very odd hurricane season. We are at the peak of the season, but disturbances continue to struggle just to reach minimal tropical storm and remain there for more than a day.
| cieldumort |
| (Moderator) |
| Thu Sep 05 2013 11:15 AM |
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Re: Tropical Storm Gabrielle South of Puerto Rico
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With the advantage of visible satellite this morning we can see what is most likely Gabrielle's original LLC trecking off to the WNW, with the mid-level vort proceeding more northerly, perhaps even with an eastward component.
I have no doubt that Gabrielle was a bona fide tropical cyclone, but if a new LLC does not develop much closer to the mid-level vort, and soon, Gabrielle the tropical cyclone may end up having been very short lived.
With all of the dry air around, in some ways this year has reminded me of 2006, although that is perhaps not the best analog. For example, even 2006 had its first hurricane form before September. Being the first week of September without a single hurricane yet this season may allow for the year as a whole to attain as many named storms as widely expected, but creates a challenge of giant proportions for the year to end up with as many hurricanes as forecast.
Now that Garbrielle has decoupled, it appears that the separate area of disturbed weather to her northeast is successfully siphoning off convection, and enhancing its mid to lower level vorticity. While it could be difficult given close proximity, there is clearly an increasing chance that this other disturbance eventually becomes a new tropical cyclone that persists in disrupting Gabrielle, possibly to the point of replacing her as the sole TC in that immediate region.
At present, a new LLC will probably attempt to form underneath the deeper convection hanging with the MLC, but for any new LLC to become established, the old LLC needs to continue scooting out of the way, and the fairly large and well organized cyclonic envelop associated with it would then need to start falling apart at at good clip.
An alternative, but perhaps somewhat less likely solution where Gabrielle could stay alive, would be that no new LLC forms closer to or within the detatched mid level vort, with her now nearly naked LLC to continuing west-northwest, just over the DR or through the archipelago, slowly firing up all new organized convection along the way, or at least at some point in the future.
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danielw
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| (Moderator) |
| Thu Sep 05 2013 02:14 PM |
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TD Gabrielle and 99L
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Gabrielle has decoupled and is moving nw over Hispaniola.
RECON is enroute to INVEST 99L in the SW GOM.
Very strange season so far. By the way Duluth,MN had 43 degrees this morning while at the same time it was snowing on the SE side of Hudson Bay,Canada
Weird
| Random Chaos |
| (Weather Analyst) |
| Fri Sep 06 2013 12:26 AM |
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Re: TD Gabrielle and 99L
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It has weakened to a remnant low. Nothing organized left, though still a lot of rain coming out of the system. Flash Flood warning up for St John and St Thomas currently.
Very strange season.