Forecast for 92L: dissipation by Friday

By: Dr. Jeff Masters , 2:17 PM GMT on June 16, 2010

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A low pressure system about 700 miles east of the Lesser Antilles Islands, Invest 92L, was near tropical depression status early this morning, but is currently weakening. Infrared satellite loops show the disturbance's heavy thunderstorm activity has decreased markedly in the past few hours, with the cloud top temperatures warming noticeably, indicating that 92L's thunderstorms are no longer pushing as high into the atmosphere. Water vapor satellite loops show that the storm is surrounded on all sides by dry air, though there is a region of moister air in front of it that 92L will encounter on Thursday. Wind shear as diagnosed by the University of Wisconsin is near 20 knots, though the SHIPS model is diagnosing the shear at a higher 25 - 30 knots. This high shear is pushing 92L's heavy thunderstorm activity to the east side of the center of circulation, and the center will probably become exposed to view late this morning. Had 92L been able to maintain the heavy thunderstorm activity it had early this morning for 12 or so hours, it could have been classified as a tropical depression. However, classification as a TD requires persistent heavy thunderstorm activity, typically interpreted to mean 12 hours of consistent heavy thunderstorm activity, and 92L did not meet that criterion.


Figure 1. Morning satellite image of Invest 92L. Image credit: NOAA.

The forecast for 92L: dissipation
Wind shear is the main story in the forecast for 92L, as a band of very high wind shear of 20 - 50 knots lies to the northwest of the storm. The current expected track of 92L carries it into this band of high wind shear, and the SHIPS model (based on the GFS model) is predicting that the shear will remain in the 25 - 30 knot range through Friday. Other models predict higher shear levels. It is likely that the high shear, combined with the dry air surrounding the storm, will destroy 92L by Friday. The National Hurricane Center is giving 92L a low (10% chance) of developing into a tropical depression by Friday morning, and this is a reasonable forecast. It is likely that 92L will bring heavy rain showers and wind gusts up to 35 mph on Friday to the Lesser Antilles Islands. I don't expect 92L to be organized enough to cause flooding problems to any of the islands in its path. None of our reliable global computer models develop 92L into a tropical depression. The rest of the tropical Atlantic is quiet, and none of the reliable computer models is calling for tropical cyclone development in the Atlantic over the next seven days.

Is the formation of 92L a harbinger of an active hurricane season?
According to the Hurricane FAQ, Goldenberg (2000) found that during the period 1944 - 1999, formation of a named storm in the tropical Atlantic south of 22°N and east of 77°W during June and July was a harbinger of at least an average season, and in many cases an above average season. The formation of a storm in this region during June or July is one factor the NOAA and Colorado State University seasonal hurricane forecast teams have used in the past as a predictor for an active season in their early August forecasts. Now, 92L didn't make it to named storm status, though it was pretty close to being a tropical depression. However, the near-formation of 92L into a tropical depression, is, in my mind, a clear harbinger that we can expect a severe hurricane season this year. It's very rare to have a development like 92L in that portion of the tropical Atlantic this early in the season. The lower than average wind shear and higher than average SSTs that helped 92L get organized are more likely than not to carry over into the main portion of hurricane season, giving us a much more active hurricane season than normal.


Figure 2. Synthetic Aperture Radar (SAR) image of the oil spill taken at 7:51 am EDT Tuesday June 15, 2010, by the Canadian Radarsat-1 satellite, operated by MDA GeospatialServices of Richmond, Canada. A large amount of oil was present on the Florida Panhandle coast near Pensacola, and was headed east towards Panama City. Image credit: Center for Southeastern Tropical Advanced Remote Sensing, University of Miami Rosenstiel School of Marine and Atmospheric Science. SAR images have a resolution of 8 - 50 meters, and can be taken through clouds and precipitation.

Oil spill wind and ocean current forecast
Light and variable winds less than 10 knots will blow in the northern Gulf of Mexico for the next five days, according to the latest marine forecast from NOAA. The winds will tend to have a westerly component for the most part, which will maintain a slow (1/4 mph) eastward-moving surface ocean current that will transport oil eastwards along the Florida Panhandle coast, according to the latest ocean current forecast from NOAA's HYCOM model. These winds and currents may be capable of transporting oil east past Panama City, Florida to Cape San Blas by Monday. Oil will continue to threaten the coasts of Louisiana, Alabama, and Mississippi for the remainder of the week as well, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The long range 8 - 16 day forecast from the GFS model indicates a typical summertime light wind regime, with winds mostly blowing out of the south or southeast. This wind regime will likely keep oil close to the coastal areas that have already seen oil impacts over the past two weeks.

NOAA has lauched a great new interactive mapping tool that allows one to overlay wind forecasts, ocean current forecasts, oil location, etc.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA has lauched a great new interactive mapping tool that allows one to overlay forecasts and oil location observations
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

I'll have an update on Thursday.

Jeff Masters

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1467. Claudette1234
1:54 PM GMT on June 17, 2010


TD THREE was declared 1st advisory will be at 11AM EDT by NHC
Member Since: July 21, 2009 Posts: 0 Comments: 552
1466. cg2916
1:48 PM GMT on June 17, 2010
NEW BLOG!!!
Member Since: December 21, 2007 Posts: 13 Comments: 3046
1465. AllStar17
1:43 PM GMT on June 17, 2010
Member Since: June 29, 2009 Posts: 13 Comments: 5315
1464. AllStar17
1:43 PM GMT on June 17, 2010
Quoting MiamiHurricanes09:
It's dead. All the convection associated with it is TUTT enhanced, if the TUTT weren't there 92L would not be able to sustain the convection by itself.


If the TUTT weren't there, the shear would not be there either, and it would have developed.
Member Since: June 29, 2009 Posts: 13 Comments: 5315
1463. sporteguy03
1:36 PM GMT on June 17, 2010
Quoting IKE:
UKMET did a good job in 2009 with the numbers. If they go with 20 in 5 months...that's 4 per month on average.

92L looks to be moving west and is heading south of PR, for now.


UKMET forecast I'm pretty sure uses the ECMWF in the forecasting, can you imagine having 27 systems starting in July? If it is 20 that is still very high.

Hope it is wrong though, although that seems wishful thinking at best at this point.

2009 verfication: http://www.metoffice.gov.uk/corporate/pressoffice/2009/pr20091216a.html
Member Since: July 7, 2005 Posts: 0 Comments: 5415
1461. nrtiwlnvragn
1:25 PM GMT on June 17, 2010
New Blog... everybodys favorite topic :(
Member Since: September 23, 2005 Posts: 14 Comments: 11274
1460. scott39
1:24 PM GMT on June 17, 2010
Goodmorning, Regardless if the TUTT is keeping 92L on life support, isnt it still something to watch next week when its remnants get in the GOM and will be in a favorable enviroment? If 92L can make it thru 40knt-50knt wind shear with or without life support,this concens me for the GOM next week.
Member Since: June 13, 2009 Posts: 0 Comments: 6887
1459. SLU
1:24 PM GMT on June 17, 2010
Quoting pottery:

Time to check that all the drainage channels around your house are in good shape!


certainly!
Member Since: July 13, 2006 Posts: 13 Comments: 5356
1457. stillwaiting
1:20 PM GMT on June 17, 2010
so 92L was never a TD,but the area designated as the 92E is????,makes me wonder if some of the mets at the NHC are on point...makes no sense to me,92L had a defined surface low,eastpacs TD1 doesn't even have that!!!
Member Since: October 5, 2007 Posts: 20 Comments: 4970
1454. hercj
1:14 PM GMT on June 17, 2010
Quoting pottery:

Departing for where?

Back to Tampa.
Member Since: September 5, 2009 Posts: 0 Comments: 319
1453. MiamiHurricanes09
1:14 PM GMT on June 17, 2010
Quoting btwntx08:

850 mb vitocity meaning it has something on the surface
Yes but it doesn't show organization. If you look at the actual run it shows a very very weak system (remnants of 92L) entering the GOM. But if you look at the 850 millibar vorticity it looks like a tropical storm.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1451. pottery
1:13 PM GMT on June 17, 2010
Quoting hercj:

Pottery, where are you located? I am currently on St Croix but scheduled to depart this evening.

Departing for where?
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1449. pottery
1:12 PM GMT on June 17, 2010
Quoting hercj:

Pottery, where are you located? I am currently on St Croix but scheduled to depart this evening.

Trinidad, 11N 61W
Out....
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1448. PanhandleChuck
1:11 PM GMT on June 17, 2010
92L is D.R.T. (Dead Right There). Need to be more concerned about the GOM within the next week or so. IMHO
Member Since: May 13, 2008 Posts: 0 Comments: 1414
1447. pottery
1:11 PM GMT on June 17, 2010
Quoting MiamiHurricanes09:
Anything for the divine potter of the Calabash tree.

heheheheh
BBL.
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1446. hercj
1:11 PM GMT on June 17, 2010
Quoting pottery:

Thanks.

Pottery, where are you located? I am currently on St Croix but scheduled to depart this evening.
Member Since: September 5, 2009 Posts: 0 Comments: 319
1444. MiamiHurricanes09
1:10 PM GMT on June 17, 2010
Quoting pottery:

Thanks.
Anything for the divine potter of the Calabash tree.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1442. MiamiHurricanes09
1:09 PM GMT on June 17, 2010
Quoting stormpetrol:
Convection starting to fire near the center of 92L, might make a comeback.
Like I said previously all the convection associated with 92L is TUTT enhanced.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1441. MiamiHurricanes09
1:08 PM GMT on June 17, 2010
Quoting NotCircumventing:
Latest CMC develops 92L and sends it into the BOC at the end ... with another system in the Carribbean
I suggest for you to not use those maps as they only show vorticity and not organization.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
1440. pottery
1:06 PM GMT on June 17, 2010
Quoting MiamiHurricanes09:
I haven't seen the model run but it considering the time-frame it appears so. It should start to move more northerly before crashing into south America though.

Thanks.
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1438. stormpetrol
1:05 PM GMT on June 17, 2010
Convection starting to fire near the center of 92L, might make a comeback.
Member Since: April 29, 2007 Posts: 0 Comments: 8010
1437. MiamiHurricanes09
1:04 PM GMT on June 17, 2010
Quoting pottery:

In that graphic--- 138 hrs.
the area shown off the Guyana's, is that the wave that is on Africa now?
If so, it remains well embedded in the ITCZ all the way across.
I haven't seen the model run but it considering the time-frame it appears so. It should start to move more northerly before crashing into south America though.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1434. MiamiHurricanes09
1:01 PM GMT on June 17, 2010
Quoting CaribBoy:
92L just dont wanna DIE.
It's dead. All the convection associated with it is TUTT enhanced, if the TUTT weren't there 92L would not be able to sustain the convection by itself.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1433. pottery
1:00 PM GMT on June 17, 2010
Quoting NotCircumventing:
Energy from 92L over the Keys @138

In that graphic--- 138 hrs.
the area shown off the Guyana's, is that the wave that is on Africa now?
If so, it remains well embedded in the ITCZ all the way across.
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1432. MiamiHurricanes09
12:59 PM GMT on June 17, 2010
Quoting NotCircumventing:
something I notice on the Low Cloud Product is how the shear appears more severe north of the blue line I have drawn, while the LLC (or whatever is left of it) is south of that line ...

if 92L maintains a westerly fwd motion, while shear lifts North, then it remains a feature worth watching as it gets into the NE Carribbean

If 92L remains over the Greater Antilles I doubt that it will develop as the equatorial ridge is not wide enough to push the TUTT so north that 92L will not be affected.

GFS 06z 48 hours
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1431. CaribBoy
12:58 PM GMT on June 17, 2010
92L just dont wanna DIE.
Member Since: October 6, 2007 Posts: 0 Comments: 6423
1430. PanhandleChuck
12:58 PM GMT on June 17, 2010
Quoting KEEPEROFTHEGATE:


GREAT TUNE


One of their best KOG
Member Since: May 13, 2008 Posts: 0 Comments: 1414
1429. MiamiHurricanes09
12:56 PM GMT on June 17, 2010
We have another EPAC TD.

invest_RENUMBER_ep922010_ep032010.ren
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1426. pottery
12:49 PM GMT on June 17, 2010
Quoting SLU:


What's for sure is that a series of stronger than normal tropical waves for June are expected to march across the Atlantic during the next 7 - 10 days in an environment that appears to be reasonable for development with the reduction in wind shear. Heavy rains in store for the Antilles in that period.

Time to check that all the drainage channels around your house are in good shape!
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1425. SLU
12:48 PM GMT on June 17, 2010
Quoting stoormfury:
the tropical wave in the catl near 35w is showing some migration to the 10 deg lat line. there is some vorticity there. it could be very possible that there could be a pertabation from the wave which is embedded inthe ITCZ. some of the models are hinting of development from this area which will go on to affect barbados and the southern windwards islands some time next week.


What's for sure is that a series of stronger than normal tropical waves for June are expected to march across the Atlantic during the next 7 - 10 days in an environment that appears to be reasonable for development with the reduction in wind shear. Heavy rains in store for the Antilles in that period.
Member Since: July 13, 2006 Posts: 13 Comments: 5356
1423. pottery
12:46 PM GMT on June 17, 2010
Another wave to come off Africa tomorrow, pretty far north and covers a large area.
The Tropics are very moist, all the way to the East Pacific.
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1421. KEEPEROFTHEGATE (Mod)
12:42 PM GMT on June 17, 2010
Member Since: July 15, 2006 Posts: 175 Comments: 54847
1420. pottery
12:37 PM GMT on June 17, 2010
Quoting stoormfury:
the tropical wave in the catl near 35w is showing some migration to the 10 deg lat line. there is some vorticity there. it could be very possible that there could be a pertabation from the wave which is embedded inthe ITCZ. some of the models are hinting of development from this area which will go on to affect barbados and the southern windwards islands some time next week.

Yes, I am seeing that.
There is a lot of rainfall in that right now, and plenty of moisture all over this area.
Member Since: October 24, 2005 Posts: 0 Comments: 24650
1419. stoormfury
12:35 PM GMT on June 17, 2010
the tropical wave in the catl near 35w is showing some migration to the 10 deg lat line. there is some vorticity there. it could be very possible that there could be a pertabation from the wave which is embedded inthe ITCZ. some of the models are hinting of development from this area which will go on to affect barbados and the southern windwards islands some time next week.
Member Since: August 22, 2006 Posts: 0 Comments: 2720
1418. KEEPEROFTHEGATE (Mod)
12:24 PM GMT on June 17, 2010
Member Since: July 15, 2006 Posts: 175 Comments: 54847
1417. CyclonicVoyage
12:24 PM GMT on June 17, 2010
Quoting IKE:
I don't see a LLC left with 92L. Just a broad cyclonic turning.


Looking at visible this morning, your correct. I got up to darned early this morning.
Member Since: January 30, 2010 Posts: 0 Comments: 3259

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.