Forecast for 92L: dissipation by Friday

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

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 367 - 317

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30Blog Index

367. amd
Technical Paper on WindSat

Member Since: Posts: Comments:
357:

You're joking right?

That oil spill is nowhere near big enough to even matter in terms of climate change.

Heck, there are 4000 other wells in the Gulf alone, and we are burning their fuel as fast as it comes in, well, 25% of it anyway. The other 75% of the oil we use goes into plastic.

Anyway, we use 20 million barrels of oil per day in America, and only 25% of that is for "Energy".
Member Since: Posts: Comments:
Quoting btwntx08:

well he is already reading the tropics wrong also i dont need to calm im not yelling hes just worng about the tropics


Actually Rob, you do need to calm down.
Member Since: Posts: Comments:
I think Invest 92L will take much of this path:

Member Since: Posts: Comments:
Quoting IKE:
345...you need to calm down.

well he is already reading the tropics wrong also i dont need to calm im not yelling hes just worng about the tropics
Member Since: Posts: Comments:
362. ryang
Can anyone post the link to the 12z NOGAPS?
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
I don't think you fit into the category of StormW as you are telling me that WindSAT does not measure surface winds. Poof!

It does measure the surface winds..but if the winds are just above the surface..it will see those. All 92L is a weak surface trough with a midlevel center. What you see as a LLC is a vortex that many systems have..especially weak Tropical storms when they have vortexs spin out. This is my last post on this matter. I need a drink! ugh!
Member Since: Posts: Comments:
Awkward Silence in the blog...
Member Since: Posts: Comments:
12z CMC shows 92L's remnants making it to the Gulf of Mexico as a still recognizable trough.
Member Since: Posts: Comments:
Quoting Levi32:


That WindSat pass would not have made the NHC classify it....it was open to the SW on that pass.
Absolutely.
Member Since: Posts: Comments:
What long term effects will the oil spill have on climate change? I haven't seen any info on this as of yet.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Noticeable. Also, cloud tops have warmed, a sign of weakening.



its okay, he has his wall up. It'd be funny if he had a wall on each side, with -90 °C cloud tops to fight the shear.
Member Since: Posts: Comments:
Quoting scottsvb:


I know exactly what it is and if the NHC went by this reading.. why dont we have a TD then? Cause there is not a TD out there to be classified.
Look I'm not on here to argrue tropics with a 13 year old kid (if thats how old you say you are) I post up whats happening and why its happening. You dont have to accept the truth. I wont be always 100% correct also...but meteorology isnt about websites,maps,sat views and weather models. There are other dynamics that come into play. All in all, people should learn from what I, StormW,Weather456,hurricane23,even Levi is generally a good guy. We all make bad judgements also,but instead of challenging, try to figure out why we see things and tell ya whats happening.
I don't think you fit into the category of StormW as you are telling me that WindSAT does not measure surface winds. Poof!
Member Since: Posts: Comments:
Quoting scottsvb:


I know exactly what it is and if the NHC went by this reading.. why dont we have a TD then? Cause there is not a TD out there to be classified.
Look I'm not on here to argrue tropics with a 13 year old kid (if thats how old you say you are) I post up whats happening and why its happening. You dont have to accept the truth. I wont be always 100% correct also...but meteorology isnt about websites,maps,sat views and weather models. There are other dynamics that come into play. All in all, people should learn from what I, StormW,Weather456,hurricane23,even Levi is generally a good guy. We all make bad judgements also,but instead of challenging, try to figure out why we see things and tell ya whats happening.


That WindSat pass would not have made the NHC classify it if it accurately depicted the surface winds....it was open to the SW on that pass.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Again, he isn't making a trollish remark such as cursing or profanity, he is speaking about the tropics and I see no reason why not to quote him.


You are aware trolls can use g rated material?
Member Since: Posts: Comments:
Quoting will45:


He is just stating his opinion and everyone here is allowed an opinion
He wasn't stating his opinion he was just blatantly saying that WindSAT does not measure surface winds and their direction.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Are you kidding me, lol? You're telling me that WindSAT doesn't measure surface wind and surface wind directions. Please read this and tell me whether or not WindSAT measures surface winds or not.

Link


I know exactly what it is and if the NHC went by this reading.. why dont we have a TD then? Cause there is not a TD out there to be classified.
Look I'm not on here to argrue tropics with a 13 year old kid (if thats how old you say you are) I post up whats happening and why its happening. You dont have to accept the truth. I wont be always 100% correct also...but meteorology isnt about websites,maps,sat views and weather models. There are other dynamics that come into play. All in all, people should learn from what I, StormW,Weather456,hurricane23,even Levi is generally a good guy. We all make bad judgements also,but instead of challenging, try to figure out why we see things and tell ya whats happening.
Member Since: Posts: Comments:
Quoting FLWeatherFreak91:
The updrafts have collapsed.
Noticeable. Also, cloud tops have warmed, a sign of weakening.

Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
The NHC analyzed a 1014 mb pressure. That's not very low.

Not as impressive as at D-MAX last night, but I've seen plenty of disturbances that look worse.



Pressure is actually re-analyzed at 1011mb with a closed 1012 around it at 12z.

Member Since: Posts: Comments:
Quoting btwntx08:
well he sucks a talking tropics then


He is just stating his opinion and everyone here is allowed an opinion
Member Since: Posts: Comments:
347. IKE
345...you need to calm down.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
The NHC analyzed a 1014 mb pressure. That's not very low.

Not as impressive as at D-MAX last night, but I've seen plenty of disturbances that look worse.

The updrafts have collapsed.
Member Since: Posts: Comments:
well he sucks a talking tropics then
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Are you kidding me, lol? You're telling me that WindSAT doesn't measure surface wind and surface wind directions. Please read this and tell me whether or not WindSAT measures surface winds or not.

Link


"WindSat is designed to demonstrate the capability of polarimetric microwave radiometry to measure the ocean surface wind vector from space."
Member Since: Posts: Comments:
Quoting btwntx08:
im tellin u dont qoute that troll scottsvb he doesnt know nothing
Again, he isn't making a trollish remark such as cursing or profanity, he is speaking about the tropics and I see no reason why not to quote him.
Member Since: Posts: Comments:
im tellin u dont qoute that troll scottsvb he doesnt know nothing
Member Since: Posts: Comments:
Quoting scottsvb:


WindSat is above the surface. Also vis imagry you see is the same. Infact its not showing any NW or SW winds @ all anywhere. If you see them.. post up a close up vis loop and mark where you see this.
Are you kidding me, lol? You're telling me that WindSAT doesn't measure surface wind and surface wind directions. Please read this and tell me whether or not WindSAT measures surface winds or not.

Link
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Did you not see the WindSAT? That just proves that there is a surface low, it's just not closed. Also satellite imagery shows a well-defined LLC.


WindSat is above the surface. Also vis imagry you see is the same. Infact its not showing any NW or SW winds @ all anywhere. If you see them.. post up a close up vis loop and mark where you see this.
Member Since: Posts: Comments:
Quoting kmanislander:
Have to go now. Will be back later.
Later Kman.
Member Since: Posts: Comments:
Have to go now. Will be back later.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting Patrap:
NEXRAD Radar
New Orleans, Echo Tops Range 124 NMI





Pat,
I think that radar has been playing too much Tetris...
CRS
Member Since: Posts: Comments:
Quoting Levi32:


The convergence and divergence products are calculated by using finite differencing of the u and v wind vectors. These vectors primarily come from the satellite cloud motions, what CIMSS calls the "gridded atmospheric motion vector output". However, in data-sparse regions, this missing data is filled in with numerical model data. Low-level clouds obviously cannot be observed underneath strong convection, and thus it is not surprising that the CIMSS convergence product did not depict the situation accurately, as the models would not have shown the small-scale changes that happened underneath the MCC in a short period of time.

Upper divergence is much easier to accurately calculate because the upper clouds, if any are around, are always observable by the satellite because they are above everything else.


Great answer,thanks. I guess the moral of that is don't place too much emphasis on the convergence map in every situation but look for other data to confirm or modify.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
i think the cmc just went to the dark side and is off it may pick it up later
Member Since: Posts: Comments:
Quoting scottsvb:
OK ,, well I posted many times there is no LLC.. its above the surface. Maybe in a few days when this reaches the bahamas-cuba there might be. Right now, pressures are high.
Did you not see the WindSAT? That just proves that there is a surface low, it's just not closed. Also satellite imagery shows a well-defined LLC.
Member Since: Posts: Comments:
Quoting kmanislander:
Levi, a question for you. The Windsat pass shows a very vigorous surface low at a time when the CIMSS convergence map for 6 and 9 hours ago was showing very little surface convergence at all.

I find that odd because the well defined low would be drawing surface winds into the system at the lower levels at a rate that should reflect a stronger signature than seen in the map.

Is this just an algorithm issue with the CIMSS map ?


The convergence and divergence products are calculated by using finite differencing of the u and v wind vectors. These vectors primarily come from the satellite cloud motions, what CIMSS calls the "gridded atmospheric motion vector output". However, in data-sparse regions, this missing data is filled in with numerical model data. Low-level clouds obviously cannot be observed underneath strong convection, and thus it is not surprising that the CIMSS convergence product did not depict the situation accurately, as the models would not have shown the small-scale changes that happened underneath the MCC in a short period of time.

Upper divergence is much easier to accurately calculate because the upper clouds, if any are around, are always observable by the satellite because they are above everything else.
Member Since: Posts: Comments:
Quoting DestinJeff:
Looking at the GFS 850-200 shear forecast, if 92L maintains more of a westerly motion then shear does clear out rather substantially after just 12-24 hrs.

Link



GFS has been showing this for awhile now, and whilethe TUTT is lifting, it is very slowly and not as rapidly as depicted there. In fact...

Member Since: Posts: Comments:
OK ,, well I posted many times there is no LLC.. its above the surface. Maybe in a few days when this reaches the bahamas-cuba there might be. Right now, pressures are high.
Member Since: Posts: Comments:
Quoting Floodman:
There's a lot of good, level-headed thought in here this morning, interpsersed with some real and intense wishcasting...


to quote David Byrne: "same as it ever was, same as it ever was."
Member Since: Posts: Comments:
I think 92L has slowed down quite a bit
Member Since: Posts: Comments:
NEXRAD Radar
New Orleans, Echo Tops Range 124 NMI



Member Since: July 3, 2005 Posts: 427 Comments: 129411
There's a lot of good, level-headed thought in here this morning, interpsersed with some real and intense wishcasting...
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Current Conditions

Uptown, New Orleans, Louisiana (PWS)
Updated: 1 min 57 sec ago
Mostly Cloudy

91.9 °F

Mostly Cloudy
Humidity: 65%
Dew Point: 78 °F
Wind: 2.6 mph from the North
Wind Gust: 6.3 mph
Pressure: 30.15 in (Falling)

Heat Index: 108 °F

Visibility: 7.0 miles
UV: 6 out of 16
Pollen: 4.40 out of 12
Pollen Forecast new!
Clouds:
Scattered Clouds 2500 ft
Mostly Cloudy 25000 ft
(Above Ground Level)
Elevation: 20 ft

Man...a Huge Tower to 50 K to my EnE and itsa making a lotta racket.

Member Since: July 3, 2005 Posts: 427 Comments: 129411
Levi, a question for you. The Windsat pass shows a very vigorous surface low at a time when the CIMSS convergence map for 6 and 9 hours ago was showing very little surface convergence at all.

I find that odd because the well defined low would be drawing surface winds into the system at the lower levels at a rate that should reflect a stronger signature than seen in the map.

Is this just an algorithm issue with the CIMSS map ?
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Member Since: Posts: Comments:
320. IKE
12Z CMC has just about dropped 92L.
Member Since: Posts: Comments:
319. IKE
This may have been posted earlier...

SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
1130 AM EDT WED JUN 16 2010

.SYNOPSIS...A TROPICAL WAVE ENTERING THE E CARIBBEAN THIS
AFTERNOON WILL CONTINUE W THROUGH THE CENTRAL PORTION THU
THROUGH SAT REACHING THE W WATERS SUN AND SUN NIGHT. LOW PRES
NEAR 15N51W WILL WEAKEN TO A TROUGH AND MOVE NW PASSING THROUGH
THE LEEWARDS FRI. ANOTHER TROPICAL WAVE WILL APPROACH 55W ON
SUN.
Member Since: Posts: Comments:
Quoting Levi32:


Was talking about visible imagery not the WindSat pass.
Oh, my bad.
Member Since: Posts: Comments:
Quoting WinterAnalystwx13:
June 15 - Invest 92L struggles with shear.

June 17 - Invest 92L is discontinued by the NHC

June 25 - Remnants of Invest 92L orgainze rapidly, NHC breaks out the yellow crayon.

June 28th - TD #1 forms from the remnants of 92L

June 30 - TD #1 becomes TS Alex

July 1 - Alex strengthens to a 50 m/h storm, slams into LA/MS.


Wow- that would be an oily scenario.
Member Since: Posts: Comments:

Viewing: 367 - 317

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30Blog Index

Top of Page

About

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

Local Weather

Overcast
45 °F
Overcast