Unusually well-organized 92L disturbance may become a tropical depression

By: Dr. Jeff Masters , 2:14 PM GMT on June 14, 2010

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Invest 92L, a remarkably well-developed African tropical wave for so early in the season, is midway between Africa and the Lesser Antilles Islands. Infrared satellite loops show a modest area of heavy thunderstorms along the north side of 92L's center of circulation, and the storm's heavy thunderstorms activity appears to be slowly increasing in intensity and areal coverage. Upper-level outflow is apparent to the west and north of 92L, and the outflow has been gradually improving this morning. Visible satellite loops do not show much in the way of low-level spiral bands, and my current take from the satellite imagery is that 92L is slowly organizing, and will not become a tropical depression any earlier than 11pm EDT tonight (Monday.) A 4:27 am EDT pass from the WINDSAT satellite saw a partially closed circulation at the surface (open on the south side), with top surface winds of 25 - 30 mph north of the center.


Figure 1. Morning satellite image of Invest 92L (left side of image) and a vigorous new tropical wave that has moved off the coast of Africa (right side.) None of models develop the new tropical wave, but it bears watching.

Sea surface temperatures
Climatology argues against development of 92L, since only one named storm has ever formed between Africa and the Lesser Antilles Islands in the month of June--Tropical Storm Ana of 1979 (Figure 2). However, sea surface temperatures (SSTs) underneath 92L are an extremely high 28°C, and will increase to 29°C by Thursday. In fact, with summer not even here, and three more months of heating remaining until we reach peak SSTs in the Atlantic, ocean temperatures across the entire Caribbean and waters between Africa and the Lesser Antilles are about the same as they were during the peak week for water temperatures in 2009 (mid-September.)

Dry air not a problem for 92L until Wednesday
The disturbance doesn't have to worry about dry air today or Tuesday--Total Precipitable Water (TPW) loops show a very moist plume of air accompanies 92L, and water vapor satellite loops show that the center of 92L is at least 200 - 300 miles from any substantial areas of dry air. As 92L continues to push northwest, though, the SHIPS model is predicting that relative humidity at middle levels of the atmosphere will fall from the current value of about 70%, to 60% on Wednesday. This dry air may begin to cause problems for 92L on Wednesday, especially since wind shear will be increasing at the same time. Tropical cyclones are more vulnerable to dry air when there is substantial wind shear, since the strong winds causing the shear are able to inject the dry air deep into the core of the storm.

Madden-Julian Oscillation
The 60-day cycle of enhanced thunderstorm activity called the Madden-Julian Oscillation is currently favoring upward motion over eastern tropical Atlantic, and this enhanced upward motion helps create stronger updrafts and higher chances of tropical cyclone development.


Figure 2. Tropical Storm Ana of 1979 was the only June named storm on record to form between Africa and the Lesser Antilles Islands.

Wind shear
A major issue for 92L, like it is for most June disturbances, is wind shear. The subtropical jet stream has a branch flowing through the Caribbean and tropical Atlantic north of 10° N that is bringing 20 - 40 knots of wind shear to the region. Our disturbance was located near 10°N, 40°W at 8am EDT this morning, a few hundred miles south of this band of high shear, and is currently only experiencing 5 - 10 knots of shear. This low amount of shear should allow for some steady development of 92L over the next two days as it tracks west-northwest or northwest at 15 mph. The latest run of the SHIPS model is predicting the shear will rise to 20 knots on Wednesday, which may start to cause problems for 92L.

The forecast for 92L
The National Hurricane Center is giving 92L a high (60% chance) of developing into a tropical depression by Wednesday morning, which is a reasonable forecast. The odds of development have increased since yesterday, as the storm has moved considerably to the northwest, away from the Equator. Now it can leverage the Earth's spin to a much greater degree to help get it get spinning. It is quite unusual for a tropical depression to form south of 8°N latitude.

I expect that 92L's best chance to become a tropical depression will come on Tuesday, and the storm could strengthen enough by Wednesday to be named Tropical Storm Alex. The farther south 92L stays, the better chance it has at survival. With the system's steady west-northwest movement this week, 92L will probably begin encountering hostile wind shear in excess of 20 knots by Wednesday, which should interfere with continued development. Several of our reliable models do develop 92L into a tropical storm with 40 - 55 mph winds, but all of the models foresee weakening by Thursday or Friday as 92L approaches the Lesser Antilles Islands and encounters high shear and dry air. I doubt 92L will be anything stronger than a 45 mph tropical storm when it moves through the northern Lesser Antilles Islands on Friday and Saturday, and it would be no surprise if wind shear has destroyed the storm by then. However, as usual, surprises can happen, and the GFS and the SHIPS model (which is based upon the GFS) do indicate that more modest levels of wind shear in the 15 - 20 mph range late this week may allow 92L to stay stronger than I'm expecting. Residents of the islands--particularly the northern Lesser Antilles--should follow the progress of 92L closely, and anticipate heavy rains and high winds moving through the islands as early as Thursday night.

Oil spill wind forecast
There is little change to the oil spill wind forecast for the coming two weeks. Light winds of 5 - 10 knots mostly out of the south or southeast will blow in the northern Gulf of Mexico all week, according to the latest marine forecast from NOAA. These winds will keep oil near the coast of Louisiana, Alabama, Mississippi, and the extreme western Florida Panhandle, 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.

Jeff Masters

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3091. hercj
Quoting aquak9:


The Gulf of Mexico oil-containment unit that BP is presently using.

Ok that is what I thought. I am of the mind that Costner's machine is on the right track. However, I am also of the mind that whom ever will perfect such a device will claim the rights to the recovered oil and therefore will profit mightily and then we can hate them too.
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GFS Windshear forecast

96h


120h
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Quoting 900MB:
Looks like we are back to blob watch mode.

Anyone have a decent shot of the wave behind 92l?

What is everyone making of the convection in the Gulf?

I noticed that feature this morning, but i think it's too far out there, we should know more by tomorrow or Thursday.
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3088. Patrap
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92 Peek-A-Boo
Member Since: July 12, 2007 Posts: 0 Comments: 6049
Quoting DestinJeff:


The efforts to prevent oil into the bay may be heroic, but I'm not sure they will be able to sustain a successful effort long enough to keep it out entirely.

Not saying that nothing should be done, but without some resolution further out in the GOM I don't see long-term success. Very, very sad.


There is alot of discussion on this by some very intelligent people.They can fill it in with sand.Simple solution.Its due for a dredging anyway.Drege it back out after the oil threat is over.
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3084. cg2916
I'm going ahead and saying it:

RIP 92L
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It looks like invest 92 finally made that westerly turn as Storm W was predicting.

It doesn't look good for the system at the moment, what when it comes to mother nature, you can't really write it off completely either, regardless i think the northern islands from Guadalupe to the Puerto Rico can at least expect some rain from the this tropical wave.
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3082. 900MB
Looks like we are back to blob watch mode.

Anyone have a decent shot of the wave behind 92l?

What is everyone making of the convection in the Gulf?
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3081. aquak9
Quoting hercj:

Just because I'm curious, what mess do you refer to?


The Gulf of Mexico oil-containment unit that BP is presently using.
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3080. hercj
Quoting ricderr:
Hilarious how Costner can be described as a circus clown when by monetary standards all he needed to do was live fat and happy off his movie earnings. Instead, he invested his money and time into creating something that bettered our planet, making it safer for you and I and our children to live in. To help ensure our surival as a species. If more thought a bit less selfishly we wouldn't be in this mess presently.

Just because I'm curious, what mess do you refer to?
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3079. aquak9
Quoting ElConando:


This is worse than waterworld.


actually, I saw a test-run video of the machine. It's simple, really, using centrifugal force to seperate oily water, into drinkable water, and oil. One tube pumping nasty stuff in, two tubes coming out- one of oil, one of water.
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3078. ackee
any one thinks that shear will be major factor this seasons ? one would of thought shear level would be falling given changing over to La nina any thoughts
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Does anyone have any data, maps, or websites, other than the navy's of what the projected max sea surface temperatures are going to look like come round september?
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3076. Patrap
12z Late Cycle NHC model tracks
Invest92


Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)


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3075. Patrap

NASA Team Captures Hayabusa Spacecraft Reentry



A group of astronomers from NASA, the Japan Aerospace Exploration Agency (JAXA) and other organizations had a front row seat to observe the Hayabusa spacecraft's fiery plunge into Earth's atmosphere. The team flew aboard NASA's DC-8 airborne laboratory, packed with cameras and other imaging instruments, to capture the high-speed re-entry over an unpopulated area of central Australia.
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3074. scott39
Hey Yall look at the current Sat loop.
Member Since: June 13, 2009 Posts: 0 Comments: 6861
3073. ricderr
Hilarious how Costner can be described as a circus clown when by monetary standards all he needed to do was live fat and happy off his movie earnings. Instead, he invested his money and time into creating something that bettered our planet, making it safer for you and I and our children to live in. To help ensure our surival as a species. If more thought a bit less selfishly we wouldn't be in this mess presently.
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hey germemiguel cay you show me more after 72hours haw is the shear
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Well 92L didn't make it, but I firmly believe as well as other bloggers and METS on other sites that at one time yesterday morning from 5 a.m. - 8 a.m., 92L became a Tropical Depression.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
GFS Windshear forecast
24h


48h


72h
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Quoting ElConando:
African blob still there producing thunderstorms. Lets see what it is like by the weekend.

will have to keep an eye one it
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Quoting RecordSeason:
"BP enlists help from Kevin Costner." - CNN.

Sad, sad that a multi-Billion dollar company needs help from glorified hollywood circus clowns.

So, are they going to use his machine? Or do they just need acting lessons for Tony Hayward?


This is worse than waterworld.
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Quoting RecordSeason:
"BP enlists help from Kevin Costner." - CNN.

Sad, sad that a multi-Billion dollar company needs help from glorified hollywood circus clowns.

So, are they going to use his machine? Or do they just need acting lessons for Tony Hayward?


Breaking photos from the Gulf of Costner testing his machine.

Member Since: September 22, 2005 Posts: 18 Comments: 2343
Quoting MiamiHurricanes09:
I am no longer expecting 92L to develop into a tropical depression due to its proximity to a band of shear to the north of the system. 92L continues movement towards the northwest and could possibly dissipate over the next 72 hours and could possibly become a naked swirl in just 48 hours. I think there is a low chance, about 10%, of 92L becoming a tropical depression.

I do have to say that 90L was a tropical depression late Saturday night and all of Sunday as an ASCAT pass proved that there was a closed low and there was exceedingly well satellite presentation.

I expect 92L to become TD #1 in post season analysis.

I agree completely
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African blob still there producing thunderstorms. Lets see what it is like by the weekend.
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You all have a great day. I am out.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting ElConando:
keep an eye on the GOM, just one for now and two next week.


I wonder if conditions will alow the blob to work its energy to the surface-it seems to be confined-not moving at all.
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Quoting kmanislander:


Sorry but I am not going there again on that discussion. Enough was said on that topic last night and reopening it will not change anyone's opinion one way or the other.
Quoting DestinJeff:


09, if you'd like to rehash this discussion please click back how ever many pages to last night ... there are at least 200 comments regarding this topic.
Sorry, didn't mean to start the topic/discussion again, I was just stating my opinion.
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keep an eye on the GOM, just one for now and two next week.
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3058. IKE
Quoting ElConando:


I mess that word and many others. The only reason I come out coherent on here is because of firefox. LOL


Me too.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
3057. IKE
DESTIN — Okaloosa County isn’t taking oil spill orders any more.

County commissioners voted unanimously to give their emergency management team the power to take whatever action it deems necessary to prevent oil from the Deepwater Horizon spill from entering Choctawhatchee Bay through the East Pass.

From here.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting hurricane23:


Its early brother worked 15hrs yesterday. 92L never really established or sustained deep convection near its coc. Hopeing that TUTT sits there through oct.


I mess that word and many others. The only reason I come out coherent on here is because of firefox. LOL
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3054. Patrap
BP Engineer Called Deepwater Horizon 'Nightmare Well' Days Before Blast, Oil Spill




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Quoting MiamiHurricanes09:
I consider 92L to be more than a potent wave as ASCAT from a few days ago concluded that there was a closed low, and convection was exceedingly defined at the time of that ASCAT pass.


Sorry but I am not going there again on that discussion. Enough was said on that topic last night and reopening it will not change anyone's opinion one way or the other.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting Chicklit:

um, big oil?


Unfortunately for the US a foreign oil company did this. Can't really shake them too much unless UK really wants to. Which it seems not likely to happen.
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Quoting ElConando:
Quite or Quiet? People mess up that word a whole lot.


Its early brother worked 15hrs yesterday. 92L never really established or sustained deep convection near its coc. Hopeing that TUTT sits there through oct.
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Quoting kmanislander:


Good morning Pat. I agree. Like I posted yesterday morning you don't throw climatology out the window just because you have a potent wave in the deep tropics early in the season.
I consider 92L to be more than a potent wave as ASCAT from a few days ago concluded that there was a closed low, and convection was exceedingly defined at the time of that ASCAT pass.
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Quoting Patrap:


Morning counsler..

Yeppars,..and now we watch the Climatological favored areas as we swing into the 2nd half o-June.


I'm sure what ever has a shot a forming will come as a surprise. Cuz most people are likely taking a break after running around so much with 92l.
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3048. IKE
Quoting Chicklit:
Ike, a last gasp?
92L's yin yang calling card for the 2010 season sure got everyone's attention.


Getting choked to death. Yeah, it got everyone's attention.

I thought it was headed to a TD yesterday morning about this time and then it lost convection.

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quite or Quiet? People mess up that word a whole lot.
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3046. Patrap
Quoting kmanislander:


Good morning Pat. I agree. Like I posted yesterday morning you don't throw climatology out the window just because you have a potent wave in the deep tropics early in the season.


Morning counselor..

Yeppars,..and now we watch the Climatological favored areas as we swing into the 2nd half o-June.
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Quoting ElConando:


Und das Governator runs California

But who runs the Senate?

um, big oil?
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I am no longer expecting 92L to develop into a tropical depression due to its proximity to a band of shear to the north of the system. 92L continues movement towards the northwest and could possibly dissipate over the next 72 hours and could possibly become a naked swirl in just 48 hours. I think there is a low chance, about 10%, of 92L becoming a tropical depression.

I do have to say that 90L was a tropical depression late Saturday night and all of Sunday as an ASCAT pass proved that there was a closed low and there was exceedingly well satellite presentation.

I expect 92L to become TD #1 in post season analysis.
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4 to 6 days out tutt should begin to lift as shown on the wrf shear model.But yeh 92l is rip=done.
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That shear at 50w isn't going anywere anytime soon. The location of that TUTT reminds me alot of conditions across the atl in 2007. Tropics look quite during the next 3-5 days.
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92L should begin ti turn WNW-W very soon

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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.