Disturbance 90L close to tropical depression strength; TD 2 may rise again

By: Dr. Jeff Masters , 2:02 PM GMT en Agosto 14, 2009

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A strong tropical wave (90L), with a large circulation and a moderate amount of heavy thunderstorm activity, is a few hundred miles southwest of the Cape Verdes Islands, off the coast of Africa. This morning's QuikSCAT pass shows that 90L has a large circulation, but this circulation is not yet well-formed, as it is elongated along an east-west axis. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are gradually becoming better organized, with some spiral banding evident on the south side of the storm. Satellite intensity estimates from NOAA already put 90L at tropical depression strength with 30 mph winds, but the storm does not yet have a well enough formed circulation to be classified as a depression. Water vapor imagery shows that since 90L is forming several hundred miles south of the dry air of the Saharan Air Layer (SAL), the storm should not be affected by dry air and dust as much as Tropical Depression Two was. However, there is some dry air from the SAL being sucked into the circulation of 90L, and this is retarding its development.

Wind shear is moderate, about 10 - 15 knots, but is forecast to fall to the low range, 5 - 10 knots, later today. Shear is then forecast to remain low for the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow 90L to develop into a tropical depression by Saturday, and potentially reach hurricane strength by Wednesday. Most of our reliable models strengthen 90L into a hurricane by Wednesday, when the storm is expected to be near the northern Lesser Antilles Islands. One important outlier is the ECMWF model, which has 90L passing to the north of the islands, and eventually recurving out to sea east of Bermuda. The ECMWF was by far the most reliable model for forecasting hurricane tracks last year. However, all of our models are pretty unreliable going out 5 days in advance for systems that have yet to reach tropical depression strength. Once 90L becomes a tropical depression and develops a well-formed circulation, the models will have a better handle on forecasting where it will go.


Figure 1. The remnants of Tropical Depression Two (left side of image) and tropical wave 90L (right side of image).

Tropical Depression Two may come back
Tropical Depression Two died yesterday, but may rise again. Satellite loops of the remnants of the storm show that heavy thunderstorms are again attempting a comeback near the axis of what is now a tropical wave. However, dry air continues to interfere with the development of the thunderstorm activity, and moderately high wind shear of 15 - 20 knots is also inhibiting the process. Wind shear over the remnants of TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next four days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C two days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to the north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that any re-development of the storm will be slow to occur. NHC has given the system a medium (30 - 50% chance) of becoming a tropical depression again by Sunday morning. Only one reliable model, the NOGAPS, is predicting regeneration of TD 2. The NOAA Hurricane Hunters are flying research missions into the remnants of TD 2 today and Saturday.

I'll have an update Saturday morning, or earlier, if significant developments occur.

Jeff Masters

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Quoting CycloneOz:


That won't stop it. It's coming in here anyway...just like every other one has done.

I know. Just not as excited to see it surrounded by the WU style sheet as everyone else is.
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Quoting weathersp:


Starts to set up a stand outside the NHC

GET YE TORCHES AND PITCHFORKS HERE!!
Maybe a town hall meeting!!!
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ROFLMAO Pat!!!!!
Member Since: Septiembre 25, 2007 Posts: 53 Comments: 8533
2981. 7544
Quoting HurricaneKyle:


I guess the NHCs used to pulling cruel sick jokes at us.. at least this year lol!


they are workingg on the cone now lol
Member Since: Mayo 6, 2007 Posts: 0 Comments: 6785
Its out on youtube!!

http://www.youtube.com/watch?v=Yu_moia-oVI
Member Since: Posts: Comments:
If a major hurricane strike pascagoula, MS, then the biggest ship builder in the nation will be crippled. Ingles Shipyard.
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Show of hands........how many people can still READ the F5 on the key? (I have a few keys that are blank from use :)) :)) )
Member Since: Septiembre 25, 2007 Posts: 53 Comments: 8533
2977. Patrap
Member Since: Julio 3, 2005 Posts: 423 Comments: 127873
You know if your so excited, you could get up and do something and when you come back it will be there, instead of breaking your F5 key, after all you may need that tomorrow.
Member Since: Agosto 2, 2007 Posts: 19 Comments: 19234
2975. viman
Quoting Weather456:


I thought 90L was the only threat but then reconsidered TD 2.


Tell me about it, I started to breathe a little sigh of relief but quickly had to swallow my tongue and hold my breath again. I could use the rain, has really been dry here, cisterns hurting, but really don't want the damaging winds and marine weather that accompany these things
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this place has become a mental institution
Member Since: Julio 14, 2009 Posts: 0 Comments: 3015
Quoting sammywammybamy:
F55555555555555555...

**Drinks Some Coke**

Caffine is Good

lmao
I am laughing my ass off.......
Member Since: Septiembre 2, 2007 Posts: 178 Comments: 20439
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Quoting Weather456:



lol woah!, I'm killin myself of laughter


I guess the NHCs used to pulling cruel sick jokes at us.. at least this year lol!
Member Since: Agosto 10, 2009 Posts: 3 Comments: 672
2968. IKE
Sammy...you awake....alive....paging Sammy....

Member Since: Junio 9, 2005 Posts: 23 Comments: 37858
everyone on here is NUTS...LOL
Member Since: Julio 11, 2008 Posts: 0 Comments: 0
ROFLMAO!!!!!!!
Quoting weathersp:
Wait how fast did we go through that last page?!?!?


10-15 minutes
Member Since: Julio 24, 2005 Posts: 407 Comments: 19076
236? What? AM???!!!! roflmao!!!
Member Since: Septiembre 25, 2007 Posts: 53 Comments: 8533
Quoting BajaALemt:
*sitting here laughing REALLY hard!!*
same here
Quoting sammywammybamy:
f5...f5...F5...F5.... I am so going to get carpal tunnel syndrom


f5.f5.F5.F5.f5.f5.F5.F5.f5.f5.F5.F5.f5.f5.F5.F5.

That's how fast you should be going! Go for it, Man!
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Nothing yet, lol lol....
Member Since: Julio 24, 2005 Posts: 407 Comments: 19076
Wait how fast did we go through that last page?!?!?
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*sitting here laughing REALLY hard!!*
Member Since: Septiembre 25, 2007 Posts: 53 Comments: 8533
I would laugh if they didn't put it out till 10:59 lol
Member Since: Agosto 2, 2007 Posts: 19 Comments: 19234
Quoting jipmg:
Oh my god this blog is blowing up in anticipation of this advisory!


Of a TD that may or may not exist.

Yes...its been a LONG off season.
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Quoting IKE:
Nothing on the NHC site....blood pressures are rising...finger and toe-nails are being bitten off.....
LMAO
Quoting sammywammybamy:
f5...f5...F5...F5.... I am so going to get carpal tunnel syndrom


Man...that's not fast enough. Come on!
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Quoting Weather456:
what if the NHC page says nothing by 11PM

We have a glass of milk and go to sleep...lol
and leave it up to the youngin's who have it all figured out to fight for hours about whether it's gonna be a cat2 or cat4 10 days from now(they already have landfall pinpointed).
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Quoting sammywammybamy:
Florida going to get Wet tommorow by a Tropical Wave





Like it has not already rained enough this summer.

Anyone for an adult beverage while we're waiting on the update?

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no one post the advisory, only Sammy, got it! lol
no tds at 11
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2949. jipmg
Oh my god this blog is blowing up in anticipation of this advisory!
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2948. IKE
Nothing on the NHC site....blood pressures are rising...finger and toe-nails are being bitten off.....
Member Since: Junio 9, 2005 Posts: 23 Comments: 37858
Quoting HurricaneKyle:
If the NHC doesn't call it, it will be one of the cruelest sickest jokes I've ever seen them pull lol.



lol woah!, I'm killin myself of laughter
Member Since: Julio 24, 2005 Posts: 407 Comments: 19076
I haven't gotten the email from NHC yet, so it will probably be a TD again. I usually receive it by 10:35 and 4:40 am and pm.
Member Since: Agosto 27, 2006 Posts: 0 Comments: 1753
Quoting BajaALemt:
Wouldn't it be funny if Avila was reading the blog and saying, "Hey guys, lets not post it 'till 11:20' .....hehehhe
ROFLMAO!!!!!!!!!

im not waiting any longer.... going to bed since we all know we are not going to have any new td's until 5am.
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Quoting sammywammybamy:
Florida going to get Wet tommorow by a Tropical Wave



Yeap! Pcola is celebrating its 450 year aniversary. It should be a wash in the afternoon! Any one need a shower?
Sammy YOU CAN DO IT!!
Member Since: Julio 11, 2008 Posts: 0 Comments: 0
Quoting Weather456:
what if the NHC page says nothing by 11PM


Starts to set up a stand outside the NHC

GET YE TORCHES AND PITCHFORKS HERE!!
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Sammy is it there yet......come on man.....ROFLMAO
Member Since: Septiembre 2, 2007 Posts: 178 Comments: 20439
2937. RevInFL
Please no one commit stormaside. I am a trained counselor but my plate is full. LOL
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If the NHC doesn't call it, it will be one of the cruelest sickest jokes I've ever seen them pull lol.
Member Since: Agosto 10, 2009 Posts: 3 Comments: 672
Quoting Stormchaser2007:
Sammy focus here...

The lives of a few suicidal blogger hang in the balance.
ROFLMAO
Wouldn't it be funny if Avila was reading the blog and saying, "Hey guys, lets not post it 'till 11:20' .....hehehhe
Member Since: Septiembre 25, 2007 Posts: 53 Comments: 8533

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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.

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