High wind shear ripping into 97L

By: Dr. Jeff Masters , 1:49 PM GMT on July 20, 2009

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A strong tropical wave (97L) a few hundred miles east of Barbados in the Lesser Antilles Islands has grown less organized today as it tracks west at 15 - 20 mph. The wave is moving underneath an upper-level trough of low pressure, which is bringing 30 knots of wind shear to 97L. While there is a respectable amount of heavy thunderstorm activity associated with 97L, there is no longer any low-level spiral banding or rotation of the cloud pattern. This morning's QuikSCAT pass at 5:35 am EDT showed sustained winds of 35 mph a few hundred miles east of Barbados, but there was no surface circulation evident. The islands of Barbados, St. Vincent and the Grenadines, St. Lucia, and Martinique can expect heavy rain and wind gusts to 50 mph as 97L moves through the Lesser Antilles Islands this afternoon and tonight, but 97L will not become a tropical depression.

Wind shear along the path of 97L is forecast to remain in the high 25 - 35 knot range for at least the next three days. This should prevent further development of 97L, and I expect the disturbance will be gradually torn apart during the next few days. The National Hurricane Center gives 97L a low (less than 30% chance) of developing into a tropical depression in the next 48 hours. None of the computer models are forecasting any tropical storm development over the next seven days.


Figure 1. Current satellite image of African wave 97L.

I'll have an update Tuesday morning. As 97L moves through the islands, you may want to follow local observations there using our wundermap for the region.

Jeff Masters

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Quoting Twisterman555:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the button and ignored.

97L will do what it wants to do. Everyone has there own opinion, and people shouldn't be attacking people for what they say. People we will just watch this storm and see what it does. It has held up this long, it could be gone soon or stay together.


I repeat what has been said before,

Can we just ignore the noob and start actually debating Tropical Wave Ralphy (97L)

[NB: Ralphy is a name we gave it a few nights ago]
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Quoting southfla:
Below is the MIA NWS discussion this afternoon - this is partially why I believe that 97L is not the only player here in what the models are picking up off the east coast.

The latest short range models are showing that a upper level low will develop in the through of low pressure over the eastern Gulf of Mexico...and drift northeast across central Florida Tuesday through Wednesday night. At the same time...the northern portion of the tropical wave over the central Bahama Islands will move northwest and through South Florida Tuesday night. Another tropical wave over the windward and leeward island will also move northwest and through South Florida Wednesday night. This will keep the southerly wind flow over the County Warning Area...and allow for deep tropical moisture to work into South Florida from the Caribbean Sea during the next 48 hours. Rainfall amounts from these tropical waves will be discuss in the hydrology section below.

Extended forecast...
the upper level low will then move northeast away from South Florida late this week into this weekend. This will allow for high pressure to build back into South Florida from the Atlantic waters this weekend...and allow for the steering flow to swing from the southerly direction late this week to a southeast direction this weekend.


What I think is going to happen is the development that is shown in the Bahamas is from the interaction of 97L, the current wave in the Bahamas and the frontal boundary
nothing. forget it
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1060. sky1989
97L just refuses to die. I'm sure that many of us (myself included) are surprised that the tropical wave has done as much as it has given that it has never truly experienced any very favorable environment. Let's wait and see what is left of it tommorow, when it undergoes a much worse environment than it has ever experienced thus far...
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hello everyone whats the latest, i see some troll is on the blog anyone got the quicscat on this 97l
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Quoting BurnedAfterPosting:


Diurnal Min phase has just about started, sun will be going down in about 2 hours


No, Diurnal minimum is at its peak. Convection usually starts increasing after 10PM
Member Since: July 19, 2008 Posts: 43 Comments: 4051
97 is really hanging in there. Yet another burst of convection forming.
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1056. 7544
Quoting reedzone:
Convection refiring near DMIN... I think this INVEST will actually do something. It's firing off convection while getting heavily sheared (20-30 knots). It's an impressive INVEST.


plus 1
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Below is the MIA NWS discussion this afternoon - this is partially why I believe that 97L is not the only player here in what the models are picking up off the east coast.

The latest short range models are showing that a upper level low will develop in the through of low pressure over the eastern Gulf of Mexico...and drift northeast across central Florida Tuesday through Wednesday night. At the same time...the northern portion of the tropical wave over the central Bahama Islands will move northwest and through South Florida Tuesday night. Another tropical wave over the windward and leeward island will also move northwest and through South Florida Wednesday night. This will keep the southerly wind flow over the County Warning Area...and allow for deep tropical moisture to work into South Florida from the Caribbean Sea during the next 48 hours. Rainfall amounts from these tropical waves will be discuss in the hydrology section below.

Extended forecast...
the upper level low will then move northeast away from South Florida late this week into this weekend. This will allow for high pressure to build back into South Florida from the Atlantic waters this weekend...and allow for the steering flow to swing from the southerly direction late this week to a southeast direction this weekend.
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1053. KEEPEROFTHEGATE (Mod)
producing and displaying NHC material thats been alter to look like an official forecast is a copyright infringment and may face severe prosecution by federal auth.

you should refrain from such activity in light of the current active 2009 hurricane season official TWO's are issued by NHC
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The winds at the 3pm out of Hewanorra were NNE @ 8. The 4pm shows W @ 10. Currently out of the SE @ 20 in Barbados

International Weather Conditions
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Quoting Acemmett90:
Agreed and everyone this is the last post about JasonisaFATLOSER09
Everyone email the admin and tell him that he needs a perminate ban
how do u email the admin
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Quoting Stormchaser2007:


Ah that makes more sense. Just wasnt specific enough.


Diurnal Min phase has just about started, sun will be going down in about 2 hours
Convection refiring near DMIN... I think this INVEST will actually do something. It's firing off convection while getting heavily sheared (20-30 knots). It's an impressive INVEST.
Member Since: July 1, 2008 Posts: 13 Comments: 7436
Quoting SomeRandomTexan:
its almost 8 pm where 97l is... thats what he meant..


Ah that makes more sense. Just wasnt specific enough.
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Quoting Seastep:


Yep. Needs to stay S, though.


Yes, the further south it stays, the less shear it would have to experience
Member Since: July 19, 2008 Posts: 43 Comments: 4051
1039. Don't sink to his level, I think quite a few of us flagged it to the admin, and they will take the appropriate action. Calling him names does nothing except get you flagged and ignored.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
1044. 7544
97l is just about to wake up again good burst now begining stay tuned to part 5
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1042. Seastep
Quoting futuremet:
The development of a genuine LLC is helping it maintain its convection without relying on diurnal phases. This is a major change from yesterday.


Yep. Needs to stay S, though.
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DON'T FEED THE TROLLS!

This public service message was brought to you by jeffs713.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
its almost 8 pm where 97l is... thats what he meant..
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The development of a genuine LLC is helping it maintain its convection without relying on diurnal phases. This is a major change from yesterday....contrary to what most were expecting (naked swirls).
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Large intense convective burst with 97L. Some signs of life left in it. Doubt it'll do much though.
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1034. Patrap
Best to ignore the fray,..never quote one,..and just move along.

"The Best advice, is simple advice".

Retired Astronaut,now NASA administrator,Former U.S. Marine Bolden said that once.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
1033. KEEPEROFTHEGATE (Mod)
116

WHXX01 KWBC 201838

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1838 UTC MON JUL 20 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL972009) 20090720 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090720 1800 090721 0600 090721 1800 090722 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 13.4N 59.6W 14.5N 63.9W 16.4N 68.0W 18.0N 71.9W

BAMD 13.4N 59.6W 13.7N 61.8W 14.2N 64.4W 15.0N 67.4W

BAMM 13.4N 59.6W 14.1N 62.7W 15.2N 66.0W 16.5N 69.3W

LBAR 13.4N 59.6W 14.0N 62.8W 15.1N 66.3W 16.3N 70.0W

SHIP 25KTS 27KTS 31KTS 33KTS

DSHP 25KTS 27KTS 31KTS 33KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090722 1800 090723 1800 090724 1800 090725 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 20.0N 75.6W 23.8N 80.0W 26.8N 80.0W 29.4N 76.9W

BAMD 15.8N 70.6W 17.2N 77.1W 17.4N 82.6W 16.9N 87.6W

BAMM 17.9N 72.7W 20.6N 78.3W 22.5N 81.0W 24.2N 82.3W

LBAR 18.1N 73.7W 21.5N 78.4W 30.5N 77.5W 37.1N 68.6W

SHIP 36KTS 41KTS 48KTS 57KTS

DSHP 36KTS 39KTS 32KTS 37KTS



...INITIAL CONDITIONS...

LATCUR = 13.4N LONCUR = 59.6W DIRCUR = 280DEG SPDCUR = 19KT

LATM12 = 12.8N LONM12 = 55.7W DIRM12 = 280DEG SPDM12 = 18KT

LATM24 = 12.3N LONM24 = 52.2W

WNDCUR = 25KT RMAXWD = 40NM WNDM12 = 25KT

CENPRS = 1010MB OUTPRS = 1012MB OUTRAD = 120NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
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Quoting Acemmett90:

you a loser and your only doing this for attiontion


your right and everyone is giving it..
Member Since: July 17, 2008 Posts: 0 Comments: 385
Quoting BurnedAfterPosting:


actually it would probably be better cuz there would be no debate as to whether it was developing or not lol
. then they would be arguing over what catagories it will become, where it would be going, etc. there is always be arguing in here. it is the nature of the beast.
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Quoting Acemmett90:
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO! just die allready

Wish they would send a recon
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Let's get past this and back to business. Things will be taken care of. Also, see #999, I hope it helps. Now do what you do best.
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Quoting Stormchaser2007:


8pm is 4 hours away. Not that close in my books...lol


LOL yea I had to look at my clock really quick
Okay, let us stop talking about jasonisuncoolman09. He is laughing hard right now seeing us bickering about him...
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Quoting Vortex95:
8pm is almost here wonder how much convection will be left by then.


8pm is 4 hours away. Not that close in my books...lol
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Quoting TampaSpin:
Ban him but, he could be correct in 5 days.....LOL


Sad but true ...lol
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1021. KEEPEROFTHEGATE (Mod)


as of 4 pm edt
convective refire detected
nw of barbados
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Ban him but, he could be correct in 5 days.....LOL
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1017. scCane
Looks to me 97 is starting to pull a 2006 tropical storm Chris.
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I am sorry to day,but u jason are a troll it no life.U belong in the sewer.
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Someone who likes to make fake TWO maps obviously has no life.
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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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