Danny weakens further; 94L worth watching

By: Dr. Jeff Masters , 1:54 PM GMT on August 28, 2009

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Tropical Storm Danny continues to weaken, and may merely be a tropical depression. Data from the Hurricane Hunters early this morning showed top winds of just 40 mph at the surface, and satellite intensity estimates of Danny's strength are now rating the storm a tropical depression. Danny looks very disorganized on satellite imagery (Figure 1), with the low-level circulation center exposed to view. There is no heavy thunderstorm activity near Danny's center, and only a small area of heavy thunderstorms lying several hundred miles east of the center.


Figure 1. Morning satellite image of Danny, showing the exposed swirl of clouds where Danny's center is, well displaced from the heaviest thunderstorm activity to the east.

The forecast for Danny
With wind shear at 15 knots this morning, and forecast to increase to 20 knots tonight and 30 knots Saturday morning, is is unlikely Danny will be able to strengthen to more than a 50 mph tropical storm. Dry air from the upper-level low that has been keeping Danny disorganized continues to be a problem for the storm, as well. The GFDL and HWRF models continue to insist Danny will strengthen to a strong tropical storm or weak Category 1 hurricane, but this seems very unrealistic given Danny's current struggles. With Danny's heavy thunderstorms all on the east side of the storm, it is unlikely that New England will feel tropical storm force winds from Danny when it scoots past on Saturday. Large swells from Danny creating high surf along the beaches of New England will be the primary hazard from the storm.

Massachusetts hurricane history
Two tropical storms have affected Massachusetts in the past decade, though neither of these storms brought sustained winds of tropical storm force (39 mph) to the state. Tropical Storm Beryl of 2006 just missed Cape Cod as a weak tropical storm with 45 mph winds. Beryl brought wind gusts to tropical storm force to Nantucket Island, and a 1 foot storm surge. Tropical Storm Hermine hit southeast Massachusetts on August 31, 2004, as a minimum-strength tropical storm with 40 mph winds. No land stations in Massachusetts reported tropical storm force winds during Beryl. The last time Massachusetts measured tropical storm force winds was in 1991 during Hurricane Bob, which hit Rhode Island as a Category 2 hurricane. Provincetown, Massachusetts measured sustained winds of 98 mph, gusting to 115 mph, and Buzzard's Bay received a 15 foot storm surge.


Figure 2. Tropical wave 94L, a few hundred miles west of the Cape Verdes Islands.

Invest 94L
A well-organized tropical wave (94L) lies a few hundred miles west-southwest of the Cape Verdes Islands. This disturbance has shown little change this morning. This morning's QuikSCAT pass shows a complete circulation, elongated in the east-west direction, with top winds of 30 mph. Satellite imagery shows only a small amount of heavy thunderstorm activity near the circulation center, but considerable thunderstorm activity south of the center. Shear is low, about 10 knots, and is expected to remain low to moderate, 5 - 15 knots, over the next five days. The waters are warm enough to support development, 28°C, and are expected to remain in the 27 - 28°C range over the next five days. The dry Saharan Air Layer (SAL) lies about 200 miles to the north and west of 94L, and it appears from water vapor satellite imagery that a modest amount of dry air from the SAL is now being ingested into the storm, slowing development. Dry air will continue to slow development until 94L's heavy thunderstorm activity can moisten the atmosphere enough to shield the storm from the Saharan Air Layer. NHC is giving 94L a medium (30 - 50% chance) of developing into a tropical depression by Sunday. The GFDL and SHIPS models both predict 94L will be a Category 1 hurricane five days from now. However, the HWRF model does not develop 94L. Most of the models predict 94L will take a significant northward jog 3 - 5 days from now, in response to a strong trough of low pressure passing to the north (this is the same trough of low pressure that will be recurving Danny out to sea). It is then probable that 94L will be forced to the west again as the high pressure ridge steering the storm builds back in, and 94L will likely be a few hundred miles northeast of the Northern Lesser Antilles Islands seven days from now.

I'll have an update this afternoon.

Jeff Masters

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Sorry for the delay in response. My computer or the blog or both is SLOW. Hello, Presslord. I've got the history channel 1938 storm program on in the background now. It's excellent. Hope you are well.
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12Z ECMWF dissipates 94L due to westerly shear.
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Quoting leftovers:
so chase you think 94 going to develop? nhc less than 50% still. i say near just before the windwards it might.


I say another 36 hours. It needs to consolidate convection over the center in order for it to develop. Once the easterly shear weakens then it should be able to do so.
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Quoting slavp:
SWLA Here...Very well said!!!

Indeed!
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469. slavp
Quoting nishinigami:


you guys are not alone, I live in Plaquemines parish. Gustav last year just about did the private levee behind my house in (thank goodness for those who did stay behind that sandbagged all day). I am extremely nervous about anything coming near us this year because of the Gulf temperature.

You are right though, we wait, watch, and hope for the best.

Thankfully we have this blog with so many people that can help us understand what is going on with the storms. A big thank you to all who contribute so much information to us :)
SWLA Here...Very well said!!!
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Quoting CaribbeanWave:
OKAY, 94L is still moving west! When is it going to make this northward turn? The longer this stays as an invest the more west it travels. if decides to turn to a TS when it gets near the caribbean then it would be very late to turn north.


It's moving lightly S of W...the westernmost part of the circulation appears to be at about 10.5N40.5W with a slight tendency to the south
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Quoting presslord:
History Channel is running a doc about the Great Hurricane of 1938...very interesting...

I've been reading "Isaac's Storm" about the 1900 Galveston Hurricane - great reading!
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Quoting Floodman:


Rats...I'll have to get energetic and look it up...

You're doing a great job by the way; the graphics and maps are good and very helpful, especially for those of us that don't have the time to dig out all of this data!


EUMETSAT
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Sorry Acorna, I was obviously only trying to help. Sounded to me like you didn't know how to use a search engine. When you come into a blog and ask for a link to information that is so easy to find it leads one to believe that you do not know how to utilize a search engine. I thought that would be valuable info.
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Quoting cajunmoma:


I am with ya! It is just a wait and see game now.


you guys are not alone, I live in Plaquemines parish. Gustav last year just about did the private levee behind my house in (thank goodness for those who did stay behind that sandbagged all day). I am extremely nervous about anything coming near us this year because of the Gulf temperature.

You are right though, we wait, watch, and hope for the best.

Thankfully we have this blog with so many people that can help us understand what is going on with the storms. A big thank you to all who contribute so much information to us :)
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I know this has been answered a million times, but how often do the models on this site get updated?

I know the model runs aren't as fequent before it a storm is a hurricane, but I can never remember when to check back.

BTW, does this site have an FAQ?
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Looking at the satelitte it appears that Danny's interaction with the front has allowed it western edge to improve....regardless of its affect on the track...what are the chances the front helps moisten Danny's center which is currently starved due to dry air??
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Quoting presslord:
History Channel is running a doc about the Great Hurricane of 1938...very interesting...


I was just reading an article on that "The Long Island Express.

1938 Slorm
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Quoting Stormchaser2007:
If the center of 94L is at 34W then its even more poorly organized than I thought. I wouldnt expect any kind of development for another 36-48 hours.



18Z initial conditions

LATCUR = 11.0N LONCUR = 36.0W DIRCUR = 280DEG SPDCUR = 19KT
LATM12 = 10.5N LONM12 = 32.0W DIRM12 = 276DEG SPDM12 = 19KT
LATM24 = 10.2N LONM24 = 28.8W
WNDCUR = 25KT RMAXWD = 75NM WNDM12 = 25KT
CENPRS = 1010MB OUTPRS = 1013MB OUTRAD = 200NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
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For lack of a better term, looks like bands from Danny are moving in here.

Link
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OKAY, 94L is still moving west! When is it going to make this northward turn? The longer this stays as an invest the more west it travels. if decides to turn to a TS when it gets near the caribbean then it would be very late to turn north.
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Quoting cajunmoma:


I am with ya! It is just a wait and see game now.

Lafayette here. I'm with you girls - it has been quiet. 94L is definately one to watch.
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Quoting AllStar17:


StormChaser --- The center is not at 34 W it is farther to the west.


I know that now its not at 34 W.

Regardless...
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Quoting nrtiwlnvragn:


This site allows you to select which models to plot.


That's the one that I had had, thanks so much :)

Also of note, trolls are best left ignored ;)
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452. bcn
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My two cents worth:

Don't believe this 11N - 36W/34W CoC..

There is a definite elongated rotation at 10N between 37-39W..

Anyone agree with me on this!?
Afternoon. Looks like Danny has put the brakes on as he considers what to do. Certainly has been an interesting sorta-tropical system. Computer models seem in a bit more agreement on 94L.
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Quoting Stormchaser2007:


They use the area next to the deep convection. lol


StormChaser --- The center is not at 34 W it is farther to the west.
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Quoting Orcasystems:


Really good.. long time no see by the way, I noticed you pop in but never for long. I have the link to load it into GE, but not a separate one?



Rats...I'll have to get energetic and look it up...

You're doing a great job by the way; the graphics and maps are good and very helpful, especially for those of us that don't have the time to dig out all of this data!
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Quoting Stormchaser2007:


Here you go.


Thank YOU
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The wave behind Possible invest 95L on the continent of Africa looks very impressive
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.
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Well,if Danny is going to make a move on us tomorrow,he better get moving.
Member Since: September 6, 2007 Posts: 881 Comments: 15833
Quoting Acorna:
Apologies for newbiness, but can someone post a link to the computer models? I remember last year there was a site (off of WU) that had a ton of models you could turn on/off, but I've lost the link :(


This site allows you to select which models to plot.
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Quoting bwat:
Link

Thanks!
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Quoting druseljic:


Or you could take advantage of this wonderful site which has many folks who don't mind answering a question like that. This is after all a weather blog and one of the best known for helping folks who have an interest in weather and are trying to learn!


right on my friend
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Afternoon Everyone! I've been lurking on the board for 3 years now and have learned alot. I never posted so I figured I would sign in and give it a try..Looks as if we will only have minimal affects from Danny here in eastern NC.
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Quoting iluvjess:
"Apologies for newbiness, but can someone post a link to the computer models? I remember last year there was a site (off of WU) that had a ton of models you could turn on/off, but I've lost the link :("

If you type "www.google.com" into your address bar, a sight will come up that is called a searh engine. In the box in the center of the page type "hurricane tracking models" and then click on the search button. The next page will bring you to a list of sites containing the search criteria. I am sure that you will find the models on one of these sites. In the future, you can use search engines like google to look for any information on the internet. Give it a try it's really easy.


Or you could take advantage of this wonderful site which has many folks who don't mind answering a question like that. This is after all a weather blog and one of the best known for helping folks who have an interest in weather and are trying to learn!
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Quoting iluvjess:
"Apologies for newbiness, but can someone post a link to the computer models? I remember last year there was a site (off of WU) that had a ton of models you could turn on/off, but I've lost the link :("

If you type "www.google.com" into your address bar, a site will come up that is called a searh engine. In the box in the center of the page type "hurricane tracking models" and then click on the search button. The next page will bring you to a list of sites containing the search criteria. I am sure that you will find the models on one of these sites. In the future, you can use search engines like google to look for any information on the internet. Give it a try it's really easy.


or you can continue to ask people on here, the majority of us don't mind answering questions, we are usually glad to help
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting Floodman:
Hey Orca, for whatever reason, my link to Eumet is not working...can you post it for me?

Thanks!

How you been, by the way?


Really good.. long time no see by the way, I noticed you pop in but never for long. I have the link to load it into GE, but not a separate one?

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Quoting CaribBoy:


I wonder where did they find these cooridates


They use the area next to the deep convection. lol
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Well local mets said absolutly no rain from danny and here in myrtle beach we have gotten almost an inch just in the afternoon all coming off the ocean
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If the center of 94L is at 34W then its even more poorly organized than I thought. I wouldnt expect any kind of development for another 36-48 hours.

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432. bwat
Quoting presslord:
History Channel is running a doc about the Great Hurricane of 1938...very interesting...
Thanks, I caught the very end of this a while back, have not seen this part.
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Quoting midgulfmom:

Hello, LA Mom here too. It does seem rather quiet in the GOM. I'm grateful and anxious now with 94L and the next possible invest behind it with all of the talk of a high building and heading some of these storms westward.:p


I am with ya! It is just a wait and see game now.
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Quoting texascoastres:
stormpulse is showing 94l at 9.4N 39.6W


I wonder where did they find these cooridates
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Quoting cdnbananabelt:


Is that African dust I see in the western Caribbean?


Its just regular dust that shows up sometimes.
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Question is, Will Danny still be in Bahama's when 94L gets there?
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Quoting btwntx08:

36w at 12z


Now they have changed that to 34W in the best track files. They must have done further analysis and concluded the position at 12Z was 34W.
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just to clear up the argument, 94L position at 18Z is 11n - 36W, it was 10.5N - 36W 6 hours ago.. so either the center relocated or there is an error somewhere...
"Apologies for newbiness, but can someone post a link to the computer models? I remember last year there was a site (off of WU) that had a ton of models you could turn on/off, but I've lost the link :("

If you type "www.google.com" into your address bar, a site will come up that is called a searh engine. In the box in the center of the page type "hurricane tracking models" and then click on the search button. The next page will bring you to a list of sites containing the search criteria. I am sure that you will find the models on one of these sites. In the future, you can use search engines like google to look for any information on the internet. Give it a try it's really easy.
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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.