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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When are the hurricane hunters going back out into danny?
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no real clouds to look at here today...just gray and overcast...trying to rain...
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222. 789
Quoting AussieStorm:

cause there is not much going on atm in the tropics
see anything with the yucatan pinn going on
Member Since: July 18, 2009 Posts: 0 Comments: 262
I like the dove best...
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hey tig...glad you like them! :)
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Quoting FLdewey:


I just got this screen shot from the webcam in the NHC conference room. Which one is JFV?

JFV



Are those sitting on the floor the computer models? why they do not have their darts in their hands to shoot at the Atlantic map for the forecast? havent they realize we need an update on 94L? LOL just a bit of Humor NHC are the best in the business.
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204. serialteg
: )
Heffalumps perhaps?
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LOL...my little one and myself look for things in the clouds while driving...keeps him occupied :D
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Quoting Relix:
W456, concerning your update, I was looking at Ike's track:



Now, Ike was able to miss the islands because it was already quite a bit to the north. If 94L were to do something like this, wouldn't it keep a track similar to Luis's



Of course, I am just talking about the point until the Antilles, not the recurve part, that seems quite hard to happen right now. Would 94L follow a track similar to these storms, but probably closer to the islands considering how south it is and the through not that strong... plus the system still developing?


if you watch the steering movie i posted some posts back you'll see it can really keep west so it's a watcher
Member Since: August 22, 2006 Posts: 2 Comments: 1975
one more...check this one out....
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Rapid Scan of Danny's expose low level center

Its like Andrea with convection

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found this one on flikr.....
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Afternoon all...bouncin in for just a few...
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Quoting serialteg:




wow, that's crazy!
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208. Relix
W456, concerning your update, I was looking at Ike's track:



Now, Ike was able to miss the islands because it was already quite a bit to the north. If 94L were to do something like this, wouldn't it keep a track similar to Luis's



Of course, I am just talking about the point until the Antilles, not the recurve part, that seems quite hard to happen right now. Would 94L follow a track similar to these storms, but probably closer to the islands considering how south it is and the through not that strong... plus the system still developing?
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207. JRRP
GFS is showing E-F-G in this run
Link
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I can understand why Danny ended up much further west than expected but I'm surprise it did. The system is that shallow.
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Quoting AussieStorm:

cause there is not much going on atm in the tropics

Goodnight all
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Quoting pearlandaggie:


hahaha! talk about seeing things in the clouds!


Member Since: August 22, 2006 Posts: 2 Comments: 1975
Quoting IKE:


So Claudette didn't hit anyone? Or Bill?


Use ignore, he's a troll.
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Quoting largeeyes:
I'm very certain now. It's an elephant.


hahaha! talk about seeing things in the clouds!
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Quoting iluvjess:
Why is it soooooooo slooooooow in here?

cause there is not much going on atm in the tropics
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189. I agree. It looks like Dumbo!
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Quoting K8eCane:
afternoon everybody
who wants some sizzlin hot homemade crispy fried chicken
mashed potatoes and gravy hot buttermilk bicuits with sliced tomatoes and chocolate brownies extra fudgy with sweet homemade iced tea?

anyhow in all fairness to danny, it is right breezy here and it looks like he might be gettin ready to throw some showers our way
and just when you think its safe to go back in the water...duh duh duh duh...along comes 94L
Save some for me. Sounds like one of my favorite meals.
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Quoting klaatuborada:


Dude, it's already raining in New Bedford and soon Buzzards Bay. We're going to get it way before 8pm.
Ok maybe the forecast is wrong so whatttt????
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Quoting JLPR:
94L is looking a bit disorganized
but it has a good circulation


I see the big thunderstom and shower activity mostly east, as in maybe something not associated with the LLC (around 12N - 34W) and south, more into the ICTZ. Let's see how this plays out.



Quoting nolacane2009:
What do yall give the odds of 94L forming into a TD by Saturday and continuing a Westerly Track?


Steering for 1000mb 5 day movie no forecast
Member Since: August 22, 2006 Posts: 2 Comments: 1975
Thank you very much.
Member Since: August 19, 2009 Posts: 0 Comments: 248
Quoting nolacane2009:
What do yall give the odds of 94L forming into a TD by Saturday and continuing a Westerly Track?


Pretty good. All models have it at TS strength by 36 hours.

Member Since: September 9, 2008 Posts: 6 Comments: 3414
I'm very certain now. It's an elephant.







Member Since: August 22, 2006 Posts: 0 Comments: 1451
188. Relix
Quoting JLPR:
94L is looking a bit disorganized
but it has a good circulation

Not good. The weaker the more west it goes.
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187. bwat
Quoting nolacane2009:
What do yall give the odds of 94L forming into a TD by Saturday and continuing a Westerly Track?
Hard to say, if it was more of a threat to land right now it most likely already would be. I guess it just depends how long they want to watch it and see where the models go. Most of the public has no clue what a 94L is, and the NHC is going to want to have a good bead on an initial track before declaring it tropical. Just my opinion.
Member Since: August 18, 2009 Posts: 0 Comments: 353
186. JRRP
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Why is it soooooooo slooooooow in here?
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Quoting nishinigami:
Was there an 11 update model run for 94L? The link on the tropical tab still says 8am.

Thanks

Next one is at 2, they run at 8 & 2 both am & pm
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181. bwat
Quoting nishinigami:
Was there an 11 update model run for 94L? The link on the tropical tab still says 8am.

Thanks
Try this Link it usually updates before the models page here.
Member Since: August 18, 2009 Posts: 0 Comments: 353
SYNOPSIS
TROPICAL STORM DANNY WILL REMAIN WELL EAST OF THE
FLORIDA COASTAL WATERS AS IT RECURVES AND MOVES UP THE EASTERN
SEABOARD. SWELLS GENERATED BY DANNY WILL IMPACT THE LOCAL WATERS
INTO SATURDAY. REFER TO THE LATEST ADVISORIES FROM THE NATIONAL
HURRICANE CENTER CONCERNING DANNY. A LIGHT SOUTH TO SOUTHWEST WIND
FLOW WILL DEVELOP OVER THE WEEKEND AS THE ATLANTIC HIGH PRESSURE
RIDGE AXIS SHIFTS SOUTH OF THE AREA.

From NOAA-going to be a geat surf weekend, waxing the board now....
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What do yall give the odds of 94L forming into a TD by Saturday and continuing a Westerly Track?
Member Since: August 19, 2009 Posts: 0 Comments: 248
178. JLPR
94L is looking a bit disorganized
but it has a good circulation
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Is it me, or does Danny look like an elephant on Rainbow?
Member Since: August 22, 2006 Posts: 0 Comments: 1451
Quoting jeffs713:

The rain is having a hard time pentrating the CT/RI border. 8pm looks about right.


You see, the Cape has it's own Micro-Climate. You can't use Boston weather, nor can you use Providence RI weather. What happens out here 80-90% of the time is hardly ever forecast correctly. Last Tuesday morning it was raining here, and there was NO rain in any forecast anywhere. It did clear out, turned into a beautiful night, but...

For the big weather patterns most forecasts can be somewhat accurate for us, but for the everyday stuff, the small stuff, no one ever gets it right for the Cod. We're sticking out with the warm water south, the cold north, and depending on how things get bumped in either direction dictates what we actually get vs what is predicted.

I don't think it's splitting hairs when people plan to go outside and do things and it rains 7 1/2 hours earlier than anyone said. People rely on forecasts to help them plan their day.
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Was there an 11 update model run for 94L? The link on the tropical tab still says 8am.

Thanks
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174. bwat
Quoting hamla:
if danny boy gets to 30.3 and 76.0 and stops for 12 hrs that east blob could make things interesteng
just a thought
It may make it there, who knows, but that ULL aint gonna let him sit for 12 hours by no means.
Member Since: August 18, 2009 Posts: 0 Comments: 353

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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.