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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274. bwat
Quoting OSUWXGUY:


I'm going to respectfully disagree...

There is a long arc of clouds feeding into the convection from the southwest into the convection and arcing off to the northwest out of the northern part of the convection.

The low level circulation as a whole looks better/more round than it has been in quite a while...if not its entire life.

RGB Loop


I was thinking the same thing but did not want to be accused of wishcasting, but yes the circulation looks better know than when they hd it at 60mph.
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However, the strong SSW flow associated with upper level low is starting to push off the coast. You can see this kicking off some convection in the far western portions of Danny's circulation.

There is only another 6-12 hour window for convection to fire over the CoC, unless the CoC starts moving to the north rapidly. Models still call for this...should be interesting to watch.
Quoting OSUWXGUY:


I'm going to respectfully disagree...

There is a long arc of clouds feeding into the convection from the southwest into the convection and arcing off to the northwest out of the northern part of the convection.

The low level circulation as a whole looks better/more round than it has been in quite a while...if not its entire life.

RGB Loop


I'm looking at the increased image number visual loop and the low level clouds to the east of the exposed center. They appear to be pulled eastward. We should know within an hour or two, recon is approaching the system.
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Member Since: September 14, 2007 Posts: 3 Comments: 3963
Quoting Weather456:



It is still to early to tell but due its southern most proximity and the fact that 90 Bill was almost to TD status at 30-35W, we can cancel out a Bill track for now.

How close it gets to the islands is uncertain but 20N (Ike) is becoming less likely.

So you are left with Luis.


I am watching and cannot come to any sure conlcusion at the moment.


I was going with a Bill track earlier though.
Hey there Weather, asked a question earlier. It looke like the low above 94L is moving out & 94L looks like it went a little more South. What is the feature that is to turn it more NW in a few days. I do not see it. Any ideas?
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Member Since: September 14, 2007 Posts: 3 Comments: 3963
dang...everything stopped for a few...what up...smoke break and no one told me??? lol
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Quoting Grothar:


I know we should keep on topic, but since we have a tiny lull in weather right now...
Sorry, I do not understand the reference to the shower curtain. I know it was mentioned the other night about Jim Cantore. Quite often these comments elude me. If it is something you shouldn't mention I'd rather you send it privately. We have ladies and youngsters here.


Since there is a lull in the WX...

Jim Cantore did a live shot last year in a hotel bathroom... nothing dirty about it. One of our young users was so inspired by the shot his avatar is strikingly similar to the shot Cantore used, so now we tease him about the shower curtain in his avatar.

That's it... just a little wunderground humor. ;-)

Here is a screenshot from the Cantore broadcast:

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Quoting nrtiwlnvragn:
I am thinking recon will find a LLC under the eastern convection ~29N 73-74W


I'm going to respectfully disagree...

There is a long arc of clouds feeding into the convection from the southwest into the convection and arcing off to the northwest out of the northern part of the convection.

The low level circulation as a whole looks better/more round than it has been in quite a while...if not its entire life.

RGB Loop
not watching the new waves yet...waiting for danny to do his thing...oldest son moving from DC to Charleston, SC this weekend...
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Quoting Grothar:


Classic!!!


I've seen that before in joke form. It says if you get up in the morning walk out the door and see this then, go back to bed.
Stormchaser...would love for you to send that one to my email...wanna forward it to a few people...roflmao
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Quoting StormChaser81:


This is one pissed off cloud, lol.


Classic!!!
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Quoting jasoniscoolman10:
i see a new wave about 20 west and 12 north wow..

Fred? maybe?
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258. JRRP
Link
Member Since: August 16, 2007 Posts: 0 Comments: 6154
Quoting tiggeriffic:
personally I think the main reason we have hurricanes is that it lets God show just how powerful he can be when he wants to be...makes us open up our eyes


You bet!!
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Hefalumps and WOOZLES!!!!!
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244. well, the certainly do transfer a LOT of energy....huge heat exchangers!
Member Since: September 14, 2007 Posts: 3 Comments: 3963
i see a new wave about 20 west and 12 north wow..
If they keep shifting the supposed centre of Danny West.. he is going to run aground on the North end of the Carols. (just for Press)

Blog Update
Reflector site for those at work, which includes Weather456, daily update.


AOI

AOI

AOI

AOI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
247. that's photoshopped! has to be!
Member Since: September 14, 2007 Posts: 3 Comments: 3963
personally I think the main reason we have hurricanes is that it lets God show just how powerful he can be when he wants to be...makes us open up our eyes
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hey tig...

y'all are an amusing bunch today ; )
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Quoting serialteg:


watch the road!



Looks like it!
I figured Tigger would get the reference for sure.
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243. yes, it's all your fault!
Member Since: September 14, 2007 Posts: 3 Comments: 3963
Quoting BobinTampa:


the hat AND the shower curtain.


I know we should keep on topic, but since we have a tiny lull in weather right now...
Sorry, I do not understand the reference to the shower curtain. I know it was mentioned the other night about Jim Cantore. Quite often these comments elude me. If it is something you shouldn't mention I'd rather you send it privately. We have ladies and youngsters here.
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240. serialteg 4:56 PM GMT on August 28, 2009
Quoting tiggeriffic:
LOL...my little one and myself look for things in the clouds while driving...keeps him occupied :D


I have auto pilot...i'm a mommy...lol
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Quoting pearlandaggie:
this will be a problem for any recurving storms......


And that is the main reason why nature creates Hurricanes. To transfer heat from the over heated seas to the poles. I cools down the waters.
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I see I sent everyone off on an animal in clouds tangent.
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YUM!!!! Spaghetti! LOL
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Quoting tiggeriffic:
LOL...my little one and myself look for things in the clouds while driving...keeps him occupied :D


watch the road!

Quoting KEHCharleston:
204. serialteg
: )
Heffalumps perhaps?


Looks like it!
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239. JRRP
94L???
Link
Member Since: August 16, 2007 Posts: 0 Comments: 6154
Bill went with tonns of sand here, literally. Another storm result in an unrecognisable coastline.
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BTW...afternoon press....
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like the probability of lightning striking twice in the same place, hurricanes rarely have the same path due to conditions never being exactly the same at 2 different times... have seen many canes look like they would follow a similar path and nail the same place one did years past...
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Quoting divdog:
Ok maybe the forecast is wrong so whatttt????


Well, the problem comes down to credibility. Cry wolf too many times, people don't listen anymore. Keep getting it wrong and people really don't listen anymore. I understand that mets aren't paid to be right, they are paid to guess. It's ok that you don't care, but the repercussions of this could be greater than you think.
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this will be a problem for any recurving storms......
Member Since: September 14, 2007 Posts: 3 Comments: 3963
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?



It is still to early to tell but due its southern most proximity and the fact that 90 Bill was almost to TD status at 30-35W, we can cancel out a Bill track for now.

How close it gets to the islands is uncertain but 20N (Ike) is becoming less likely.

So you are left with Luis.


I am watching and cannot come to any sure conlcusion at the moment.


I was going with a Bill track earlier though.
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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?


Hey Relix, It looks like the low above 94L is currently moving out. Could this what is causing the slight southward motion or are my eyes playing tricks. It seems much further south than before
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I am thinking recon will find a LLC under the eastern convection ~29N 73-74W
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it apparently rained some overnight here. i don't think it was too much rain, but as dry as things have been any rain is appreciated!
Member Since: September 14, 2007 Posts: 3 Comments: 3963
speaking of JFV...how did everything work out with the baby and all...good I hope...
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When are the hurricane hunters going back out into danny?
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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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