Tropical Storm Danny likely to be named today

By: Dr. Jeff Masters , 1:25 PM GMT on August 26, 2009

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First-light satellite images of the tropical wave (92L) a few hundred miles northeast of the Bahama Islands show that the system has developed an organized surface circulation, and 92L will likely be named Tropical Storm Danny later today. This morning's QuikSCAT pass confirms the presence of a surface circulation, and the satellite saw top winds of 50 mph in a cluster of thunderstorms well east of the center. Wind shear has dropped to the moderate range, 10 - 15 knots. The upper-level low 92L is moving underneath has plenty of dry air in it, and the upper low is injecting this dry air into 92L's west side, keeping and heavy thunderstorm activity from developing on that side. The Hurricane Hunters are in 92L, and have found surface winds up to 57 mph so far this morning. NHC continues to give 92L a high (greater than 50% chance) of developing into a tropical depression by Thursday afternoon.


Figure 1. Water vapor satellite image from 8:15 am EDT 8/26/09 showing dry air associated with an upper-level low pressure system to the west of 92L's center of circulation. Image credit: NOAA/SSD.

The forecast for 92L
As 92L continues to plow through the upper low, the low will weaken, and wind shear is expected to decline to the low range, 5 - 10 knots, by tonight. However, the upper-level low will continue to dump dry, cold air into 92L through Thursday afternoon, slowing down development. By Thursday night, when 92L should be several hundred miles off the coast of northern Florida, the upper-level low may be weak enough and far enough away that 92L will find itself in a region with light upper level anticyclonic winds, which would favor more rapid development. Most of the intensity models, including the GFDL, HWRF, and SHIPS model, forecast that 92L will become a hurricane by Friday. However, this favorable environment will not last long, since a strong trough of low pressure will be approaching the U.S. East Coast on Friday. This trough will bring high wind shear of 20 - 30 knots by Friday night. This trough should be strong enough to turn 92L to the north. The models have come into better agreement keeping 92L offshore as it passes North Carolina, though the storm is certainly capable of giving the Outer Banks a direct hit. As 92L passes North Carolina, it should start heading north-northeast, with a second landfall likely Saturday night or Sunday morning somewhere between Massachusetts and Nova Scotia. At that time, 92L is likely to be a strong tropical storm or weak Category 1 hurricane, with winds in the 55 - 80 mph range. It currently appears that 92L will not bring tropical storm-force winds to the Bahamas or to Florida.

Elsewhere in the Atlantic
The models have been inconsistently predicting formation of several tropical waves coming off the coast of Africa over the next week, and I am going to stop mentioning these forecasts until we get two models predicting the same thing, several model runs in a row.

I'll have an update later today.

Jeff Masters

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466. bingcrosby
4:37 PM GMT on August 26, 2009
F-storms are any storms that knock a tree down in my yard.
Member Since: August 14, 2008 Posts: 0 Comments: 137
465. 789
4:36 PM GMT on August 26, 2009
Quoting JLPR:
so everyone is ignoring the tropical wave south of the CV islands O_O



its looking very good and no comments about it? xD
see what dr. m says at top of page there coming just not today
Member Since: July 18, 2009 Posts: 0 Comments: 262
464. NEwxguy
4:35 PM GMT on August 26, 2009
Thanks Storm,nice analysis,will be watching this closely
Member Since: September 6, 2007 Posts: 878 Comments: 15739
462. scott1968
4:34 PM GMT on August 26, 2009
Hi, can anyone answer this question? During the last El Nino season how many land falling hurricanes(CONUS)were there compared to fish storms? I know, I know every season is different just curious.
460. wunderkidcayman
4:34 PM GMT on August 26, 2009
Quoting Acemmett90:

and then we will have the dreaded f storm

LOL what is with you and F-storms
Member Since: June 13, 2009 Posts: 2 Comments: 12038
459. WxLogic
4:34 PM GMT on August 26, 2009
Quoting JLPR:
so everyone is ignoring the tropical wave south of the CV islands O_O



its looking very good and no comments about it? xD


12Z GFS is bringing that system to the Carib in 120HR or so... or by Monday.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
458. BiloxiIsle
4:33 PM GMT on August 26, 2009
Let's keep the Gulf off limits for the rest of the season!
Member Since: May 11, 2008 Posts: 0 Comments: 153
457. HopquickSteve
4:33 PM GMT on August 26, 2009
Morning! So 93L became danny and not 92? With all of these storms so close to each other... How much does someone want to bet that someone starts ranting about the "Fujiwhara Effect" as all of the storms follow the omniscient "XTRP"?

Link
Member Since: May 17, 2006 Posts: 0 Comments: 635
455. JLPR
4:33 PM GMT on August 26, 2009
Quoting Acemmett90:

and then we will have the dreaded f storm


and who knows =P
maybe the f storms max out at 40mph and goes to sea lol
Member Since: September 4, 2007 Posts: 36 Comments: 5223
454. jeffs713
4:32 PM GMT on August 26, 2009
Quoting JLPR:
so everyone is ignoring the tropical wave south of the CV islands O_O



its looking very good and no comments about it? xD

Since TS Danny could impact people in the next 5 days, it is by far the focus right now. The CV wave might get some attention in a few days, once Danny moves out. Keep in mind anything by the Cape Verde Islands is easily a week away, if not more.
Member Since: August 3, 2008 Posts: 16 Comments: 5882
453. Alockwr21
4:30 PM GMT on August 26, 2009
Quoting StormW:


Thank you!


Good stuff Storm! I too think the models should go a little more left now that they have a COC to work with.
Member Since: September 12, 2007 Posts: 0 Comments: 725
452. Bordonaro
4:30 PM GMT on August 26, 2009
Quoting hurricanehanna:
I know I am untrained, but I just don't see how this was named yet. The moisture is all on the west side.

The atmospheric dynamics per the NHC and Quiksat Satellite show that TS Danny has a low level closed circulation, along with winds of 45MPH in the NE quadrant. I believe the Florida Tropical research group also agreed that the make-up of the storm is tropical in nature. The upper level low that's cutting off the convection in the NW quadrant is forecasted to move away and allow for intensification. Look at the Water Vapor Satellite imagery from the NHC to get a better view of the TS and the pesky upper level trough.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Was my question so dumb that no response was deemed necessary? Oh well, back to lurking. I can pick up a bit just by reading the blog.
Member Since: August 23, 2009 Posts: 0 Comments: 16
449. IKE
Quoting DestinJeff:


hey Ike .... greetings from Southside 285. that GFS seems odd, the Low seems to appear/disappear thru the cycle


Hello, from the NW side of 285.

Has it go east of NC/SC and make landfall in New England.

Looks like most of the convection stays on the east side of Danny on the GFS.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Hurricane Bob and Danny are cousins!

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445. JLPR
Quoting btwntx08:

i was wondering the same thing it could become a invest before everyone notices it


yep I believe we might have one soon if the wave keeps developing convection
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting JLPR:
so everyone is ignoring the tropical wave south of the CV islands O_O



its looking very good and no comments about it? xD

well we could have 94L soon maybe TD6 maybe even TS ERIKA
Member Since: June 13, 2009 Posts: 2 Comments: 12038
441. JLPR
Quoting obsessedwweather:
JLPR

Brought it up earlier, but I rarely get a response. Definitely something to watch.


thank you for replying
I usually get ignored too when i talk about it =\
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting StormW:
Good afternoon!

I have a new synopsis posted.

Thanks!

TROPICAL WEATHER SYNOPSIS /DANNY/ AUG. 26, 2009 ISSUED 12:20 P.M. EDT

Great Update Storm - Thanks! :)
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439. IKE
GOM is off limits right now w/up to 50 knots of shear.....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting StormW:
Good afternoon!

I have a new synopsis posted.

Thanks!

TROPICAL WEATHER SYNOPSIS /DANNY/ AUG. 26, 2009 ISSUED 12:20 P.M. EDT


thanks storm.checking out now.
Member Since: August 18, 2009 Posts: 0 Comments: 157
Quoting hurricanehanna:
I know I am untrained, but I just don't see how this was named yet. The moisture is all on the west side.
all the convection is on the eastern noreastern side with swirl west of it got named because of its closness to land and a poss quick spin up later tonight after 11 pm till dawn and also the fact that this after noon it will be 48 hrs and normally after the first 48 you can get a good convective cycle going tonight but as always we wait and see the AOI off cv islands has a high chance nice arc in the se quadand wrapping
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JLPR

Brought it up earlier, but I rarely get a response. Definitely something to watch.
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Boy, Bastardi's right on the money this year :P
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432. IKE
12Z GFS......has Danny making landfall near Cape Cod,MA.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting hurricanehanna:
I know I am untrained, but I just don't see how this was named yet. The moisture is all on the west side.


All the convection is on the east side.
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Quoting KEEPEROFTHEGATE:


so hows lunch 42 mins left eat and type fast


ROTFLMAO!!
Member Since: August 18, 2009 Posts: 0 Comments: 157
The COC is ahead of all of the moisture. You can see it better through the visible satellite.

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NAM puts it right smack outside my front door Fri-Sat. Hmmm... note - self - start yard pick up tomorrow when back at the beach. Hope old Danny boy hears the pipes further east...
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Quoting DestinJeff:
Nice visible loop of Danny here.... getting his swirl on

Link


thanks for the link..great look close up
Member Since: August 18, 2009 Posts: 0 Comments: 157
oooh, boy, another one coming close by my Old Cape Cod.

Well, school starts in two weeks, most people are leaving, although we've got the gruesomes hanging around since Mr. K. died last night. I wonder if Mr. O will cut his vacation short and leave prior to weekend.

Here's hoping it's just a tropical storm when it comes by for a visit. I'm tired of people who are more concerned whether tourists show up rather than the welfare of all. Oh well. I guess I'm just depressed now that I'm unemployed. Stuff happens. As do storms.

We're having beautiful weather right now. Looks like it's going to be nice for 3 whole days in a row! I hope we're not going to pay too high a price for that, but that seems to be the way of it. The micro climate here is definately in a Ying Yang pattern!
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420. JLPR
so everyone is ignoring the tropical wave south of the CV islands O_O



its looking very good and no comments about it? xD
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting eddye:
it looks like dannycould head to south east fl and the bahamas


so hows lunch 42 mins left eat and type fast
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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.