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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917. Orcasystems
10:54 PM GMT on August 26, 2009

AOI

AOI

AOI

AOI

Member Since: October 1, 2007 Posts: 81 Comments: 26511
916. klaatuborada
10:10 PM GMT on August 26, 2009
trough does look like it's flattening, but there's a high pressure system to the West of Danny right now. Is it going to scoot over his north and then steer him up East coast? Depending on speed, I think the High pressure could loop him away. What am I not seeing?
Member Since: August 15, 2004 Posts: 23 Comments: 392
915. Cavin Rawlins
9:19 PM GMT on August 26, 2009


Member Since: July 24, 2005 Posts: 407 Comments: 19076
914. K8eCane
7:37 PM GMT on August 26, 2009
Quoting K8eCane:


i know what ya mean...been thru a few myself
i'm not exactly doing great in the recession so i dont have money to spare for extra plywood or expensive items and my point is i dont think i will need all that for this storm


but on second thought anybody reading this that isnt familiar with the drill, its not a bad idea to go ahead
better safe than sorry
Member Since: April 26, 2006 Posts: 5 Comments: 3138
913. extreme236
7:37 PM GMT on August 26, 2009
Quoting StormSurgeon:
Danny is in trouble! Low level circulation is distended f4om the absolute LOW. No Low, No breeze.


Give Danny time. Its not going to look good for a little while.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
912. K8eCane
7:34 PM GMT on August 26, 2009
Quoting cajunmoma:


having been through several hurricanes, may I offer advice...Get your supplies now, if you wait until the panic starts there will be nothing left. It is no fun when there is no gas, water, canned foods, plywood if you need it, generators, etc. Just a suggestion.


i know what ya mean...been thru a few myself
i'm not exactly doing great in the recession so i dont have money to spare for extra plywood or expensive items and my point is i dont think i will need all that for this storm
Member Since: April 26, 2006 Posts: 5 Comments: 3138
911. StormSurgeon
7:32 PM GMT on August 26, 2009
Danny is in trouble! Low level circulation is distended f4om the absolute LOW. No Low, No breeze.
Member Since: September 1, 2007 Posts: 0 Comments: 1793
910. justalurker
7:30 PM GMT on August 26, 2009
Quoting tropicfreak:


Where do you live.


sfla.
Member Since: August 18, 2009 Posts: 0 Comments: 157
909. cajunmoma
7:30 PM GMT on August 26, 2009
Quoting K8eCane:
i,m not buying any extra supplies until i hear of a warning...NOT a watch


having been through several hurricanes, may I offer advice...Get your supplies now, if you wait until the panic starts there will be nothing left. It is no fun when there is no gas, water, canned foods, plywood if you need it, generators, etc. Just a suggestion.
908. WxLogic
7:30 PM GMT on August 26, 2009
Quoting AllStar17:
I am predicting an orange circle for the AOI (soon to be 93L) off the coast of Africa at 8 pm. Looking good. Be back in a few.


Correctin... 94L. We already had 93L... :)
Member Since: August 14, 2008 Posts: 4 Comments: 4972
907. AllStar17
7:29 PM GMT on August 26, 2009
I am predicting an orange circle for the AOI (soon to be 93L) off the coast of Africa at 8 pm. Looking good. Be back in a few.
Member Since: June 29, 2009 Posts: 13 Comments: 5313
906. mikatnight
7:29 PM GMT on August 26, 2009
new blog!
Member Since: October 18, 2005 Posts: 4 Comments: 3052
905. hahaguy
7:28 PM GMT on August 26, 2009
The wave off Africa is looking good.
Member Since: August 12, 2007 Posts: 2 Comments: 2838
903. tropicfreak
7:27 PM GMT on August 26, 2009
Quoting justalurker:
you guys are scaring me..i think its time for me to drive up to NC..


Where do you live.
Member Since: September 2, 2006 Posts: 110 Comments: 6877
902. AllStar17
7:27 PM GMT on August 26, 2009
Quoting extreme236:
Once the ULL gets out of the picture we should see a better looking system. I agree it looks rather ugly right now.


Yep. I'll have a complete graphics and blog update later on Danny, Hilda, and Ignacio. Be back in a few minutes.
Member Since: June 29, 2009 Posts: 13 Comments: 5313
901. tropicfreak
7:26 PM GMT on August 26, 2009
Danny



Wave off Africa

Member Since: September 2, 2006 Posts: 110 Comments: 6877
900. justalurker
7:26 PM GMT on August 26, 2009
you guys are scaring me..i think its time for me to drive up to NC..
Member Since: August 18, 2009 Posts: 0 Comments: 157
898. mikatnight
7:26 PM GMT on August 26, 2009
Quoting earthlydragonfly:


I believe the is the upper level low seperating from Danny
Quoting jeffs713:

Warm water - yes.
Upper Atmospheric support - kinda. Its lower shear, but a bunch of dry air to mix out pumped into Danny by the ULL.


So is the ULL and Danny moving away from each other?
Member Since: October 18, 2005 Posts: 4 Comments: 3052
897. stormsurge39
7:25 PM GMT on August 26, 2009
Quoting tanman63:
I'm still having a hard time trusting the models on this one...Danny isn't overly vertical, especially on his west and south sides. Isn't it logical to assume his westward (or nearly westward) movement for atleast 24-36 hours until more convection builds and is steered more northerly?
good point
896. Browardjon
7:25 PM GMT on August 26, 2009
nothing like waiting til the last minute for supplies. isnt that when everythng is sold out?
Member Since: August 18, 2009 Posts: 0 Comments: 27
895. AllStar17
7:25 PM GMT on August 26, 2009
It may look ugly now, but it is still in the formative stages.
Member Since: June 29, 2009 Posts: 13 Comments: 5313
894. nrtiwlnvragn
7:25 PM GMT on August 26, 2009
Quoting hurricane23:


Uglyiest tc ive seen in a while...Both GFDL/HWRF bring a pretty significant cane up there.


SHIPS forward speed at the end is near 30 kt, thats a 1/3 of the wind speed there.
Member Since: September 23, 2005 Posts: 14 Comments: 11165
893. iluvjess
7:25 PM GMT on August 26, 2009
Models should move left.
892. extreme236
7:24 PM GMT on August 26, 2009
Not only does the CPC show increased cyclogenesis chances in the EATL this week, but also next week:

Member Since: August 2, 2007 Posts: 19 Comments: 19234
891. iluvjess
7:23 PM GMT on August 26, 2009
"i,m not buying any extra supplies until i hear of a warning...NOT a watch"

Guess you enjoy long lines... lol
890. StormSurgeon
7:23 PM GMT on August 26, 2009
Danny is totally distended from the T-Storm activity. Shear?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
889. extreme236
7:23 PM GMT on August 26, 2009
Once the ULL gets out of the picture we should see a better looking system. I agree it looks rather ugly right now.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
888. StormChaser81
7:23 PM GMT on August 26, 2009
Quoting StSimonsIslandGAGuy:
Actually it is uncommon off NE Florida and SE Georgia, StormChaser81. We do get nocturnal buildups of storms offshore, but in mid afternoon it is quite unusual.


Well I've seen it before, so blah.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
887. jeffs713
7:22 PM GMT on August 26, 2009
Quoting StormSurgeon:
The shear over Danny is weak. His ability to grow is dependent upon warm water and upper atmospheric support. Are those available?

Warm water - yes.
Upper Atmospheric support - kinda. Its lower shear, but a bunch of dry air to mix out pumped into Danny by the ULL.
Member Since: August 3, 2008 Posts: 16 Comments: 5881
886. tropicfreak
7:22 PM GMT on August 26, 2009
Quoting obsessedwweather:
StormSurgeon

What do you mean by a trough flattening? What does this mean now? Not recurving northward as some anticipated? Thank you.


Probably yes. When the trough flattened, it now extends west to east instead of SW to NE. That spells more trouble than thought for NC and VA coastline.
Member Since: September 2, 2006 Posts: 110 Comments: 6877
885. FLGatorCaneNut
7:22 PM GMT on August 26, 2009
Quoting K8eCane:
i,m not buying any extra supplies until i hear of a warning...NOT a watch


Shouldn't you have all your supplies prior to the start of Hurricane Season ??
Member Since: July 26, 2009 Posts: 0 Comments: 182
884. largeeyes
7:22 PM GMT on August 26, 2009
That is one ugly lookin storm. Hard to believe it won't disipate in 24 hours, let alone strengthen.
Member Since: August 22, 2006 Posts: 0 Comments: 1455
883. SeVaSurfer
7:22 PM GMT on August 26, 2009
Quoting Chicklit:

YIKES
Member Since: August 30, 2006 Posts: 0 Comments: 104
882. Engine2
7:20 PM GMT on August 26, 2009
I'm anxious to see a few more model runs and check the consistency of the current cone and ensembles
Member Since: February 27, 2006 Posts: 0 Comments: 482
881. obsessedwweather
7:20 PM GMT on August 26, 2009
StormSurgeon

What do you mean by a trough flattening? What does this mean now? Not recurving northward as some anticipated? Thank you.
Member Since: August 25, 2006 Posts: 0 Comments: 321
880. StormSurgeon
7:19 PM GMT on August 26, 2009
The shear over Danny is weak. His ability to grow is dependent upon warm water and upper atmospheric support. Are those available?
Member Since: September 1, 2007 Posts: 0 Comments: 1793
879. CaneWarning
7:19 PM GMT on August 26, 2009
Quoting StSimonsIslandGAGuy:
Hey Canewarning, about to head to our pool--how are you?


Sitting here at work and looking at the tropics! How's the weather there? They say we'll see heavy rain here but right now its sunny.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
878. tanman63
7:18 PM GMT on August 26, 2009
Talk about weird/unrealistic...HWRF has Danny down to a pressure of 945 mb 72 hours down the road....riiiiiight.
877. K8eCane
7:18 PM GMT on August 26, 2009
i,m not buying any extra supplies until i hear of a warning...NOT a watch
Member Since: April 26, 2006 Posts: 5 Comments: 3138
876. Buhdog
7:18 PM GMT on August 26, 2009
osuwxguy

Excellent post.

Member Since: July 30, 2005 Posts: 1 Comments: 960
875. Chicklit
7:18 PM GMT on August 26, 2009
Loop
Member Since: July 11, 2006 Posts: 14 Comments: 11328
874. palmbaywhoo
7:19 PM GMT on August 26, 2009
much closer to florida then it was yesterday
Member Since: August 18, 2008 Posts: 0 Comments: 393
873. JupiterFL
7:17 PM GMT on August 26, 2009
Quoting StormSurgeon:
Oh my, the trough up north flattened.
Good luck East Coast.

Sat Image


I think this goes hand in hand with what Seminolefan was talking about in post 782.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
872. VAbeachhurricanes
7:16 PM GMT on August 26, 2009



western side popping storms, trying to get more organized... alright well im off to buy supplies. peace
Member Since: September 6, 2007 Posts: 0 Comments: 6494
871. mikatnight
7:16 PM GMT on August 26, 2009
Quoting Chicklit:


That is quite the blob coming off Africa...I couldn't help but being a bit amused at Dr. Masters comments, "I am going to stop mentioning these forecasts until we get two models predicting the same thing, several model runs in a row." Sensing a tad of exasperation there...
Member Since: October 18, 2005 Posts: 4 Comments: 3052
870. hurricane23
7:14 PM GMT on August 26, 2009
Quoting nrtiwlnvragn:
Danny 18Z SHIPS indicates significant shear after 48 hours.


Uglyiest tc ive seen in a while...Both GFDL/HWRF bring a pretty significant cane up there.
Member Since: May 14, 2006 Posts: 8 Comments: 13787
868. WxLogic
7:13 PM GMT on August 26, 2009
Quoting Autistic2:
Will NE Florida catch any rain from Danny? We could use a little.


Not directly from Danny... but the pressure gradient should bring some showers onshore.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
867. wunderkidcayman
7:13 PM GMT on August 26, 2009
Quoting Chicklit:

looking better and better
Member Since: June 13, 2009 Posts: 2 Comments: 12024

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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.