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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Member Since: September 6, 2007 Posts: 0 Comments: 6494
Quoting hurricanehanna:

Thanks! I missed being on here. I was Jonesin all day for an update and the NHC does not give me the fix I need! lol


Yeah, this blasted blog is addicting. I got on Patrap's bad side last week, admonishing him for callousness towards other bloggers. He then set me straight and made me feel about two feet tall…I didn’t show back up for 5 days, but couldn’t stay away. Word to the wise to any newbees: don’t mess with Pat - especially before he's had his coffee - he eats pinheads (like me) for breakfast. Hey Pat - you out there? And, have you eaten yet?
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Facebook fan page for Tropical Storm & Hurricanes. Would like to see some avid storm trackers add to the discussion and keep Facebook users up to date on what is happening in the tropics.
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Quoting Norfolker:
I will be watching this one carefully. Here in SE Virgina the ground is saturated from a very wet Aug. It will not take much wind to uprout trees here. I have 4 very tall pines in my yard. Lets wishcast this one away from the coast.


seriously... 7 inches of rain here in the past 2 weeks...
Member Since: September 6, 2007 Posts: 0 Comments: 6494
Quoting largeeyes:
ECU-
Well, hard to be caught off guard if we're aware its coming. Gives me an excuse to pick up the chainsaw I've been wanting to buy :)


You and I are aware of it. But I did a poll in the office and most individuals had no idea... My brother in Manteo didn't even know untill I mentioned it this morning.
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Member Since: September 6, 2007 Posts: 0 Comments: 6494
If the storm follows the gulf stream with low wind shear, It has the potential to become a cat 3 or 4 , so people from charleston s.c. to cape cod need to be prepared.
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I will be watching this one carefully. Here in SE Virgina the ground is saturated from a very wet Aug. It will not take much wind to uprout trees here. I have 4 very tall pines in my yard. Lets wishcast this one away from the coast.
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Quoting Alockwr21:
Washington, North Carolina Here. Right on the pamlico river.

It'll be interesting to see if these models move further west at all or stay about where they are now.

Since the center is a bit west of where the models were initiating it and its path is already suppose to be NW according to those same models, I assume they will continue to shift a little bit west
Member Since: February 27, 2006 Posts: 0 Comments: 482
Plenty of Oceanic Heat Content along the Gulf Stream if this thing hugs the coast south of North Carolina!

Just for reference, anything ~90 or above is supportive of rapid intensification. Fortunately, the upper air conditions don't appear like they'll be favorable enough for 92L to undergo RI.

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Washington, North Carolina Here. Right on the pamlico river.

It'll be interesting to see if these models move further west at all or stay about where they are now.
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Preliminary Extended Forecast Discussion

EAST COAST/TROPICS...
TROPICAL SYSTEM NEAR 24N 69W CONTS TO INTENSIFY. GLOBAL MODELS
CONT TO HAVE A MORE WESTERLY TRACK WHILE IT INTERACTS WITH A
LINGERING MID LEVEL TROF OVER ERN CONUS LATE THURSDAY AND EARLY
FRIDAY ALLOWING IT TO LIFT RAPIDLY NWD WHILE HURRICANE MODEL
GUIDANCE CONTS TO CLUSTER WITH A MORE OFSHORE TRACK. ALL PHASE
DIAGRAM GUIDANCE INDICATES A MDT/DEEP SYMETRIC WARM CORE LOW
BECOMING BAROCLINIC ONCE IT REACHES HIGHER LATITUDES. HAVE RE
ADJUSTED DAY 3 SAT TOWARDS A DEEPER AND JUST OFF SHORE VA CAPES
SOLUTION FOR NOW WITH AN ATTEMPT TO SHOW THIS TRANSFORMING TOWARD
A BAROCLINIC LOW WITH A CMC/ECMWF BLEND SOLUTION. LATEST NAM RUNS
CONVERGING ON A DEEPER TREND CLOSER TO CMC. LATEST NHC/TPC
OUTLOOKS INDICATE THAT THIS SYSTEM WILL BE A TROPICAL STORM AND
NAMED TODAY. SEE NHC/TPC OUTLOOKS AND FUTURE ADVISORIES/WARNINGS.
CURRENT PRELIMS ARE TOTAL HPC DEPICTION. UPDATED AFTN HPC FINALS
WILL REFLECT CO ORDINATED NHC/HPC POSITIONS FOR DAYS 3 AND 4.



Preliminary Graphics
Member Since: September 23, 2005 Posts: 14 Comments: 11163
Quoting 7544:
on visable looks like the naked swirl is moving due west and clouds expand further west as afr as 75 west needs to fill in and the tunes will change


Seems to be moving a little north of due west.
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My Forecast (what the heck, I'll give it a shot
and either get brownie points of constructive criticism :) ):
11am Wed 8/26: Tropical Storm Danny (~50 mph)
11am Thu 8/27: Tropical Storm near 150 miles east-northeast of the northern-most Bahama Islands(~65 mph)
11am Friday 8/28: Category 1 Hurricane about 300-400 miles southeast of Cape Fear, NC (~75 mph)
Around midnight Friday night (8/28-8/29): Closest approach to the Outer Banks of North Carolina as a category one hurricane (~85 mph)
11am Saturday 8/29: Category one hurricane 100-200 miles east of the DelMarVa (~80 mph)
11pm Saturday 8/29: Closest approach to southeastern New England (most likely between Fall River, MA, and 40 N/70 W, but could be as far west as western Long Island and as far east as 68-69 W) as a moderate to strong tropical storm (~65-70 mph)
11am Sunday 8/30: Near or over Nova Scotia as a moderate tropical storm, becoming extra-tropical (~45-60 mph)

Thoughts? Comments? Objections? Suggestions? Too many questions? LOL
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53. IKE
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52. 7544
on visable looks like the naked swirl is moving due west and clouds expand further west as afr as 75 west needs to fill in and the tunes will change

or maybe they will relocate the coc at 23/ 68 where the heavy conv is now
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I am off to work.. you guys have fun :)
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
50. IKE
COC is completely exposed. I doubt the NHC names it at this point.
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ECU-
Well, hard to be caught off guard if we're aware its coming. Gives me an excuse to pick up the chainsaw I've been wanting to buy :)
Member Since: August 22, 2006 Posts: 0 Comments: 1455
My guess is by 11am we'll have TS Danny, a track similar to Bill , maybe tracking a little closer to the east coast.
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Quoting mikatnight:


Well that's disturbing. No due process. Seems like you should have the right to meet your accuser (the pic). Anyway, welcome back.

Thanks! I missed being on here. I was Jonesin all day for an update and the NHC does not give me the fix I need! lol
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Quoting ncstorm:


Thanks..so why is the blog saying the storm will pass east of NC if we dont have the correct data yet?


Because that is what the models are saying. Hopefully the majority of the strong winds will stay on the east side when it brushes the NC Coast. I hope this one doesnt blow up too much and catch us in NC off gaurd.
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Appreciate it.
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Quoting hurricanehanna:

I have no clue...they didn't tell me.


Well that's disturbing. No due process. Seems like you should have the right to meet your accuser (the pic). Anyway, welcome back.
Member Since: October 18, 2005 Posts: 4 Comments: 3052
92L is too weak to be a tropical storm just yet. Hurricane hunters can't even find TS force winds now. Western side is non-existent and the ULL will continue dumping dry air into the system.

I don't see Danny....yet.
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42. 7544
sorry nothing is written in stone
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I have not even seen indications of 30kt winds yet,

Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting largeeyes:
Still wondering if the info from the NOAA HH flight will be in 12Z models....anyone?


Not sure for the NAM, but any data collected, especially dropsondes by 10 AM EDT should make it into the 12Z GFS run. You can check which data at this webpage.
Member Since: September 23, 2005 Posts: 14 Comments: 11163
92L/Danny
Lame system
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Quoting WxLogic:


Correct... models are currently initialized on a guess of where the LLC could potentially be...


Thanks..so why is the blog saying the storm will pass east of NC if we dont have the correct data yet?
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Looking forward to the 12z runs...advisories should certainly start at 11 am given the closed circulation and strong tropical storm force winds AND close proximity to the eastern seaboard, no? I'm curious to see the kind of track NHC puts up. The ECMWF still has the storm turning north-northwest at the end of the period, moving into New York City, but only as a weak tropical storm. NAM is scary and hopefully off but with the Gulf Stream nearby and shear expected to relax who really knows at this point...
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Wow - so the future Danny had TS winds but no center? Is that unusual? It sounds like a giant thunderstorm mass.
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Still wondering if the info from the NOAA HH flight will be in 12Z models....anyone?
Member Since: August 22, 2006 Posts: 0 Comments: 1455
Good Morning Everyone!

Another interesting day on tap...

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Quoting ncstorm:
In order for the track to be on point..wouldnt we have to have a define COC before saying the storm will stay off the coast..I thought the computer models werent reliable because of that? Am I wrong?


Correct... models are currently initialized on a guess of where the LLC could potentially be...
Member Since: August 14, 2008 Posts: 4 Comments: 4972
I think we all need a little excitement. Lets do a rain dance. ;-D
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Quoting ncstorm:
In order for the track to be on point..wouldnt we have to have a define COC before saying the storm will stay off the coast..I thought the computer models werent reliable because of that? Am I wrong?


Yes. Even the extrap is suspect. Now that there is a defined center to track, future runs will be more accurate.
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Good morning sir and thanks. I look forward to your updates.
When discussing "Surge" I wonder if there are any considerations given to what we, here on the Southern TX coast, have called a "slosh effect" in the estuaries and bays. A gradual rise due to tides, low pressure and waves is compounded by winds pushing the waters in front of the storm. When the storm passes the waters rush back to the opposite side of the bay. The result is a high reverse "Surge" on our barrier island. Is this an effect that we should be aware of?
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Quoting mikatnight:


What image were you accused of posting?

I have no clue...they didn't tell me.
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Quoting largeeyes:
I swear, if Danny knocks that tree on my house the week before the party, I am going to be seriously unhappy.


Can I drive my car up there and park it under it, lol.

Piece of S*&@ Murano.
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In order for the track to be on point..wouldnt we have to have a define COC before saying the storm will stay off the coast..I thought the computer models werent reliable because of that? Am I wrong?
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Quoting hurricanehanna:
whew! they let me back in! Morning all - I was banned for posting an image, but I have not been able to post images, so I don't understand the ban, but oh well. Nice to be back in. I was totally lost yesterday. 92L still looks to be an east coast storm, correct?


What image were you accused of posting?
Member Since: October 18, 2005 Posts: 4 Comments: 3052
post went poof into the blogosphere LOL



92's coc is well defined now. has an actual O marking the spot.

Not likeing the CMC run from sfwmd!!
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New Bern, NC. Not terribly far from Morehead City/Atlantic Beach and thus Cape Lookout and what not.
Member Since: August 22, 2006 Posts: 0 Comments: 1455
This is going to be nothing but a nuisance storm for anyone along the southeast coast, regardless of landfall. The western side of "Danny" is much weaker than the eastern side. Any kind of landfall will bring some gusty winds and a few bands of rain. This will be a strong Nor'easter at best, and thats if it can get close enough to the coast. I still think it remains well offshore and produces another weekend of rough surf for the eastern seaboard.
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yeah I would just in case Largeeyes because it seems the OBX will either get hit or brushed if anyone in the Southeast does.
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Quoting StormW:
Good morning!

Thanks Jeff!

What's happening this morning gang? Just got on and getting ready to do analysis


Not much... 92L has a better LLC now but no convection around it. ~24.5N70w. Still being affected by the TUTT to its SSW... and there's a HH doing a check on it at the moment.
Member Since: August 14, 2008 Posts: 4 Comments: 4972
Live in New Bern, NC which is close enough to the OBX for me to grab some gas for the generator just in case.
Member Since: August 22, 2006 Posts: 0 Comments: 1455
Largeeyes where are you located?
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whew! they let me back in! Morning all - I was banned for posting an image, but I have not been able to post images, so I don't understand the ban, but oh well. Nice to be back in. I was totally lost yesterday. 92L still looks to be an east coast storm, correct?
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Thanks Ike.
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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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