Southeast U.S. development

By: Dr. Jeff Masters , 6:25 PM GMT on July 17, 2006

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The tail end of an old cold front over the waters off the Southeast U.S. coast could serve as the focus for some tropical development over the next few days. Some impressive thunderstorms are developing over the waters due east of Georgia, thanks to a narrow area of reduced wind shear of 5-10 knots that has developed here. The GFS computer model is indicating that this reduced shear will remain for the next few days, and the Hurricane Center has scheduled a reconnaissance aircraft to check the system out on Tuesday at 2pm EDT, if needed. The system is over the warm Gulf Stream waters, where sea surface temperatures are very favorable for development, 28-30 C. The system is still pretty disorganized, although the latest visible imagery is hinting at a surface circulation. I believe that the earliest a tropical depression would form is Wednesday.

Steering currents are weak, so it is difficult to tell where this system might go. A strong trough of low pressure is expected to push off the East Coast by Wednesday, so this may turn the disturbance northwards and recurve it out to sea. However, it's quite possible the trough will not be strong enough to grab the disturbance, which will wander about off the Carolina coast for most of the week.


Figure 1. Latest satellite image of the Southeast Coast disturbance.


Figure 2. Preliminary forecast model tracks for the SOutheast Coast disturbance.

A very large area of concentrated thunderstorms is a few hundred miles northeast of Puerto Rico. This is associated with a tropical wave interacting with an upper-level low pressure system. Wind shear is 20 - 30 knots over this area, and no tropical development is expected. We will have to watch this area later in the week as it approaches the East Coast, but it appears now that wind shear will remain too high to allow development.

An extratropical or subtropical low is about 220 miles south-southeast of southwestern Nova Scotia, and is moving northeast away from the U.S. at 20 mph. The storm is over the Gulf Stream where water temperatures are in the upper 70s, which is borderline for a tropical storm. The low has a large area of heavy thunderstorms on the northeast side of the center of circulation, and is undergoing significant wind shear that is exposing the center. This storm is not a threat to develop into a tropical storm, since the waters in front of it are too cool to allow tropical development.

>
Figure 3. Visible satellite image for 8am EDT July 17 2006, showing the various areas of interest along the East Coast.

A solid-looking tropical wave has just emerged off the coast of Africa, and is headed towards the Cape Verde Islands at 15-20 mph. Water temperatures are marginal for tropical development in this region, wind shear is high, 10-30 knots. I'm not expecting this wave to be a threat, even though the wind shear forecast shows wind shear dropping tomorrow. It's very common this time of year to see impressive looking waves come off the coast of Africa, only to fizzle after spending a day over the water. If the wave is still holding togther by this time tomorrow, I'll take it seriously. But I think we need another two weeks for the waters to warm before these African waves will bear watching.

Jeff Masters

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652. ricderr
1:45 PM GMT on July 18, 2006
C2NEWS

Are you one of those reporters that gets a woody over a storm?...out there reporting like you've got danger in the palm of your hand? I'm career Navy. I've seen ugly things all my life. They bring me no pleaure. Three years ago my wife and I purchased what will be our retirement home on the Indian River of Jensen Beach, FL. We've been through 3 hurricanes in the last 2 years. Calling for a complete rebuild of our home, outbuilding, dock and the complete loss of our sailboat that my wife and I spent 4 years refurbishing it to it's origins of 1926. To watch storms...to try to predict them....understand them and be awestruck by them I have no problem and i include myself in this category. To want them to hit land makes me sick.
Member Since: June 27, 2006 Posts: 676 Comments: 22351
651. thelmores
1:29 PM GMT on July 18, 2006
seems to me, that some tstorms are trying to form very near the center of our carolina storm ("frick")..... we will have to see if this persists....

this is definitaly a sign of possible intensification.........
Member Since: September 8, 2005 Posts: 0 Comments: 3805
650. C2News
1:22 PM GMT on July 18, 2006
yeah i know i noticed that about frances....it tok jax through a five day ride....even though jeanne had the brunt in jax overnight.....in the morning we woke up to all the roads within 3 blocks of the ocean flooded
Member Since: July 17, 2006 Posts: 73 Comments: 622
649. PBG00
1:20 PM GMT on July 18, 2006
Oh..just wondering..Went through Francis and Jeanne too...Even though Francis was weaker it was worse cause it just sat over us for hours and hours
Member Since: October 20, 2005 Posts: 14 Comments: 6650
648. Cavin Rawlins
1:20 PM GMT on July 18, 2006
dr. jeff has a new blog.....
Member Since: July 24, 2005 Posts: 407 Comments: 19076
647. WSI
1:19 PM GMT on July 18, 2006
New blog!
646. C2News
1:19 PM GMT on July 18, 2006
I was anywhere from jacksonville to palm bay....i live in jax
Member Since: July 17, 2006 Posts: 73 Comments: 622
645. C2News
1:18 PM GMT on July 18, 2006
yeah a cat 3 is okay i've gone through it before (Jeanne 04) though I wasn't as prepared as I hadn't restocked my hurricane kit from Frances.....I rode out Frances in a makeshift hut in Palm Bay..till Melbourne police threw me out...i got great footage though
Member Since: July 17, 2006 Posts: 73 Comments: 622
644. PBG00
1:17 PM GMT on July 18, 2006
Where in Fla wre you?
Member Since: October 20, 2005 Posts: 14 Comments: 6650
643. thelmores
1:15 PM GMT on July 18, 2006
so c2, a cat 3 heading your way is ok???

LOL....glutton for pinishment! :)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
642. WSI
1:15 PM GMT on July 18, 2006
NAM as of this morning is showing more or less the same solution it was yesterday. A push into NC, then riding up the coast a little.
641. C2News
1:13 PM GMT on July 18, 2006
i'm the only floridian that thinks like that (excluding my news crew!)
Member Since: July 17, 2006 Posts: 73 Comments: 622
640. C2News
1:12 PM GMT on July 18, 2006
no i live in florida i want it to hit here (just as longf as its not a cat 4 or cat 5 hurricane i can stand anything else) I have been waiting since 2004 for nother hurricane to hit near me
Member Since: July 17, 2006 Posts: 73 Comments: 622
639. thelmores
1:11 PM GMT on July 18, 2006
"I do not see how this does anything but head NE, but that is just from looking at the WV loops. Maybe I am missing something."

i must be missing it too! LOL

Guess the HH should be on station around 3pm..... guess we'll "finally" get some answers! :)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
638. WSI
1:11 PM GMT on July 18, 2006
"I do not see how this does anything but head NE"

Well right now the steering currents are weak. Wouldn't take much of a push west from the BH to change everything.
637. Rolltide
1:09 PM GMT on July 18, 2006


CZ

Hopefully wrong on the NE drift?

where do ya live,Bermuda?
636. C2News
1:06 PM GMT on July 18, 2006
yeah seems to have a NE drift but hopefully i am wrong! ):
Member Since: July 17, 2006 Posts: 73 Comments: 622
635. C2News
1:04 PM GMT on July 18, 2006
some of my keys are sticking sorry
Member Since: July 17, 2006 Posts: 73 Comments: 622
634. StormJunkie
1:04 PM GMT on July 18, 2006
Morning all
thel, the gfdl was also run at 8, but because it is a much more complex model the data output for it along with the likes of the GFS, Nogaps, CMC, and Ukmet, will not be out until about 2. Just how long it takes teh models to eat all of there data.

I do not see how this does anything but head NE, but that is just from looking at the WV loops. Maybe I am missing something.

See ya'll later. Off to work
SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
633. C2News
1:04 PM GMT on July 18, 2006
i dunno when it comes out thelmores....i wonder wehn dr masters ill update his blog?
Member Since: July 17, 2006 Posts: 73 Comments: 622
632. thelmores
1:01 PM GMT on July 18, 2006
the BAMM, BAMD, LBAR, and A98E 8am runs all show a nw component at some point.....

hmmmm....

when is the next gfdl?
Member Since: September 8, 2005 Posts: 0 Comments: 3805
631. Cavin Rawlins
12:58 PM GMT on July 18, 2006

97L
Member Since: July 24, 2005 Posts: 407 Comments: 19076
630. C2News
12:58 PM GMT on July 18, 2006
oh shoot all the models have tracks shifted more northeast
Member Since: July 17, 2006 Posts: 73 Comments: 622
629. guygee
12:49 PM GMT on July 18, 2006
Posted By: GulfScotsman at 12:44 PM GMT on July 18, 2006.
ponder... hmmmm

ponder ponder ponder..... hmmmm


OK, Gulf, you've pondered long enough, now spit it out if you've got something to say...
Bye-bye on the by and by.
Member Since: September 16, 2005 Posts: 0 Comments: 3200
628. thelmores
12:47 PM GMT on July 18, 2006
would that ruin some stone tablets???? :D
Member Since: September 8, 2005 Posts: 0 Comments: 3805
627. thelmores
12:47 PM GMT on July 18, 2006
A TROPICAL DEPRESSION MAY BE FORMING.

no "sub" or "extra" rhere! LOL
Member Since: September 8, 2005 Posts: 0 Comments: 3805
626. pcolabob
12:45 PM GMT on July 18, 2006
The long range GFS has shown the eatl wave del. and move wnw and hit se fla and move into the GOM on its last 3 runs. I know this is a long way out and the long range models are not very accurate but if this trend in the model continues it will be somethihng to watch. with the sst in the gulf we dont want something already del. getting into the GOM.
Member Since: August 3, 2011 Posts: 0 Comments: 0
622. thelmores
12:43 PM GMT on July 18, 2006
good points getreal..... would seem that the ULL coming from the sse may be the end of our carolina storm...... especially if the caroilina continues eastward........

seems its biggest opportunity may be just to stay put, and i dont see that! :)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
619. guygee
12:41 PM GMT on July 18, 2006
thelmores - Remote possibility, but I see the base of the mid-level trough retrograding, and the ULL is still pushing towards the west...so I don't rule out some retrogression (drift towards the west)for 97L. The models say otherwise...

Catch you later, gotta go!
Member Since: September 16, 2005 Posts: 0 Comments: 3200
617. Cavin Rawlins
12:40 PM GMT on July 18, 2006
000
WONT41 KNHC 181221
DSAAT
SPECIAL TROPICAL DISTURBANCE STATEMENT
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
820 AM EDT TUE JUL 18 2006

SATELLITE AND SURFACE OBSERVATIONS THIS MORNING INDICATE THE LOW
PRESSURE AREA LOCATED ABOUT 250 MILES SOUTHEAST OF NORTH CAROLINA
COAST HAS BECOME BETTER ORGANIZED THIS MORNING... AND A TROPICAL
DEPRESSION MAY BE FORMING. AN AIR FORCE RESERVE RECONNAISSANCE
AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM THIS AFTERNOON.
INTERESTS ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SHOULD
CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM.

$$
FORECASTER STEWART
Member Since: July 24, 2005 Posts: 407 Comments: 19076
615. GetReal
12:34 PM GMT on July 18, 2006
Three wx factors going against 97L developing further this morning in my opinion:
1) Southwesterly wind shear.
2) EXTREMELY DRY CONTINENTAL AIR entraining into the system from the west.
3) Very dry air approaching the system from the east.
Member Since: July 4, 2005 Posts: 204 Comments: 8898
614. thelmores
12:33 PM GMT on July 18, 2006
dangit, knew i forgot to do something this morning! the martins! DOH!

guess it could be a power plant or something...... guess i'd have to try to determine a more "exact" location.....

as for the ULL affecting the carolina storm ("frick"), i dont think it will play a major role in track, but certainly could affect intensity.....

terograde back west? can you explain more what could cause this..... i just dont see it..... course havent had my coffee yet! LOL

Member Since: September 8, 2005 Posts: 0 Comments: 3805
613. guygee
12:32 PM GMT on July 18, 2006
Will do , WSI, I need to get on the road to Orlando today to work, but I am curious about the little purple beasties, so I will definitely check in when I get there. It is very interesting how they apparently take off nearly at the same time, ascending and scattering almost uniformly...I would like to learn more...

Talk to everyone later!
Member Since: September 16, 2005 Posts: 0 Comments: 3200
612. guygee
12:26 PM GMT on July 18, 2006
hurricane23 - Anyways, on the visible loops I agree, I see some low-level convergence bands NW of the main area of convection curling in cyclonically...
Member Since: September 16, 2005 Posts: 0 Comments: 3200
611. nash28
12:24 PM GMT on July 18, 2006
Good morning everyone. The EATL wave is looking fairly healthy. It appears as though the model consensus for 97l has it curving out to sea.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
610. EdMahmoud
12:23 PM GMT on July 18, 2006
I just checked the watervapor for 97L. It has very dry air to the West, which matched up very well to where the circulation has thunderstorms and where it doesn't. On the IR Channel 2, it almost looks like a sheared system, with half the circulation exposed, but I think that is all dry air.

OK- my dark horse system of the day: The showers and thunderstorms sinking into the Gulf off Louisiana and Texas this morning.


Shear between 10 and 20 knots, not super-favorable, but not too unfavorable.


Something for Gulf Scotsman to ponder.
Member Since: October 19, 2005 Posts: 0 Comments: 1150
609. WSI
12:23 PM GMT on July 18, 2006
No problem guygee.

If you get a chance, look at that Wiki article on the Purple Martins I linked on my forum. They only live in housing provided by humans. That is pretty interesting.
608. guygee
12:21 PM GMT on July 18, 2006
Sorry, make that "NW" ?
Member Since: September 16, 2005 Posts: 0 Comments: 3200
607. guygee
12:20 PM GMT on July 18, 2006
hurricane23 - Switched to visible, are you looking at the area NE of the convection?
Member Since: September 16, 2005 Posts: 0 Comments: 3200
606. hurricane23
12:17 PM GMT on July 18, 2006
Good morning just looking at first visibles and 97L looks a tad bit better organized then yesterday.recon will tell us more.

right now iam seeing a possible LLC elongated to the NW.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
605. Cavin Rawlins
12:15 PM GMT on July 18, 2006
Good Morning: 97L is holding out.....and EATL wave has not only hold together but got mentioned by the NHC..........
Member Since: July 24, 2005 Posts: 407 Comments: 19076
604. guygee
12:14 PM GMT on July 18, 2006
Will - Thanks for that explanation, it seems to make sense. Over the Everglade birds often show up during migratory season.
Member Since: September 16, 2005 Posts: 0 Comments: 3200
603. bappit
12:13 PM GMT on July 18, 2006
durn, should check my mail more often. That is pretty amazing.
Member Since: May 18, 2006 Posts: 10 Comments: 6157
602. guygee
12:12 PM GMT on July 18, 2006
bappit - Are there electrical power generation plants located at the centers of those "clutter bursts"? If true, that would seem to be more than just coincidence, if it happens at all three.
Member Since: September 16, 2005 Posts: 0 Comments: 3200

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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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