Tropical Depression Three forms

By: Dr. Jeff Masters , 3:42 PM GMT on July 22, 2010

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Tropical Depression Three has formed over the Bahama Islands, and appears poised to become Tropical Storm Bonnie later today. Satellite images of TD 3 show a modest area of heavy thunderstorms that have slowly increased in intensity and areal coverage this morning. The surface circulation center is exposed to view, thanks to strong upper-level winds out of the southwest that are creating about 20 knots of wind shear. This wind shear is due to the counter-clockwise circulation of air around a large upper-level low pressure system over Florida that is moving west at about the same speed TD 3 is. Water vapor satellite loops show a large area of dry air is associated with the upper-level low pressure system, and this dry air is hindering development of TD 3. The storm is attempting to wrap a curved band of clouds around its center, on its west side. If TD 3 is able to do this, the center will be protected from shear and dry air, and more significant strengthening can occur. Surface observations in the Bahamas and several nearby ships have shown top winds in TD 3 of up to 35 mph, so the storm is close to the 40 mph winds needed to be classified as a tropical storm.


Figure 1. Water vapor satellite image showing dry air (brown colors) associated with the upper-level low over Florida. Image credit: NOAA/NESDIS.

Track Forecast for TD 3
The storm is in a fairly straightforward steering current environment, and TD 3 should progress steadily to the west to west-northwest through Saturday. This will bring the storm ashore over the Florida Keys or South Florida on Friday, and into the Gulf of Mexico on Saturday. The latest set of model runs from 2am EDT (6Z) had the advantage of having data from a flight of the NOAA jet last night, so we have higher confidence than usual in the track of TD 3 over the next two days. The location of TD 3's final landfall along the Gulf of Mexico coast has the usual uncertainties for 3 - 4 days, with the various models calling for landfall somewhere between the upper Texas coast and the Florida Panhandle coast. Given the uncertainties, the move halt operations in the Deepwater Horizon blowout recovery effort are probably wise.

Intensity Forecast for TD 3
The primary detriment to development of TD 3 for the next three days will be the presence of the large upper-level low to its west. As long as this low remains in its present location, relative to TD 3, it will bring wind shear of about 20 knots and dry air into the storm. This will limit the intensification potential of TD 3 to no more than about 10 - 15 mph per day. If the upper-level low slow down a bit, relative to TD 3, more shear will affect the storm, potentially weakening it. Conversely, if the upper-level low picks up speed and pulls away from TD 3, the storm may be able to intensify at a faster rate. None of the computer models is calling for that to happen, but it would not take much of an additional separation between TD 3 and the upper level low to substantially reduce shear and allow TD 3 to intensify into a hurricane on Saturday. I put the odds of TD 3 making it to hurricane strength in the Gulf of Mexico at 20%.

98L
An area of disturbed weather (98L) has developed in the Gulf of Mexico's Bay of Campeche. This system is under a low amount of shear, 5 - 10 knots, and may barely have enough time to organize into a tropical depression before making landfall along the Mexican coast a few hundred miles south of the Texas border on Friday.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Next update
I'll have an update between 3 - 4 pm, when the Hurricane Hunters will be in the storm. I'll also speculate on the possible impact the storm will have on the oil spill region.

Jeff Masters

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1121. leo305
Quoting leo305:


Katrina had a similar path..

Moved NW/NNW over the bahamas, then the High over the south pushed in and forced it WNW/W towarsd SFL and then WSW..


In fact Katrina had a similar look to it back in 2005 when it was east of florida..

this has more water to cover though
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Cantore was in Galveston when Ike came ashore.
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Quoting Tazmanian:



ok

wtf
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Quoting jlp09550:


Yeah, I noticed the "logical" word right after I posted it, sorry! Maybe someone else can explain then.


Gulf is small... Sea medium and ocean big...
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Quoting MiamiHurricanes09:
There is no such thing as weak RI. Also, RI is a pressure drop of at least 42mbs.



ok
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1115. xcool
wnw i'm used VIS/IR2 Floater 2
Member Since: September 26, 2009 Posts: 2 Comments: 15603
1114. Grothar
Anyone think this will change a little at 5PM?

Member Since: July 17, 2009 Posts: 63 Comments: 23726
Are the storms along the SE Texas coast related to 98L or just the afternoon heating type?
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So with all model changes, does that mean it most likely will not hit the florida panhandle?
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If Recon misses the LLC again, Then please cue the "Benny Hill" music
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Quoting DestinDome:
Alot of the model guidance for 2 pm is now aiming back to the Northern Gom Louisiana



And the GFDL didnt kill it on this run.
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Quoting Tazmanian:


may be going under a weak RI
There is no such thing as weak RI. Also, RI is a pressure drop of at least 42mbs.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Well, I already did the fix on a run over Nassau.... about 20 - 24 hrs Due NW, and it would be a bullseye... lol

I like the low road better for Bonnie, with her Scottish self...

lol
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Quoting pensacolastorm:
If you want to be safe at landfall go whereever Cantore is. He can't buy a storm - they always land where that little dweebie guy goes.


If he has a real close shave on the old knoggin then he's ready for work.
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The Bahamas aren't in the Caribbean.
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Nice convection at the center.
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Quoting sarahjola:
what do you think its doing?:)


may be going under a weak RI
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all of the models have significantly shifted East. All call for a LA landfall....

Link
Member Since: September 25, 2007 Posts: 0 Comments: 207
Quoting jlp09550:


Yeah, I noticed the "logical" word right after I posted it, sorry! Maybe someone else can explain then.


Don't worry it was logical to assume that he meant definition
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Quoting Tazmanian:
1006.4 mb
(~ 29.72 inHg)


1006.4mbs found



i hop its not doing what i think its doing
what do you think its doing?:)
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1099. jscs
Quoting BahaHurican:
Typical FOX. The Bahamas is in the Atlantic Ocean and not on or in the Caribbean Sea...



You really should stop watching Faux News.
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Quoting BahaHurican:
Notice, BTW, that the HHrs have been able to fly their entire pattern down there without encountering land...



Thats good because planes should only encounter land, when landing.
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Maybe I need new contact lenses, but not looking as impressive as it did this morning. Sheer maybe??
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1095. Times2
Link

I think it's obvious that we are seeing a closed circulation and a wrap taking place.
Click on the enhancement feature and select GOES 12 water vapor color enhancement and ZOOM in.
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1094. leo305
Quoting Jeff9641:
Bonnie is making her own track. LOL!!


Katrina had a similar path..

Moved NW/NNW over the bahamas, then the High over the south pushed in and forced it WNW/W towarsd SFL and then WSW..
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Yeah, I thought so too, neon... but he came to Palm Bay, FL, in the same spot, back in 2004 for Frances and Jeanne... they both came ashore at the same spot 80 miles to the south.
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Quoting Jeff9641:
NW motion is continuing and it is becoming clear that the Keys are going to escape this one. This is looking like at Mia to West Palm landfall then exiting around Fort myers.


"It is becoming clear that the Keys are going to escape this one."? Really? We should notify Monroe EOC; I'm sure they'd be happy to stand down based on your wishful thinking...er, forecast. ;-) Seriously, Jeff, you have to stop with the northcasting; much as you might want it to, the guidance is simply not there that will steer it directly into your stretch of the coast.
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Come on guys,long as the tops of the ts's are being blown off by the ULL this thing will not amount to more than a average TS. Take a look at the latest visible images. It's hard to tell some people that on here. A lot of wishcasting goes on. But I'd have to agree with you....I don't see this being more than a moderate TS. Upper level wind forecast isn't favorable enough to allow for much more at the moment. This will mostly be a rain maker for S. Florida/ Keys.
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Quoting FLdewey:


LOL... well Jeff's repetitiveness will drive a man to curse.


This will stop once the storm passes South of Florida Hopefully lol
Member Since: August 29, 2006 Posts: 22 Comments: 1339
Quoting HurricaneNewbie:

I said logical.. Not definition.


Yeah, I noticed the "logical" word right after I posted it, sorry! Maybe someone else can explain then.
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Alot of the model guidance for 2 pm is now aiming back to the Northern Gom Louisiana
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Quoting VoodooRue:
Jim Cantore just tweeted: "In North Miami Beach to begin coverage on TD3."


Sending my socialite sis to get a photo op with him. Maybe it will help his career.
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Quoting jlp09550:


Gulf: large bay that is an arm of an ocean or sea.
Sea: refers to a large expanse of saline water connected with an ocean.
Ocean: a continuous body of water that is customarily divided into several principal oceans and smaller seas

I said logical.. Not definition.
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Quoting HurricaneNewbie:

Never understood the reasoning behind Sea, Ocean, Gulf.... please explain in logical terms
Agulf is somewhat bordered by land, an ocean is bordered by continents.
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Notice, BTW, that the HHrs have been able to fly their entire pattern down there without encountering land...
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Say goodbye to kingzfan...
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Quoting Drakoen:
TD3 moving towards the NE lol


LMAO.
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Quoting neonlazer:
Well now we know where its headed...


he should be going to south beach...north miami beach...that where the old people are..
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Quoting StonedCrab:
Looks like Mission #3 just departed...Screwing with my Google Earth
Yea google earth is messed up..Misson 2 and 3 are switched i think..cause mission 3 is just a jet dropping dropsondes(hopefully spelled right?)
Member Since: July 5, 2008 Posts: 0 Comments: 252
Quoting Drakoen:
TD3 moving towards the NE lol


I tell ya, looking at Ramsdis Visible, Bonnie is defying.

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Quoting HurricaneNewbie:

Never understood the reasoning behind Sea, Ocean, Gulf.... please explain in logical terms


Gulf: large bay that is an arm of an ocean or sea.
Sea: refers to a large expanse of saline water connected with an ocean.
Ocean: a continuous body of water that is customarily divided into several principal oceans and smaller seas
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1072. Drakoen
Quoting leo305:
@Drakoen

Do you have that beautiful close up loop of the system that you posted earlier today?


Link
Member Since: October 28, 2006 Posts: 57 Comments: 29714

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.