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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Quoting Patrap:
I got a message LSU ESL Server is overloaded.

I WUnder why?



CPU, network or too many connections?
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Quoting treehuggingsister:
Declaring Pensacola "Cantore Free Zone" and putting boom out now.


Your post doesn't make any sense since everybody in the weather community knows that Cantorie is the storm shield and if he shows up the cane will not make landfall near you . Jim has only had one storm in his long career at TWC
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That low is indeed moving away to the NW. Boom. Last night I thought this thing was dead. Now I see Cat 1 by Sat AM.
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869. unf97
Quoting StSimonsIslandGAGuy:
And thanks UNF97 :)


You are welcome! BTW SSIGuy, another scorcher today here in Jax. LOL.. Like a broken record. High expected around 96 degrees. We may get a break in the heat tomorrow and early Saturday as some spokes of energy coming through on the easterly flow from the Atlantic on the outer fringes of soon to be T.S. Bonnie brings NE FL some rain.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting BenBIogger:


Its trying to avoid the dry air to the west/southwest.
No it's just moving under the deepest convection.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Dear God,

We thank You that school starts back again in just a couple of weeks, and that you shelter us til then.

Could you create an omnipresent delete button maybe?

Thanks and amen
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Quoting Joanie38:
Good to see ya StormW!! Looks like you have it really really busy....I admire your synopses..Has anyone seen Levi????


No Levi. He was wrong on his tidbit yesterday so probably hiding out.
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On the lighter side, a friend of mine from Nebraska just asked if I knew if there would be any hurricanes near Puerto Rico in mid August. He's looking to vacation there. Hmmm...I guess living in Florida automatically makes one an expert at hurricanes and seeing the future! ;-)

A more serious question...I'm curious as to what storm strength people begin to put up their shutters? (Not worried about this one, mind you, just asking for future reference). 4 years in PB County and they are still collecting dust (and I hope that continues).
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Already planning for an indoor day for the better part of tomorrow & Saturday (live in Ft. Lauderdale). Gotta drug up the dog in case of thunderstorms which she is deathly afraid of.
Nice to see no one getting crazy in this area and so far from what I have seen on the news, they are being calm and going along with a TD or minimal TS.
Business as usual around here.
Member Since: May 20, 2009 Posts: 0 Comments: 205
Hi, Bonnie.
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Quoting Patrap:


They have a radar?
Hehe...visual satellite *grins* (and low cloud product satellite)
Member Since: July 5, 2008 Posts: 0 Comments: 252
Quoting Jeff9641:


Why does the center keep relocating North? Is this the weakness or the ULL to it's west? It seems every sat. image has a jog north.


Its trying to avoid the dry air to the west/southwest.
Member Since: March 19, 2009 Posts: 0 Comments: 1419
Quoting FLdewey:
Little whispy band showing up on GRX radar heading into treasure coast... most not hitting the ground. Brushfire in Okeechobee County has a better radar return at this moment.
Wouldn't mind a little rain here on the Treasure Coast it is Extra Humid today. Definitely more so than yesterday it felt a lot drier out.
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Quoting Jeff9641:


Why does the center keep relocating North? Is this the weakness or the ULL to it's west? It seems every sat. image has a jog north.
That's the plane's location.
Member Since: July 5, 2008 Posts: 0 Comments: 199
Declaring Pensacola "Cantore Free Zone" and putting boom out now.
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Nothing of importance in the latest HDOB message. Latest coordinates:

182200 2137N 07433W 9912 00167 0102 +255 +196 216015 015 018 004 00
Member Since: September 2, 2009 Posts: 130 Comments: 21032
BUT IM WORRIED ABOUT a slow track will this be the cASE or will it gain speed
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Quoting StormW:
*Scans blog*

*Waits for Patrap to post his great preparedness post and NOAA Weather radio stuff*


or his pic of Jim Cantore?

he did that with Alex lol
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Quoting LouisianaWoman:
Erath, huh? Delcambre here!
Well Hi there neighbor!
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Quoting StSimonsIslandGAGuy:


I agree. And I think it merits at least a 72 hour ban as well. Putting out fake advisories is wrong. I don't care if it's supposed to be sarcastic, or ironic, or whatever. It's irresponsible. And it's wrong.

It's very simple. As you understand.
There's a zero tolerance here for misrepresenting the NHC. Doesn't matter if it's humorous, sarcastic, etc.
There's just about any other area where one can slide by with sarcasm or humor. But don't misrepresent what the NHC says. If it confuses 1 person, that's 1 too many.
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Quoting neonlazer:
Now i KNOW you did not crash their server eh? Cause their visible radar is teh l33t? Actually im viewing it right now..its been loading slow for quite a while now..


They have a radar?
Member Since: July 3, 2005 Posts: 414 Comments: 125551
Quoting StormW:
*Scans blog*

*Waits for Patrap to post his great preparedness post and NOAA Weather radio stuff*
Yes he is slacking
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Tomorrow were Having the Portlight Rummage Art,Furniture and Stuff Sale here Uptown from 9-3 in NOLA.



Ill post the info in the Portlight Blog soon as Presslord gets off the phone with me here.

LOL
Member Since: July 3, 2005 Posts: 414 Comments: 125551
Quoting Patrap:
I got a message LSU ESL Server is overloaded.

I WUnder why?

Now i KNOW you did not crash their server eh?
Quoting Patrap:
I got a message LSU ESL Server is overloaded.

I WUnder why?

Cause their visible radar is teh l33t? Actually im viewing it right now..its been loading slow for quite a while now..
Member Since: July 5, 2008 Posts: 0 Comments: 252
Quoting TankHead93:
It appears from satellite imagery TD3 is strengthning and on the verge of becoming TS Bonnie. It also appears from TD3 satellite presentation that shear is weakening significantly around it. Is the later true?


Both are true. I suspect though judging by recon.. 03L might never have been a TD.
Member Since: July 8, 2005 Posts: 259 Comments: 23012
Good to see ya StormW!! Looks like you have it really really busy....I admire your synopses..Has anyone seen Levi????
Member Since: June 16, 2008 Posts: 0 Comments: 505
Thanks for all the good input yinz!
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Have there been any confirmed JIM CANTORE sightings in Florida yet? :o)
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Quoting Drakoen:
It will be interesting to see what the HH's find in the NE quadrant


Thats something I'm anxiously awaiting to see. Just based upon the current data collected so far, this may be stronger than originally thought.
Member Since: April 14, 2007 Posts: 8 Comments: 5030
Quoting newportrinative:


I thought someone mentioned that the heavy weather is going to be north of the storm. If so, doesn't that mean that SFL (Miami and maybe Broward) would get the brunt of the weather if it tracks thru the Keys or just south of?
Rain and guesty winds! Its just a depresstion Maybe a Tropical storm NOT A HURRICANE. Just get your Volka and Beer ready and enjoy a wet windy day.
Member Since: July 5, 2008 Posts: 0 Comments: 199
I got a message LSU ESL Server is overloaded.

I WUnder why?

Member Since: July 3, 2005 Posts: 414 Comments: 125551
Nah i'm not a student :)
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Quoting CybrTeddy:
Recon found some pretty convincing TS winds.. what do you all think?


Well since the NHC is giving this a 58% chance of becoming a storm be 8pm....
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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.

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