Tropical depression forming over the Bahamas

By: Dr. Jeff Masters , 1:29 PM GMT on July 22, 2010

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A tropical wave (Invest 97L) over the eastern Bahama Islands has developed a closed circulation at the surface, and has become a tropical depression or tropical storm. Here is the text of the Special Tropical Weather Outlook from NHC at 8:25am EDT today:

Visible satellite images and observations from the Bahamas indicate that the area of low pressure in the southeastern Bahamas has become better organized and a closed circulation has formed. Advisories on a tropical depression or a tropical storm will be initiated at 11 am EDT...1500 UTC today. This advisory will likely include tropical storm watches and warnings for portions of the Bahamas and southern Florida.

Satellite images of 97L show a modest area of heavy thunderstorms that have slowly increased in intensity and areal coverage this morning. Water vapor satellite loops show a large area of dry air lies to the west of 97L, over Florida. This dry air is associated with a large upper-level low pressure system that is moving west at about the same speed 97L is. The counter-clockwise flow of air around the upper low is bringing about 20 knots of wind shear to 97L. Surface observations in the Bahamas and several nearby ships have shown top winds in 97L 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 97L
The storm is in a fairly straightforward steering current environment, and 97L 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 97L over the next two days. The location of 97L'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 97L
The primary detriment to development of 97L 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 97L, it will bring wind shear of about 20 knots and dry air into the storm. This will limit the intensification potential of 97L to no more than about 10 - 20 mph per day. If the upper-level low picks up speed and pulls away from 97L, the storm may be able to intensify at a faster rate. None of the computer models is calling for that to happen, but it is possible. I put the odds of 97L 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.

I'll have an update after NHC releases their 11am advisory package.

Jeff Masters

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Quoting hurrkat05:
just like i been saying bonnie can't intensify with the low to the west and the shear 30-40 knots..also the dry air thats going to be sucked into the system will disrupt bonnie.....bonnie will be no more then a weak tropical storm and as long as the shear stays around dr i have to disagree with you i give bonnie no chance of becoming a hurricane in the gom...


Well, he finally got a prediction right: No more than 10 min prior to his post, he said

"...im sure when dr masters comes on her will set all you straigh whats ahead for tropical storm bonnie once she gets close to the keys...then we will have people arguibg with him ...lol well this is a weather blog i think..."
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ARE YOU SERIOUS? wow was not exspecting that answer! well maybe I should go around the area and see if the ants have been acting a bit weird lol... thanks for responding even though I really did not expect to hear that
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One thing you all need to realize, not just the warm waters but the size of TD3, it's small and small systems tend to surprise us more then larger ones like 98L.
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Quoting MiamiHurricanes09:
The Bahamas and south Florida will likely be under tropical storm warnings... I'm also eagerly awaiting the cone of uncertainty.


give it 10 more minutes
Member Since: July 21, 2010 Posts: 0 Comments: 1181
Quoting 7544:
local news just said that td 3 is getting stronger and will see ts warnings go up for so fla i at 11 am also said it has alot of moisture to get even stronger as the day goes on thats warniings not wathes

where do you live and what news was that
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Quoting hurrkat05:
WELL STORM I AGREE WITH YOU I BEEN SAYING THAT ALL MORNING TO MUCH DRY AIR AND STRONG WIND SHEAR...BONNIE WILL BE NO MORE THEN A WEAK TROPICAL STORM...


Question for you hurrikat. Is there an anticyclone over this storm? How hot are the waters in the GOM, is the shear low??
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting earthlydragonfly:


Did someone hear something?


LOL, that was good!
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I think NHC will play conservative as usual and give it TD status, and wait until a plane investigates its true intensity. Expect TS Warning probably from Fort Pierce to Dry Tortugas (just a guess).
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whs2012 2:31 PM GMT on July 22, 2010
I think TD3 (Bonnie) will be a strong cat 1, weak cat 2, and make landfall anywhere from central texas, to nola....maybe a little bit more east, but I doubt it..




I agree but I dont think there is much concensus on this...
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-80C cloudtops starting to pop up in TD3.
Member Since: July 8, 2005 Posts: 259 Comments: 24576
The Bahamas and south Florida will likely be under tropical storm warnings... I'm also eagerly awaiting the cone of uncertainty.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
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Quoting hurrkat05:
well i will check my latest data coming out at 12noon and i will see if bonnie has any new life beyond fla...later guys and storm take care..


HAVE A GREAT DAY!
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Quoting tropicfreak:


No one is responding.




So? A whole bunch of my posts, and I'm sure other peoples too don't get responded to. Develope some thicker skin. It'll serve you well.


As for the poll.

Bonnie I believe. But Iv'e been wrong plenty of times before!
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Sounds like someone's caps lock tab is broken..
Member Since: July 8, 2005 Posts: 259 Comments: 24576
When the hurricane hunters going to visit Bonny?
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And the predictions for Tampa Bay are.......???

Question: When was the last time Tampa Bay was directly hit? And what kind of atmospheric armor do we have?
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300. 7544
wow destin jeff td3 or ts bonnie getting srtonger and more compact as we are bloging may have to up my prediction to 60 mph before reaching fla then i would agree with tampa at 50% of being a cat 1 beforeland as tampa posted anything is posssible at this point and short amount of time to watch this flurrish
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Quoting 900MB:
Poll time!

a- TD is declared
b- Bonnie is declared


Looks more like a TD right now, recon should find stronger winds which should upgrade to TS by 5 p.m.
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I agree.. but I dont think we have concensus on this..
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Quoting MiamiHurricanes09:
Probably the "A option for now, but once recon gets in there Bonnie is likely.


I just have a feeling that recon will find a much stronger system than people think.
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Quoting 900MB:
Poll time!

a- TD is declared
b- Bonnie is declared



B
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Quoting ATL:

Bonnie shouldn't have much trouble with this unless she stalls out for some odd reason. A TS/weak hurricane can sustain itself fairly easily on low tropical heat content as long as upper levels are favorable.


Agree. I think upwelling of this cold water close to, but below, the surface will have more impact on a train of consecutive storms than the first one, unless it stalls.
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Quoting ho77yw00d:
... To all my lovely experts and want to be experts (your still good), so in youe best opinon is south florida, such as Fort Myers out of the question for seeing any affects from 97L?


Not an Expert but, South Florida including Fort Myers will feel nearly the full affects of the future to be named Bonnie. The North side of the Storm is the bad side Currently....your gonna get just a ton of rain and Tropical Storm force winds and be prepared for possible Hurricane type conditions.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting 900MB:
Poll time!

a- TD is declared
b- Bonnie is declared


Im thinking TD. then move it to TS tonight. Not sure how far they want to stretch their necks..
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Quoting Waltanater:
It looks like the high density winds may be steering it north into South Florida!


Like on your avatar.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting tropicfreak:
AM I ON IGNORE???


Not yet...lol
Member Since: October 30, 2007 Posts: 0 Comments: 270
Quoting 900MB:
Poll time!

a- TD is declared
b- Bonnie is declared
Probably the "A" option for now, but once recon gets in there Bonnie is likely.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting hurrkat05:
GOOD OBSERVATION TEDDY I AGREE WITH YOU ON THAT WHAT I DIN'T AGREE WITH YOU GUYS IS THE STRENGTHING PART...YOU WILL HAVE NO MORE THEN A WEAK TROPICAL STORM AT BEST..BONNIE HAS NO CHANCE OF REACHING HURRICANE FORCE IN THE GOM...TOY MANY NEGATIVE FACTORS AHEAD OF HER...
please stop saying the same thing over and over once is enough
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Opal too!
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Quoting 900MB:
Poll time!

a- TD is declared
b- Bonnie is declared


Bonnie.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting PensacolaDoug:


Not on mine. But you don't gotta yell.


No one is responding.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
F5..F5..F5..
Member Since: July 8, 2005 Posts: 259 Comments: 24576
282. 900MB
Poll time!

a- TD is declared
b- Bonnie is declared
Member Since: June 11, 2006 Posts: 0 Comments: 684
Quoting AllStar17:


Usually is the case.

I remember Darby in the EPAC earlier this year was only projected to become a 50-60 mph Tropical Storm, and it became a 115 mph major hurricane.


Same with Alex, was predicted to only be a moderate TS and it became a borderline Category 2/3 hurricane when it hit Mexico.
Member Since: July 8, 2005 Posts: 259 Comments: 24576
Quoting tropicfreak:
AM I ON IGNORE???


Did someone hear something?
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if the conditions were better we would have a problem. 75L wants to take off so bad.
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Quoting hurrkat05:
WELL STORM I AGREE WITH YOU I BEEN SAYING THAT ALL MORNING TO MUCH DRY AIR AND STRONG WIND SHEAR...BONNIE WILL BE NO MORE THEN A WEAK TROPICAL STORM...


UGGGGGGGHHH I can't take this. *POOF*
Member Since: September 2, 2006 Posts: 110 Comments: 6878
It looks like the high density winds may be steering it north into South Florida!
Member Since: May 16, 2010 Posts: 0 Comments: 1472
Quoting chrisdscane:


ive said the same thing im not impressed either with the conditions or the way its looking right now im in west kendall,fl and im just putting my umbrella in the car


Ignore him, hurrkat is a troll.
Member Since: July 8, 2005 Posts: 259 Comments: 24576
Quoting nolesjeff:


Maybe if the non-fla residents would lay off the fla residents all would be good. I am sure you have heard of Andrew and Charley:?


Why does everyone forget Ivan?
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Quoting tropicfreak:
AM I ON IGNORE???


Not on mine. But you don't gotta yell.
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Quoting DestinJeff:
This thing is a veritable BEAST I tell you!


Seriously, if I'm in S FL, I am very aware of the potential for more weather out of TD3 than maybe some expected. Always concerned about under forecasting intensity.


Usually is the case.

I remember Darby in the EPAC earlier this year was only projected to become a 50-60 mph Tropical Storm, and it became a 115 mph major hurricane.
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Quoting hurrkat05:
WELL STORM I AGREE WITH YOU I BEEN SAYING THAT ALL MORNING TO MUCH DRY AIR AND STRONG WIND SHEAR...BONNIE WILL BE NO MORE THEN A WEAK TROPICAL STORM...


ive said the same thing im not impressed either with the conditions or the way its looking right now im in west kendall,fl and im just putting my umbrella in the car
Member Since: July 21, 2010 Posts: 0 Comments: 1181

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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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