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 Hurricanes101:


97L is well organized now, it needs to fill in the west side, but for a TD/weak TS it is well organized


ya but im still not impressed its "heart" (coc) is very vunerable right now
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Quoting btwntx08:
hurrkat is just a painful liar ull is moving away faster and td3 is very slow he better make more crow ready hurrkat


Ignore him. He will be banned soon enough.
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My prediction for a hurricane stands at 90% since last night. There is a lot of warm water ahead and the land passage seems unlikely except for minor interference. Also, the upper level low should continue to outpace Bonnie as the upper low will arive on the Texas coastline as early as Saturday according to NOAA in Midland, Texas.
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looks like the GFDL and HWRF were wrong lol
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Quoting reedzone:


It's starting to have that appearance that "K" had when she became a TD. Remember "K" developed next to an ULL to.. Not saying it's going to happen the same way, but if it slows down or the ULL speeds up, with those warm sea surface temps, we could have a major problem in the Gulf.


That's what I'm thinking too. If you look at the water vapor loop the ULL is already in S Florida moving SW pretty fast instead of West into the GOM and into the path of 97L like some suggested. If the ULL keeps going SW and clears out of 97L's path this thing could ramp up a lot faster than previously thought. Time will tell.
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through the FL Keys as a cat 3....

pucker up time for northern Gulf coast...

a cat 5 is NOT out of the realm of possibility.
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Quoting chrisdscane:
still not organized though wont be surprised if its td3 instead of bonnie


TD 3 is well organized now, it needs to fill in the west side, but for a TD/weak TS it is well organized
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Trying to keep up with all these posts is making me a......Dramamine Caster.
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I place the COC of TD #3 at 22.2N and 74.6W, with the convection located to the east and north of the center. While currently lopsided, IMO, it is showing every indication of becoming better organized.... IMO this will become TS Bonnie within 24 hours.
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Thanks for the update Dr. Masters…

Good Morning StormW (thanks for the update as well), Ike, and Patrick…hope we have a good day of discussions…versus the stormy chaos of late.

Very Respectfully,

Jon
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Quoting reedzone:


It's starting to have that appearance that "K" had when she became a TD. Remember "K" developed next to an ULL to.. Not saying it's going to happen the same way, but if it slows down or the ULL speeds up, with those warm sea surface temps, we could have a major problem in the Gulf.
I have been feeling the same way about 97L one the more it evolves
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Quoting tropicfreak:


Wishful thinking for a down- you know what but the reality is if you have a TS sitting in the hot tub waters of the GOM you can bet it will explode.
Not if upper level winds are unfavorable.
Wonder if this ridge is gonna protect us in the the Presslina's all summer...
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Quoting TampaSpin:


I believe that would be very inaccurate IMO.....the slower it moves the stronger it will come and the more Northward it would go also!
Yeah at first I thought that the stronger it would get the more poleward it would go, but a ridge to the north wouldn't allow for it to go anymore north than southern Florida.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
still not organized though wont be surprised if its td3 instead of bonnie
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Quoting BradentonBrew:


Absoultely. It's ok to be any kind of caster you want. Without different ideas, it wouldnt be much of a discussion.


:-)
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Quoting CybrTeddy:


I'm a Space program fan.. can I be the Cape Canaveral caster?


Absoultely. It's ok to be any kind of caster you want. Without different ideas, it wouldnt be much of a discussion.
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Quoting AllStar17:


Probably. However, I can tell the satellite he had on the screen was old.

I have no idea why they put recorded shows on......VERY lame.


they always say WUWA is on at i think its 5 and 10 central.
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Quoting AllStar17:


That is the recorded Wake Up With Al from 6 am.....it is NOT live, I do not believe.


I would not believe the Weather Channel even if they were live at the center of the storm.
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Quoting MiamiHurricanes09:
Not only that but the slower it goes the less chance it has of moving into south Florida but rather through the keys or straights.


I believe that would be very inaccurate IMO.....the slower it moves the stronger it will come and the more Northward it would go also!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting bjdsrq:
I have ants everywhere this morning....



There's never an "Orkin Man" around when ya need him!
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Quoting HURRICANE JUNKY;


You are right about that. The local S. FL mets are pretty darned good. Here in Ft. Myers, Robert Van Winkle, Jim Reif and Jim Farrell were all over Charley's course change before TWC or NHC ever gave us any indication it was happening. Since that storm I have a newfound respect for the talents of our local mets.

Good post.. I remember Jim Reif in the 1970,s right after graduating from Penn State. He Worked at WINK for many years. Jim Farrel was at WBBH in the mid 80,s(maybe earlier) I was tracking Hurricane Gilbert in 1988 with him and Mike Potter at T.V.20 in Fort Myers.
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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...


Wishful thinking for a down- you know what but the reality is if you have a TS sitting in the hot tub waters of the GOM you can bet it will explode.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting BahaHurican:
I don't like the sound of that.... :o(


Hey Baha,

Remember the deal - you keep it on your side...
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Quoting whs2012:
Will the NHC come out with the cone of uncertainty around 11PM CST or EST?


EST.. At least I would assume so.
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Quoting reedzone:


It's starting to have that appearance that "K" had when she became a TD. Remember "K" developed next to an ULL to.. Not saying it's going to happen the same way, but if it slows down or the ULL speeds up, with those warm sea surface temps, we could have a major problem in the Gulf.
Yep. I however am still thinking of a southern Florida landfall, but more towards the keys rather than the mainland. Either way, the mainland will be on the "dirty side".
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Went to bed late last nite thinking we might have a Closed Low last nite and possibly Bonnie......i believe that asumption is correct. This strengthing will also allow Bonnie to move slightly North some also...
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting reedzone:


It's starting to have that appearance that "K" had when she became a TD. Remember "K" developed next to an ULL to.. Not saying it's going to happen the same way, but if it slows down or the ULL speeds up, with those warm sea surface temps, we could have a major problem in the Gulf.


shhhh!!!!! ;)
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I have ants everywhere this morning....
Member Since: July 26, 2003 Posts: 3 Comments: 428
Looks like TD3 is developing a feeder band between Cuba and Haiti, but it is still struggling with dry air on its west side. The recent burst of convection over the center just died, I am guessing due to dry air intrusion from the west-southwest.
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Wow, look how quickly the blog has picked up with this morning's special statement from the NHC! Everytime I refresh there's 50 new posts LOL! Anyways this is going to be a fun one to forecast strength wise, how little or much affect is the ULL going to have on it? What happens to a ULL sandwiched between two tropical systems, what if it just gets absorbed into one or the other or goes poof? Too many variables at play here, should be fun to watch all the craziness posted on the blog in the next few days!
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Quoting Drakoen:
Looks like TD3 has building some convection in its northwestern quadrant. Also looks to have slowed down some.
GOES satellite animation
I don't like the sound of that.... :o(
Member Since: October 25, 2005 Posts: 19 Comments: 22725
Quoting MiamiHurricanes09:
Not only that but the slower it goes the less chance it has of moving into south Florida but rather through the keys or straights.


It's starting to have that appearance that "K" had when she became a TD. Remember "K" developed next to an ULL to.. Not saying it's going to happen the same way, but if it slows down or the ULL speeds up, with those warm sea surface temps, we could have a major problem in the Gulf.
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The advisory should come out within the hour.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Hurricanes12:
Will new models come out with the 11 AM EST advisory?
The next batch of models will come out at 2PM EDT.
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Quoting AussieStorm:

So is it TD3 now or still 97L or both?


Its been a TD for over an hour..
its probably Bonnie already.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting GeoffreyWPB:


Good morning Drak...Do you see watches/warnings reaching up to our neck of the woods?


Yes, I do. South Florida will be on the "dirty side" of the system. So even if this go through the key we should see deteriorating weather conditions as well.
Member Since: October 28, 2006 Posts: 57 Comments: 30814

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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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