Gulf of Mexico disturbance 96L close to tropical storm status

By: Dr. Jeff Masters , 1:26 PM GMT on June 23, 2012

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An area of low pressure and heavy thunderstorms in the Central Gulf of Mexico (96L) is close to tropical depression or tropical storm status, and all interests along the Gulf of Mexico coast should pay attention to the progress of this disturbance. The disturbance has brought heavy rains to Western Cuba, South Florida, and Mexico's Yucatan Peninsula over the past two days, but the disturbance's heaviest rains are located well offshore over the Eastern Gulf of Mexico, where heavy thunderstorms are generating winds near tropical storm-force. A buoy 243 miles east of Naples, FL measured sustained winds of 31 mph, gusting to 38 mph, with 10-foot waves, at 8 am EDT Saturday morning. Our wundermap for the surrounding ocean areas shows a large region of the northern and eastern Gulf of Mexico is experiencing winds of 20 - 30 mph. Satellite-based surface wind measurements taken at 7:22 am EDT Saturday from the newly-available Oceansat-2 scatterometer, courtesy of India, showed a broad, elongated surface circulation over the Central Gulf of Mexico that was not well defined. The satellite saw top surface winds of 30 - 40 mph over the Eastern Gulf of Mexico. Visible satellite loops show that the circulation of 96L has become more defined this morning, and the heavy thunderstorm activity is slowly expanding and growing more intense. Upper-level winds out of the west are creating a moderate 10 - 20 knots of wind shear over the region. Water vapor satellite loops show a modest region of dry air over the Central Gulf of Mexico, which is interfering with development and keeping the western side of 96L's circulation free of heavy thunderstorms. Ocean temperatures are about 28.5°C (83°F) in the Central Gulf of Mexico, which is about 1°F above average. A hurricane hunter mission is scheduled to investigate 96L this afternoon to see if a tropical depression or tropical storm has formed.


Figure 1. Saturday morning satellite image of tropical disturbance 96L in the Gulf of Mexico.


Figure 2. Radar-estimated precipitation for South Florida from tropical disturbance 96L.

Forecast for 96L
Wind shear is predicted to remain in the moderate range through Sunday night, which is likely low enough to allow 96L to develop into a tropical depression or tropical storm by Sunday; NHC gave 96L a 90% chance of developing into a tropical depression by Monday morning, in their 8am EDT Tropical Weather Outlook. The future path of 96L is still unclear. The disturbance will drift slowly northwards through Sunday night, which will likely bring heavy rains of 2 - 4 inches to the Gulf Coast from Central Louisiana to Central Florida. A storm surge of 1 - 3 feet is also likely along the Southeast Louisiana coast on Sunday; coastal flood advisories have already been posted there. By Monday, the majority of the reliable models, including the ECMWF, NOGAPS, HWRF, and UKMET, agree that a ridge of high pressure will build in over the Southern U.S., forcing 96L westwards across the Gulf of Mexico and into South Texas by Wednesday. However, the GFS model, which has been our 2nd most reliable track model over the past two years (behind the ECMWF), has consistently been predicting that a trough of low pressure pushing off of the U.S. East Coast will be capable of grabbing the disturbance and accelerating it to the northeast across Florida north of Tampa Bay on Monday. The GFDL model splits the difference between these extremes, taking 96L northwards to a landfall near the Alabama/Florida border on Tuesday. Given that the majority of the models predict a westward track to Texas, that should be viewed as the most probable path for 96L, but this is a low-confidence forecast. None of the models is predicting 96L will become a hurricane, and the SHIPS model is predicting just a 4% chance of rapid intensification for 96L. Given the moderate levels of wind shear and dry air over the Gulf, only slow to modest intensification of 96L is likely over the next few days.

Jeff Masters

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Member Since: August 14, 2010 Posts: 0 Comments: 183
1295. Patrap
18:45 UTC Viz

Member Since: July 3, 2005 Posts: 426 Comments: 128874
Quoting MississippiWx:


You guys can have the bears, I'll take the beer.




LOL ok
Member Since: May 21, 2006 Posts: 5091 Comments: 115255
Where does it say anywhere that we have Debbie? NHC? Where?
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The full ATCF line:

AL, 04, 2012062318, , BEST, 0, 260N, 876W, 40, 1001, TS, 34, NEQ, 120, 120, 0, 0, 1008, 250, 120, 0, 0, L, 0, , 0, 0, DEBBY, M,
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1291. nigel20
Quoting NCHurricane2009:

Yes it is....

For those that don't know...this is a historic moment in the Atlantic tropics. Debby is the earliest fourth tropical storm in the Atlantic on record...beating Dennis of 2005 which was named on 11 PM EDT July 5...

With El Nino expected to kick in (unlike in 2005)...lets hope that we do NOT get record activity like 2005 had....

I'm thinking that we'll have no less than 12 storms...what's up NC?
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Quoting WxGeekVA:
BOOM goes the blog!


Wait until the local news starts reporting it.
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1289. ncstorm
Quoting aquak9:


Pull it off real careful, re-roll it. Go get your money back.


LOL!!!
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Hello Debby.

And oh mannnn there is a TON of moisture streaming into west florida now
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1287. aquak9
Quoting flowrida:
I am so pissed at Home Depot right now for them telling me to use Duct tape on my windows!! I spent over a hudred dollars on it and now you guys are telling me it is worthless. Now I ahve to spend hours taking this stuff back off!!!! I am literally crying right now!!!


Pull it off real careful, re-roll it. Go get your money back.
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Quoting Tazmanian:
hey Debby nic too meet you would you like to go too the bar and have a few bears with me


You guys can have the bears, I'll take the beer.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting Tazmanian:
hey Debby nic too meet you would you like to go too the bar and have a few bears with me



debby is a mean sounding name.
never liked debbys, no offense to anyone.

so is debby moving S?
or is that just me

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1284. guygee
Quoting Gorty:
Idc what anyone says, if the NHC feels like a system fits all the TC requirements ala Chris, then fine by me that they named them or number them.
Fair enough but tangential to my comment, as the National Hurricane Center was officially named in 1965.

...Oh wait, it IS Debby now...
I guess I will have to wait for another chance to make this particular point.
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BOOM goes the blog!
Member Since: September 3, 2011 Posts: 13 Comments: 3476
4-1-0
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FNMOC TC site
Member Since: June 9, 2007 Posts: 4 Comments: 15923
Quoting GTcooliebai:
Looks like we have Tropical Storm Debby! I wonder is this the first time we have had 4 named storms before July?
Quoting GTcooliebai:
Looks like we have Tropical Storm Debby! I wonder is this the first time we have had 4 named storms before July?

Yes it is....

For those that don't know...this is a historic moment in the Atlantic tropics. Debby is the earliest fourth tropical storm in the Atlantic on record...beating Dennis of 2005 which was named on 11 PM EDT July 5...

With El Nino expected to kick in (unlike in 2005)...lets hope that we do NOT get record activity like 2005 had....
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1279. Patrap
No worries and I did not mean insult you. But let's face it last time a hurricane was forecasted to hit NOLA that vast majority of the population and you local government leaders did nothing. Or too little too late.


Really?

Your so far from reality I have to laugh sport.

Gustav was the last Warned Hurricane here, and we survived and evacuated 97% of the Popualtion.

Member Since: July 3, 2005 Posts: 426 Comments: 128874
hey Debby nic too meet you would you like to go too the bar and have a few bears with me
Member Since: May 21, 2006 Posts: 5091 Comments: 115255
we got Debby!
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1276. icmoore
Quoting Jedkins01:


Prepare some potentially really, really impressive rainfall for west central Florida, bring out the canoes boys.



Do you expect about the same for the coast. I am on Madeira Beach just N of Treasure Island. The NWS hasn't been posting any big amounts expected .10 to one inch "except in thunderstorms". Sun and Sun night 1-2 inches possible. Anyway I have a rain gauge if we don't wash away :)
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now they named debby, it will fall apart, and will recover later.
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1274. Dakster
Quoting mojofearless:


Not trying to pick a fight with you - I'm just bristling a little - I'm always defensive about my hometown. There will always be people any place there's tropical weather who do not take it seriously enough. There will also be people who do, who are ahead of the curve on preparations, plans, etc. It's hard to paint the denizens of any one locale with broad brush strokes like that. We can only hope for the best.


No worries and I did not mean insult you. But let's face it last time a hurricane was forecasted to hit NOLA that vast majority of the population and you local government leaders did nothing. Or too little too late.

I get upset as an American, when an American city drops the ball. It makes all of us wherever we live in this great country look bad.

So if the GTFO alarm is sounded you all need to GTFO.
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Based on recon TS Debbie center is the swirl on visible images near 26.0N and 87.6 W
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Quoting flowrida:
I am so pissed at Home Depot right now for them telling me to use Duct tape on my windows!! I spent over a hudred dollars on it and now you guys are telling me it is worthless. Now I ahve to spend hours taking this stuff back off!!!! I am literally crying right now!!!


I read applying human tears to duct tape makes it easier to peel off. Good Luck!
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Debby looks ugly now.But will probably be more beautiful in the future.
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Levi, great analysis but Mexico and Southern Texas is NOT happening. I'm thinking between Northern Texas to Florida.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
1269. rxse7en
Quoting whipster:


8-track tape
Preferably Riding the Storm Out by REO Speedwagon.
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awwww, levi, you wrote your blog too early....

2012 will be known as fast start year from now on
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Quoting Stormchaser2007:
AL, 04, 2012062318, , BEST, 0, 260N, 876W, 40, 1001, TS




i was 1st lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115255
Quoting weatherlover94:
i dont understand why the models are showing weakening after 60 hours....is this gonna pan out?....somebody give me some details on possible strength please


It's too hard to say, because it depends on that darn ULL and how fast it moves out of the way. It's never going above cat 1 with that kind of shear, so unless the ULL gets moving away quickly it shouldn't be "too" bad on landfall.
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We got Tropical Storm Debby!
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1264. Patrap
18:58:30Z 25.167N 88.650W 973.3 mb
(~ 28.74 inHg) 278 meters
(~ 912 feet) 1004.7 mb
(~ 29.67 inHg) - From 291° at 17 knots
(From the WNW at ~ 19.5 mph) 24.1°C
(~ 75.4°F) 22.5°C
(~ 72.5°F) 18 knots
(~ 20.7 mph) 14 knots
(~ 16.1 mph) 2 mm/hr
(~ 0.08 in/hr) 13.2 knots (~ 15.2 mph)
77.8%
Time Coordinates Aircraft
Static Air Pressure Aircraft
Geopotential Height Extrapolated
Surface Pressure D-value Flight Level Wind (30 sec. Avg.) Air Temp. Dew Point Peak (10 sec. Avg.)
Flight Level Wind SFMR
Peak (10s Avg.) Sfc. Wind SFMR
Rain Rate Estimated Surface Wind (30 sec. Avg.)
Using Estimated Reduction Factor Peak Wind at Flight Level to
Est. Surface Reduction Factor

HDOB Observations

Independent Calculations from Tropical Atlantic

At 18:49:00Z (first observation), the observation was 326 miles (524 km) to the SSE (161°) from New Orleans, LA, USA.

At 18:58:30Z (last observation), the observation was 343 miles (553 km) to the SSE (165°) from New Orleans, LA, USA.
Member Since: July 3, 2005 Posts: 426 Comments: 128874
Quoting Levi32:
Good afternoon.

Blog update:

Tropical Tidbit for Saturday, June 23rd, with Video


Thanks for the info, Levi! Verry interesting!
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Quoting allancalderini:
Now if Debby forms today the record for Dennis of 2005 will likely be shattered for the earliest D storm

That's right!!!!

Quoting justsouthofnola:
gustav was no joke around here..... for those of us who stayed it was like a ghost town
night time worker here just waking up for the day
where does debbie look like shes going to go from the experienced members here?

There are a lot of opinions here. I was expecting a turn toward the west (toward TX/MX border area) 2 days ago....but this has developed further north than when I previously was blogging. I still expect a gradual westward turn due to the strength of a surface ridge that is still supposed to build in across central North America. But because of the further north postion of this thing...I think the westward turn will take it across the Lousiana coast....but no rapid development is possible with the strength of the suppressing upper-level low across the west Gulf.

I believe the models that turn this eastward toward Florida are giving way too much credence to the frontal system currently over eastern North America...
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While this storm may be driving some people nuts, I love situations like this, I love these meteorological challenges that throw everyone off because we can think about them more and it helps us explore the greater mysteries of the atmosphere. I've got to say this truly the biggest model split I've ever seen, you could almost argue that chance will decide which direction it takes. Also we could find the old low moving west and a new low forming with the deep convection that moves over Florida. That is a very plausible solution, and happens more than you might think.

BTW, already a nice steady rain falling, it is definitely a tropical rain, even though it's falling from high altitude clouds it is indeed a very warm rain. This type of rain is great to have before having torrential downpours because it allows the ground to absorb heavier rainfall thereafter, which will arrive later today.


Honestly it like like 96L is drifting south right now, or it may be performing a cyclonic loop, either way it looks like the majority of the heavy rainfall is separating towards Florida away from the low center as I suspected might happen.
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We have Debby now!!
Member Since: May 23, 2012 Posts: 0 Comments: 4722
..and the 2012 Atlantic breaks yet another record.
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43.2 mph wind - Tropical Storm on Recon.
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AL, 04, 2012062318, , BEST, 0, 260N, 876W, 40, 1001, TS
Member Since: June 9, 2007 Posts: 4 Comments: 15923
strange they named it with no sustained convec over the coc.
i though they would wait for shear to die abit and convec to cover the coc
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1255. Gorty
Quoting guygee:
To turn the tables on the old tropical climatologist saw...in the pre-satellite, pre-aerial reconnaissance era this would have been a named storm right now, but since there is only a broad center throwing off temporary meso-vortices it is not named.

The non-counting on these types of storms at least partly offsets the isolated ones we find now that might have been missed in the ship-only era...a point often missed in the recent scientific literature...even if this particular storm turns out to be Debby a little later it still illustrates the point. This dilutes the argument that the storm count now in the satellite era is vastly inflated compared to the earlier era...the existence of these potential "early overcounts" are neglected by Landsea(2007), etc.


Idc what anyone says, if the NHC feels like a system fits all the TC requirements ala Chris, then fine by me that they named them or number them.
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1254. nigel20
Good afternoon everyone...96L need some convection on its western side...
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Looks like we have Tropical Storm Debby! I wonder is this the first time we have had 4 named storms before July?
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BEGIN
NHC_ATCF
invest_al042012.invest
FSTDA
R
U
040
010
0000
201206231904
NONE
NOTIFY=ATRP
END
Member Since: June 9, 2007 Posts: 4 Comments: 15923
we have TS Debbie
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History.......First time.....4 storms by end of June.
Member Since: August 8, 2006 Posts: 0 Comments: 9265
1249. rxse7en
Looks like it's trying to wrap around a COC at ~86w 27N?
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Quoting Tazmanian:
hey all look what i found


AL, 04, 2012062318, , BEST, 0, 260N, 876W, 40, 1001, TS,


when the renumber?
i miss?
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i dont understand why the models are showing weakening after 60 hours....is this gonna pan out?....somebody give me some details on possible strength please
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Quoting Tazmanian:
hey all look what i found


AL, 04, 2012062318, , BEST, 0, 260N, 876W, 40, 1001, TS,


RENUMBER!!!!!!!!!!
Member Since: September 3, 2011 Posts: 13 Comments: 3476

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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.