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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If and a big IF wind shear does relax and the ULL pushes away. With the warm temps in the GOM.. This could really turn out to be a dangerous storm.. Big IF though.. Dry air isn't a problem, outflow is impressive, and it's got a nice tight (naked) LLC. We'll see what happens. Some of the models predicting "Hurricane" are not off if wind shear does indeed do what it's forecast to do, which is decrease.
Member Since: July 1, 2008 Posts: 13 Comments: 7437
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting Skyepony:
Recon hit a center..1001.8 mb
(~ 29.58 inHg) ~25.917N 87.850W, winds go SW..


Those coords are right where the naked swirl is.
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17:18:30Z 25.767N 87.817W 980.8 mb
(~ 28.96 inHg) 190 meters
(~ 623 feet) 1002.3 mb
(~ 29.60 inHg) - From 254° at 8 knots
(From the WSW at ~ 9.2 mph) 24.0°C
(~ 75.2°F) 23.8°C
(~ 74.8°F) 9 knots
(~ 10.3 mph) 9 knots
(~ 10.3 mph) 1 mm/hr
(~ 0.04 in/hr) 8.0 knots (~ 9.2 mph)
100.0%
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 17:09:00Z (first observation), the observation was 290 miles (467 km) to the SSE (154°) from New Orleans, LA, USA.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
741. Skyepony (Mod)
Recon fell to ~ 614 feet in the center.
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Pressure is down to 1001mb, not bad. Starting to get some west-sw winds.
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Quoting Drakoen:


Hey! I'm taking summer classes at FSU.


Good....So you will be in town if we get some squalls tomorrow and Monday. I will be cleaning the branches and limbs in my yard around Wednesday.....You wanna help?.....Lol........Just kidding.
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Quoting CybrTeddy:
Personally, I don't think they're going to find a closed circulation with 96L, maybe at the very last pass.
lets stay positive :)
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737. 900MB
Quoting reedzone:
You all are funny... really... no closed low???



Gosh some of you are just... lol.

Recon should find a sheared 40 mph. Tropical Storm.


Looks pretty sheared to me! A naked swirl that seems to be going SW.
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736. Skyepony (Mod)
Recon hit a center..1001.8 mb
(~ 29.58 inHg) ~25.917N 87.850W, winds go SW..
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I'm not sure I've ever seen a system spin off so many low level vorticies in such a short period of time.
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Member Since: July 3, 2005 Posts: 428 Comments: 129841
About Ike, maybe he wasn't banned. His blog still shows up. Hope nothing happened with his health.

Link
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Center of one swirl found with a 1001.8mb pressure minimum and nearly calm winds, though given the SW motion of the swirl it may not be the true mean center of the system.

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Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting TropicalWxBlogger:


Im not going to agree there. Most who has been through 100-110mph windspeeds isnt going to agree its minimal, neither will the Ike veterans. Or the Floyd veterans. Or the Isabel veterans.

:)
...In meteorological terms its a minimal hurricane. That is all I am going to say about that.
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Member Since: July 3, 2005 Posts: 428 Comments: 129841
could hurricane anita from 1977 be an anologue??
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Quoting Drakoen:
There are some signs that 96L continues to organize with popcorn convection developing south of the center of circulation.



I see it, I see it.
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Member Since: May 23, 2012 Posts: 0 Comments: 4984
Quoting weathermanwannabe:


Hey Drak. Hope all is well with you at FSU. You are probably at home for the Summer but that low circulation is moving from East to West here in Tallahassee......... :)


Hey! I'm taking summer classes at FSU.
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There are some signs that 96L continues to organize with popcorn convection developing south of the center of circulation.

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Quoting reedzone:
You all are funny... really... no closed low???



Gosh some of you are just... lol.

Recon should find a sheared 40 mph. Tropical Storm.

96L would be massive if it had all its quadrants filled with convection
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Station 42003
NDBC
Location: 26.044N 85.612W
Date: Sat, 23 Jun 2012 16:50:00 UTC
Winds: SE (140°) at 31.1 kt gusting to 38.9 kt
Significant Wave Height: 13.8 ft
Dominant Wave Period: 11 sec
Mean Wave Direction: SSE (163°)
Atmospheric Pressure: 29.65 in and falling
Air Temperature: 78.6 F
Water Temperature: 82.4 F
Member Since: September 3, 2011 Posts: 13 Comments: 3477
Quoting reedzone:
You all are funny... really... no closed low???



Gosh some of you are just... lol.

Recon should find a sheared 40 mph. Tropical Storm.




so ture they are funny the nhc would not be saying a TS could fourm later today if it did not have a close low
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting Drakoen:


The physics is justified.


Hey Drak. Hope all is well with you at FSU. You are probably at home for the Summer but that low circulation is moving from East to West here in Tallahassee......... :)
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Recon punched the northern eddy and the pressure fell to 1001mbs

Member Since: June 9, 2007 Posts: 4 Comments: 15950
717. Skyepony (Mod)
This is a much better way to see that same OSCAT, where you can see both circulations this is about 12hrs old.
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Looks like the NWS office in Melbourne is having the same issues as us bloggers regarding 96L. Interesting take on things nonetheless.

Link
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Quoting WxGeekVA:




It says 16:14 UTC and it's 17:20 UTC right now...


that will always show current time, the times of the pass are the purple numbers on the bottom
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Quoting jeebsa:
Does the GFS model show 2 lows in its run or 1?
2 storms
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Quoting louisianaboy444:


I think The Upper Texas/ Louisiana/ Mississippi coasts may have to watch this closely....if it stalls and meanders right off the coast a brief landfall could be possible


I think you guys in Louisiana should definitely pay attention. Even if it doesn't make landfall there, it appears that you could get pounded with rain and wind since a lot of the models bring her so far north.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
You all are funny... really... no closed low???



Gosh some of you are just... lol.

Recon should find a sheared 40 mph. Tropical Storm.
Member Since: July 1, 2008 Posts: 13 Comments: 7437
Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 23rd day of the month at 17:06Z
Date: June 23, 2012
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 302)
Mission Purpose: Investigate first suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 09


17:08:30Z 26.233N 88.000W 970.9 mb
(~ 28.67 inHg) 288 meters
(~ 945 feet) - - From 62 at 29 knots
(From the ENE at ~ 33.3 mph) 20.5C*
(~ 68.9F*) -* 30 knots
(~ 34.5 mph) 32 knots
(~ 36.8 mph) 5 mm/hr
(~ 0.20 in/hr) 30.9 knots (~ 35.6 mph)
106.7%
Time Coordinates Aircraft
Static Air Pressure Aircraft
Geopotential Height Extrapolated
Surface Pressure

At 17:08:30Z (last observation), the observation was 288 miles (463 km) to the SSE (154) from New Orleans, LA, USA.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
Quoting Tropicsweatherpr:


Thet is from 11 PM EDT if you look at the bottom.


Quoting Levi32:


That pass is 15 hours old.


Edit N/M
Member Since: September 3, 2011 Posts: 13 Comments: 3477
Does the GFS model show 2 lows in its run or 1?
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Nvm.
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Category One Hurricane

Maximum Sustained Wind Speed: 74-95 miles per hour
Damage Category: Minimal
Approximate Pressure: Above 980 mb
Approximate Storm Surge: 3-5 feet
Examples: Hurricane Lili (2002) in Louisiana; Hurricane Gaston (2004) in South Carolina

Category Two Hurricane

Maximum Sustained Wind Speed: 96-110 miles per hour
Damage Category: Moderate
Approximate Pressure: 979-965 mb
Approximate Storm Surge: 6-8 feet
Example: Hurricane Isabel (2003) in North Carolina

Category Three Hurricane

Maximum Sustained Wind Speed: 111-129 miles per hour
Damage Category: Extensive
Approximate Pressure: 964-945 mb
Approximate Storm Surge: 9-12 feet
Examples: Hurricane Katrina (2005) in Louisiana; Hurricane Jeanne (2004) in Florida; Hurricane Ivan (2004) in Alabama

Category Four Hurricane

Maximum Sustained Wind Speed: 130-156 miles per hour
Damage Category: Extreme
Approximate Pressure: 944-920 mb
Approximate Storm Surge: 13-18 feet
Example: Hurricane Charley (2004) in Florida; Hurricane Iniki (1992) in Hawaii; the Galveston Hurricane (1900) in Texas

Category Five Hurricane

Maximum Sustained Wind Speed: 157 miles per hour and higher
Damage Category: Catastrophic
Approximate Pressure: Below 920 mb
Approximate Storm Surge: More than 18 feet
Examples: Only three Category 5 hurricanes have struck the United States since records began: The Labor Day Hurricane (1935) in the Florida Keyes, Hurricane Camille (1969) near the mouth of the Mississippi River, and Hurricane Andrew (1992) in Florida
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Quoting WxGeekVA:
ASCAT shows nothing near a closed low yet:



That is from 11:45 PM EDT if you look at the bottom.
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Quoting WxGeekVA:
ASCAT shows nothing near a closed low yet:



That pass is 15 hours old.
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Can someone post the link to the live recon to open in Google Earth!!
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Rain chances for my area is only 20% through Monday and 0% Tuesday. I am assuming this will change.
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.
Member Since: September 3, 2011 Posts: 13 Comments: 3477
Quoting louisianaboy444:


LOL So much for an upgrade i think the HWRF model has pointed at every state on the gulf coast

The environment and details of the tropical systems change every day and with those new details the model needs to change accordingly, i dont see how the model could say from this one day that this will be the exact track of the system over the coming days. Environment changes...
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Quoting MississippiWx:


So are you trying to say its plausible? I just don't see it.


The physics is justified.
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I second Cat, nice to see some of the older members appearing. It isnt raining any more in miami, but the cloud cover is fairly complete.

Interesting watching the models on this. The last time i remember the models did this the outlier ended up being a second system that developed.


Drak, good to see you, hope school is going well for you.
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Quoting LargoFl:
The exposed LLC is racing away to the SW away from the convection.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting FSUCOOPman:


That takes it right over the area that just had a ridiculous amount of rain in a short period of time.



True; but the competing scenario (to the East) as being discussed by some is the timing of the trof and if she gets picked up by it. I suppose the general rule of thumb of weaker to the West - stronger to the East might be in play here. I don't want to speculate either way but wait until the models runs tonight after the Hunters take their samples and data.....Given the short time frames here either way I will say this; the NHC three-day track is very accurate, so I will leave the steering to them once they initiate a true center for the models.
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Quoting Stormchaser2007:
Nice cat 1.
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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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