Gulf Distubance 91L More Organized, Headed Towards Florida

By: Dr. Jeff Masters , 5:21 PM GMT on June 05, 2013

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Tropical disturbance 91L in the Southeast Gulf of Mexico has gotten more organized over the past day, and the Hurricane Hunters are scheduled to fly their first mission of 2013 this afternoon to see if the storm is becoming a tropical depression. Buoy 42003 near the heaviest thunderstorms of 91L measured sustained winds of 33 mph, gusting to 41 mph this morning at 2 am EDT. Satellite loops show a lopsided storm, with a large area of heavy thunderstorms on the east side of a center of circulation that is trying to develop at the edge of a region of dry air that covers the entire Central and Western Gulf of Mexico. This dry air is due to a trough of low pressure whose upper level winds are also creating moderate wind shear of 15 - 20 knots. Wind shear is forecast to rise to the high range, by Thursday, and 91L is forecast to make landfall along the northern Gulf Coast of Florida on Thursday evening, so the system has a short window of time to intensify. NHC is giving the disturbance a 50% chance of developing into a tropical cyclone. I put these odds higher, at 60%. If it does develop, it will be difficult for 91L to get any stronger than a 45 mph tropical storm in the Gulf of Mexico. Regardless of whether or not 91L develops into a tropical depression, heavy rains will be the storm's main threat. A swath from Florida to New England can expect 2 - 4" of rain. A few isolated EF-0 tornadoes will also be possible along the northern Florida Gulf Coast. A storm surge of 1 - 3 feet is predicted for Cedar Key, Florida, and rip currents will be a risk for swimmers who brave the high surf. Fort Pickens, located in Gulf Islands National Seashore on a barrier island offshore from Pensacola, Florida, has been closed to visitors due to the approaching storm. A single 2-lane road vulnerable to storm surges runs to Fort Pickens. Officials want to prevent a repeat of the situation that occurred in September 2011, when Tropical Storm Lee pushed a storm surge over the road that blocked it with sand and debris, trapping numerous campers and visitors in Fort Pickens.

The storm is getting caught up in a trough of low pressure that will pull it quickly to the north-northeast beginning on Thursday, with the center expected to move over coastal North Carolina on Friday afternoon, and over Massachusetts on Friday night. If 91L does manage to become a tropical storm before making landfall on Thursday, it will quickly degenerate into a regular extratropical low pressure system before moving up the East Coast.


Figure 1. Latest satellite image of Invest 91L.


Figure 2. Predicted precipitation for the 7-day period ending June 12, 2013 from the NWS/NCEP. A swath of 2 - 4" of rain is expected from Florida to New England from 91L.

Jeff Masters

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30mph winds.....no andrea support yet

td1 maybe...should shift tracks waaaaay east.....SE rainfall amounts will go down to .5 - 1.5"

mostly in FL and the atlantic coast.
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Quoting GTcooliebai:
Blogs about to go into hyperdrive.

If only I understood what half this stuff means...or even cared. :-) I guess the NHC will give us an official update soon so the stormgasms can begin.
Member Since: October 2, 2004 Posts: 0 Comments: 13464
1004.8 and 1005MB nOW!!!!!!!!
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428. 7544
Quoting GeorgiaStormz:
models gonna shift waaaaaay east.


agree ans more south too imo saying
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Quoting MAweatherboy1:
If this isn't a TD, it sure is close. We may very well have TD 1 or Andrea before the day is done.

Agreed.
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New LLC motion is NNE by NE at 5-10.

Guidance will be shifting east quite a bit, tampa may get its storm after all.
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Quoting GTcooliebai:
Blogs about to go into hyperdrive.

It is already in hyperdrive
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424. 7544
Quoting Skyepony:

They just found another ssw at 24.783N 87.700W. There was another 10 mins west of there too.


thankyou

Quoting WeatherNerdPR:
Can't wait to see what winds they find in the main mass of convection.


ill guess about 45mph imo the promblem i see it moving further east the last couple of hours see what the recon finds .
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Quoting MiamiHurricanes09:
1004.8mb.


193000 2506N 08631W 9827 00193 0048 231 223 208028 030 024 000 03

Along with plenty of 1005mb readings.

192930 2505N 08633W 9827 00197 0050 230 220 216027 028 021 000 00

Not bad at all.


Yep 1005mbs...question now does the MLC move NE and leave the LLC behind...thus keeping this from getting better organized tonight (aka GFS).... we will see
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1004 mb over new COC we have a closed low now
Member Since: May 28, 2013 Posts: 0 Comments: 349
Latest HDOB shows 1004.3 MB and still falling. Possible closed low I will wait for wind vectors to confirm.

Very close to 25.5 by 85.5
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Not sure if I would call this closed:

Member Since: December 21, 2007 Posts: 13 Comments: 3044
If this isn't a TD, it sure is close. We may very well have TD 1 or Andrea before the day is done.
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Quoting Levi32:
A very broad MSLP minimum is being found (long flight time at the same pressure, see 2nd image below) with lowest values around 1006mb and weak/variable winds. Expect TS force easily on eastern side under the convection. Center relocation will likely be found and is expected with this type of storm. Alberto 2006 did it just like this.

Don't forget you can view live recon plots and data tables here







Yes ,Levi I'm watching on your page!!! :)
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models gonna shift waaaaaay east.
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New RECCO message pressure now at exactly 1006MB still falling


Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 5th day of the month at 19:30Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Mission Purpose: Investigate first suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 07

Mandatory Data...

Observation Time: Wednesday, 19:26Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 25.0N 86.8W
Location: 316 miles (509 km) to the W (276°) from Key West, FL, USA.
Turbulence: None
Conditions Along Flight Route: In and out of clouds
Pressure Altitude: 210 meters
Flight Level Wind: From 250° at 16 knots (From the WSW at ~ 18.4 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 21°C
Flight Level Dew Point: 21°C
Weather (within 30 nautical miles): Shower(s) (continuous or intermittent precipitation - from cumuliform clouds)
Mean Sea Level Pressure (MSLP): 1006 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 260° at 15 knots (From the W at ~ 17.2 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 13 knots (~ 15.0mph)
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Strong winds...
Member Since: August 14, 2008 Posts: 4 Comments: 4948
1004.8mb.


193000 2506N 08631W 9827 00193 0048 231 223 208028 030 024 000 03

Along with plenty of 1005mb readings.

192930 2505N 08633W 9827 00197 0050 230 220 216027 028 021 000 00

Not bad at all.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
looks like we have a closed low, 1004mb
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Quoting Levi32:
A very broad MSLP minimum is being found (long flight time at the same pressure, see 2nd image below) with lowest values around 1006mb and weak/variable winds. Expect TS force easily on eastern side under the convection. Center relocation will likely be found and is expected with this type of storm. Alberto 2006 did it just like this.

Don't forget you can view live recon plots and data tables here








I am in agreement 100% with the above, supports existing satellite presentation very well.
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Wind direction is changing now and is supporting the area where we think there may be a new center.

Pressure still falling.

Time: 19:25:30Z
Coordinates: 25.0167N 86.8667W
Acft. Static Air Press: 988.1 mb (~ 29.18 inHg)
Acft. Geopotential Hgt: 159 meters (~ 522 feet)
Extrap. Sfc. Press: 1006.2 mb (~ 29.71 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 253° at 11 knots (From the WSW at ~ 12.6 mph)
Air Temp: 23.0°C (~ 73.4°F)
Dew Pt: 21.5°C (~ 70.7°F)
Peak (10s) Flt. Lvl. Wind: 13 knots (~ 14.9 mph)
SFMR Peak (10s) Sfc. Wind: 10 knots* (~ 11.5 mph*)
SFMR Rain Rate: 1 mm/hr* (~ 0.04 in/hr*)
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Can't wait to see what winds they find in the main mass of convection.
Member Since: July 7, 2010 Posts: 0 Comments: 5648
A very broad MSLP minimum is being found (long flight time at the same pressure, see 2nd image below) with lowest values around 1006mb and weak/variable winds. Expect TS force easily on eastern side under the convection. Center relocation will likely be found and is expected with this type of storm. Alberto 2006 did it just like this.

Don't forget you can view live recon plots and data tables here





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Quoting GTcooliebai:
Blogs about to go into hyperdrive.



Ludicrous speed!
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Near the new center 1006 mb.

New Center should be at 25.5 north and 86.5 west.

19:25:00Z 25.017N 86.900W 987.4 mb
(~ 29.16 inHg) 164 meters
(~ 538 feet) 1006.2 mb
(~ 29.71 inHg) - From 249 at 8 knots
(From the WSW at ~ 9.2 mph) 23.3C
(~ 73.9F) 21.4C
(~ 70.5F) 8 knots
(~ 9.2 mph) 7 knots
(~ 8.0 mph) 1 mm/hr
(~ 0.04 in/hr) 7.0 knots (~ 8.0 mph)
87.5%
19:25:30Z 25.017N 86.867W 988.1 mb
(~ 29.18 inHg) 159 meters
(~ 522 feet) 1006.2 mb
(~ 29.71 inHg) - From 253 at 11 knots
(From the WSW at ~ 12.6 mph) 23.0C
(~ 73.4F) 21.5C
(~ 70.7F) 13 knots
(~ 14.9 mph) 10 knots*
(~ 11.5 mph*) 1 mm/hr*
(~ 0.04 in/hr*) 8.5 knots* (~ 9.7 mph*)
76.9%*
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We have a LLC of around 1005mbs and a w and wsw wind... should be Andrea at 5pm if they can locate winds of 35Kts that were reported by ships this morning. 70% chance
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Blogs about to go into hyperdrive.
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403. VR46L
Quoting seminolesfan:

It sure is! LOL

According to our blog overlords it is fighting it off and closing off a new LLC. LOLagain...


Aye I thought it was a dangerous question to ask!

but its what I see!


LOL
Member Since: March 1, 2012 Posts: 0 Comments: 6842
Quoting MiamiHurricanes09:
How about now?

Plenty of W/WSW/WNW winds and a 1006mb pressure.


192230 2457N 08705W 9877 00169 0070 +233 +219 278005 006 010 000 00
192300 2458N 08703W 9877 00168 0069 +232 +220 250007 007 012 000 00
192330 2459N 08701W 9876 00168 0068 +231 +221 249007 008 010 000 00
192400 2459N 08659W 9881 00160 0065 +230 +221 264007 007 011 000 03
192430 2500N 08656W 9878 00161 0063 +230 +218 260007 008 013 000 00
192500 2501N 08654W 9874 00164 0062 +233 +214 249008 008 007 001 00
192530 2501N 08652W 9881 00159 0062 +230 +215 253011 013 010 001 03
Might be td 1 soon.
Member Since: October 15, 2011 Posts: 0 Comments: 4085
401. Skyepony (Mod)
Quoting 7544:
any west winds yet ?

They just found another ssw at 24.783N 87.700W. There was another 10 mins west of there too.
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Pressure holding steady at 1008

Time: 19:15:00Z
Coordinates: 24.8N 87.6333W
Acft. Static Air Press: 987.6 mb (~ 29.16 inHg)
Acft. Geopotential Hgt: 178 meters (~ 584 feet)
Extrap. Sfc. Press: 1008.1 mb (~ 29.77 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 20° at 1 knots (From the NNE at ~ 1.1 mph)
Air Temp: 23.4°C (~ 74.1°F)
Dew Pt: 22.2°C (~ 72.0°F)
Peak (10s) Flt. Lvl. Wind: 2 knots (~ 2.3 mph)
SFMR Peak (10s) Sfc. Wind: 12 knots* (~ 13.8 mph*)
SFMR Rain Rate: 0 mm/hr* (~ 0 in/hr*)
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Looks like some SW wind here on the bay
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Recon finds a 1006 Mb pressure
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How about now?

Plenty of W/WSW/WNW winds and a 1006mb pressure.


192230 2457N 08705W 9877 00169 0070 +233 +219 278005 006 010 000 00
192300 2458N 08703W 9877 00168 0069 +232 +220 250007 007 012 000 00
192330 2459N 08701W 9876 00168 0068 +231 +221 249007 008 010 000 00
192400 2459N 08659W 9881 00160 0065 +230 +221 264007 007 011 000 03
192430 2500N 08656W 9878 00161 0063 +230 +218 260007 008 013 000 00
192500 2501N 08654W 9874 00164 0062 +233 +214 249008 008 007 001 00
192530 2501N 08652W 9881 00159 0062 +230 +215 253011 013 010 001 03
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting VR46L:
Is that dry air I spy Punching right into the system?





It sure is! LOL

According to our blog overlords it is fighting it off and closing off a new LLC. LOLagain...
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Quoting bucyouup68:


Looks like it may be another Debbie, I was out of town in Rhode Island when that came through. We got water over the seawall.


I did too in Fort Myers
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Quoting VR46L:
Is that dry air I spy Punching right into the system?







Doesn't look like it... it's more like a sign that 91L is winding up.
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392. 7544
any west winds yet ?
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I think I just saw a rain drop......Flood Watch in Effect for Entire Tampa Bay Area
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Link

New COC partially exposed to the southwest.

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Quoting GTcooliebai:
Hi Nigel, how's it going buddy?
Quoting Ameister12:

Hey Nigel! How's it going?

I'm good. Thanks for asking!
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Quoting TylerStanfield:
Recon en route to new suspected low. Recon also finding some small vorticies spinning around to the west of the storm.


Especially on the latest recon data, you're right on the vortices west of the center.
Member Since: December 21, 2007 Posts: 13 Comments: 3044
tryin to close off a new coc at 24.36n and 86.16w?
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If I had to guess the new center is around 86W & 26N.

Link
Member Since: May 28, 2013 Posts: 0 Comments: 349
Second old center

Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 5th day of the month at 19:06Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Mission Purpose: Investigate first suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 06

Mandatory Data...

Observation Time: Wednesday, 19:07Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 24.6N 88.2W
Location: 389 miles (626 km) to the SSE (163°) from New Orleans, LA, USA.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 310 meters
Flight Level Wind: 5 knots (~ 5.8 mph) (Bearing was unavailable.)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 21°C
Flight Level Dew Point: 20°C
Weather (within 30 nautical miles): Scattered clouds (trace to 4/8 cloud coverage)
Mean Sea Level Pressure (MSLP): 1008 mb (extrapolated)

Optional Data...

Estimated Surface Wind Direction: Bearing was unavailable.
Estimated Surface Wind Speed: 5 knots (~ 5.8 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 11 knots (~ 12.7mph)
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Quoting TylerStanfield:
Recon en route to new suspected low. Recon also finding some small vorticies spinning around to the west of the storm.

I'm not surprised by the multiple vortices, since 91L's origins were rather monsoonal in nature. It's pretty remarkable how quickly the new center formed and became dominant, though. Normally these types of storms take longer to get a consolidated center.
Member Since: July 7, 2010 Posts: 0 Comments: 5648
383. VR46L
Is that dry air I spy Punching right into the system?




Member Since: March 1, 2012 Posts: 0 Comments: 6842
Getting close to the new center now.

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
19:06:00Z 24.617N 88.267W 976.8 mb
(~ 28.84 inHg) 267 meters
(~ 876 feet) 1007.2 mb
(~ 29.74 inHg) - From 132° at 1 knots
(From the SE at ~ 1.1 mph) 23.7°C
(~ 74.7°F) 22.4°C
(~ 72.3°F) 3 knots
(~ 3.4 mph) 9 knots*
(~ 10.3 mph*) 1 mm/hr*
(~ 0.04 in/hr*) 3.0 knots* (~ 3.4 mph*)
300.0%*
19:06:30Z 24.617N 88.233W 976.7 mb
(~ 28.84 inHg) 272 meters
(~ 892 feet) 1007.5 mb
(~ 29.75 inHg) - From 157° at 4 knots
(From the SSE at ~ 4.6 mph) 23.5°C
(~ 74.3°F) 22.3°C
(~ 72.1°F) 5 knots
(~ 5.8 mph) 9 knots*
(~ 10.3 mph*) 0 mm/hr*
(~ 0 in/hr*) 7.2 knots* (~ 8.3 mph*)
180.0%*
19:07:00Z 24.633N 88.200W 976.8 mb
(~ 28.84 inHg) 275 meters
(~ 902 feet) 1007.8 mb
(~ 29.76 inHg) - From 157° at 4 knots
(From the SSE at ~ 4.6 mph) 23.3°C
(~ 73.9°F) 22.3°C
(~ 72.1°F) 4 knots
(~ 4.6 mph) 12 knots*
(~ 13.8 mph*) 0 mm/hr*
(~ 0 in/hr*) 12.0 knots* (~ 13.8 mph*)
300.0%*
19:07:30Z 24.633N 88.167W 977.0 mb
(~ 28.85 inHg) 273 meters
(~ 896 feet) 1008.0 mb
(~ 29.77 inHg) - From 138° at 5 knots
(From the SE at ~ 5.8 mph) 23.0°C
(~ 73.4°F) 22.4°C
(~ 72.3°F) 6 knots
(~ 6.9 mph) 11 knots*
(~ 12.6 mph*) 0 mm/hr*
(~ 0 in/hr*) 9.2 knots* (~ 10.5 mph*)
183.3%*
19:08:00Z 24.650N 88.133W 976.8 mb
(~ 28.84 inHg) 276 meters
(~ 906 feet) 1008.1 mb
(~ 29.77 inHg) - From 134° at 3 knots
(From the SE at ~ 3.4 mph) 23.2°C
(~ 73.8°F) 22.2°C
(~ 72.0°F) 4 knots
(~ 4.6 mph) 12 knots
(~ 13.8 mph) 0 mm/hr
(~ 0 in/hr) 9.0 knots (~ 10.3 mph)
300.0%
19:08:30Z 24.667N 88.083W 977.1 mb
(~ 28.85 inHg) 273 meters
(~ 896 feet) 1008.1 mb
(~ 29.77 inHg) - From 135° at 5 knots
(From the SE at ~ 5.8 mph) 23.0°C
(~ 73.4°F) 22.3°C
(~ 72.1°F) 5 knots
(~ 5.8 mph) 12 knots
(~ 13.8 mph) 0 mm/hr
(~ 0 in/hr) 12.0 knots (~ 13.8 mph)
240.0%
19:09:00Z 24.667N 88.050W 977.0 mb
(~ 28.85 inHg) 273 meters
(~ 896 feet) 1008.1 mb
(~ 29.77 inHg) - From 126° at 3 knots
(From the SE at ~ 3.4 mph) 23.1°C
(~ 73.6°F) 22.0°C
(~ 71.6°F) 4 knots
(~ 4.6 mph) 11 knots*
(~ 12.6 mph*) 0 mm/hr*
(~ 0 in/hr*) 8.2 knots* (~ 9.5 mph*)
275.0%*
19:09:30Z 24.683N 88.017W 977.3 mb
(~ 28.86 inHg) 271 meters
(~ 889 feet) 1008.1 mb
(~ 29.77 inHg) - From 116° at 6 knots
(From the ESE at ~ 6.9 mph) 23.0°C
(~ 73.4°F) 22.1°C
(~ 71.8°F) 6 knots
(~ 6.9 mph) 12 knots
(~ 13.8 mph) 0 mm/hr
(~ 0 in/hr) 12.0 knots (~ 13.8 mph)
200.0%
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Quoting sar2401:

Good afternoon, Nigel. How's the weather down your way?

It's very windy...we're having a bit of intermittent showers as well.
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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.