Wet subtropical storm possible for Florida this weekend

By: Dr. Jeff Masters , 3:29 PM GMT on October 05, 2011

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A large low pressure system with heavy rains is expected to develop over Cuba and South Florida on Saturday. The counter-clockwise flow around this low will bring strong winds and heavy rains to much of the Florida coast on Saturday, and these conditions will spread northwards to Georgia by Sunday and South Carolina by Monday. Most of the models develop this system into a tropical or subtropical storm, but the potential location of such a storm is still murky. The ECMWF model predicts the storm will form in the eastern Gulf of Mexico on Monday, then move north into the Florida Panhandle on Tuesday. If this track verifies, the oil rigs off the coast of Southeast Louisiana may experience a one or two day period of sustained winds above tropical storm force Monday or Tuesday. The GFS and NOGAPS models put the storm on the other side of Florida, over the Northwestern Bahamas, and predict the storm will move northwards and hit North Carolina on Wednesday. The UKMET model is in-between, developing the storm right on top of Florida. Since the storm is going to be getting its start as a cold-cored upper-level low pressure system with some dry air aloft, it will probably start out subtropical, with a large band of heavy rain developing well north of the center, bringing heavy rains to a wide region of the Southeast U.S. Subtropical storms cannot intensify quickly, due to their lack of an organized inner core. If the storm follows the path of the GFS model, it could be similar to Subtropical Storm Four of October 4, 1974. That storm brought 10 - 14 inches of rain to the east coast of Florida and strong onshore winds of 30 - 40 mph that caused beach erosion and coastal flooding. The extended forecast discussion from NOAA's Hydrometeorological Prediction Center has a more technical discussion of this coming storm for those interested.


Figure 1. Rainfall forecast for the 5-day period ending at 8 am EDT Monday, October 10, 2011. The storm system affecting Florida this weekend is expected to bring up to 7 inches of rain along the coast. Image credit: NOAA/HPC.

Tropical Storm Philippe no threat to land
In the middle Atlantic, Tropical Storm Philippe is about to interact with a frontal system and turn northeastward out to sea. Satellite loops show Philippe is a small system with a modest amount heavy thunderstorm activity, with the surface circulation partially exposed to view by wind shear. Wind shear will remain in the moderate range today, which may allow the storm to intensify into a hurricane, as predicted by several of the intensity forecast models. By Thursday, wind shear will rise to a very high 30 - 50 knots, which should cause rapid weakening. Philippe will not trouble any land areas.


Figure 2. Morning satellite image of Tropical Storm Philippe. The band of clouds to the northwest of Philippe is associated with a cold front that is expected to absorb the storm and recurve it to the northeast on Thursday.

Jeff Masters

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Quoting Seflhurricane:
looks likely to me our sub tropical system will form over the bahamas

Yep.
Member Since: July 6, 2010 Posts: 113 Comments: 31537
Quoting TropicalAnalystwx13:

So...

Incorrect and Rude.
looks likely to me our sub tropical system will form over the bahamas
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Quoting arekay:
Wrong, just a new username. Your the idiot if you think the # of posts reflects the persons knowledge.


So...

Incorrect and Rude.
Member Since: July 6, 2010 Posts: 113 Comments: 31537
OT, but...
Steve Jobs is dead!
Anyway Philippe:
Member Since: July 7, 2010 Posts: 0 Comments: 5630
Quoting clwstmchasr:


Turn your TV to CNN
got it , very sad .
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Quoting Seflhurricane:
where did this news come out from . what news outlet


Everywhere. But here's the most official: http://www.apple.com/.
Member Since: November 8, 2009 Posts: 4 Comments: 13466
Quoting TropicalAnalystwx13:
18z GFS at 132 hours:

132 hours out is too far out to mean anything dude.
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Quoting TropicalAnalystwx13:
Off-topic:

Ex-Apple CEO Steve Jobs has died.
where did this news come out from . what news outlet
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True. And sad.

Member Since: November 8, 2009 Posts: 4 Comments: 13466
Quoting TropicalAnalystwx13:
Off-topic:

Ex-Apple CEO Steve Jobs has died.
HUHHHHHHH
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Off-topic:

Ex-Apple CEO Steve Jobs has died.
Member Since: July 6, 2010 Posts: 113 Comments: 31537
Quoting TropicalAnalystwx13:

Incorrect.
by when does it seem the NHC will start to mention a low chance potential area
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Quoting arekay:
I see the usual hype is popping over a non-existent system. These models are worthless unless they are focused in on a developed system and even than they are flaky. I mean common already, the mysterious Caribbean development has been pushed back for the past month now. All these 200-300 hr projections are ridiculous. The only thing that's missing is the comparisons to Wilma.

Incorrect.
Member Since: July 6, 2010 Posts: 113 Comments: 31537
Our little Philippe is chugging along, going, "I think I can, I think I can..."

We believe in you Philippe! Go! Be a hurricane! ;)
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Quoting Drakoen:


That's boring. Here's the graphic you were looking for:

drak looks to me like a cat 2 mmoving across west central florida
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Quoting Thrawst:
Nassau, Bahamas had it's coolest day since Hurricane Irene passed by our area. It only peaked at 84.2 degrees Fahrenheit. It felt great. :)

84F? That is a little too warm for me :P
Member Since: July 6, 2010 Posts: 113 Comments: 31537
I need information for my learning.
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Why is this blog so dead now?
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October could be very interesting for Florida.
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Nassau, Bahamas had it's coolest day since Hurricane Irene passed by our area. It only peaked at 84.2 degrees Fahrenheit. It felt great. :)
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WHY
Member Since: July 7, 2010 Posts: 0 Comments: 5630
Member Since: July 7, 2010 Posts: 0 Comments: 5630
Quoting Drakoen:


That's boring. Here's the graphic you were looking for:



DOOM.

lol.
Member Since: July 6, 2010 Posts: 113 Comments: 31537
Quoting TropicalAnalystwx13:
"Sean" develops in the southwestern Caribbean, moves WNW across the Yucatan peninsula, into the Gulf of Mexico, and curves east into Florida as a strong hurricane...Crosses the state, and stalls off the SE coast.



That's boring. Here's the graphic you were looking for:

Member Since: October 28, 2006 Posts: 57 Comments: 29927
18Z GFS full loop:

Link
Member Since: July 6, 2010 Posts: 113 Comments: 31537
"Sean" develops in the southwestern Caribbean, moves WNW across the Yucatan peninsula, into the Gulf of Mexico, and curves east into Florida as a strong hurricane...Crosses the state, and stalls off the SE coast.

Member Since: July 6, 2010 Posts: 113 Comments: 31537
if its subtropical it will usually have a wider wind field also
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Quoting scott39:
If this potiential system developes off the E coast of Fl......wont most of the rain be offshore?


Not necessarily because most subtropical lows start broad, and it will have to develop within a large-scale easterly flow directed into Florida, which is sure to pile heavy rain into the area regardless.
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Quoting will40:
GFS brings a second system across Fla from west to East
looks like a hurricane or major on that run 982mb. pretty strong storm
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GFS brings a second system across Fla from west to East
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Quoting Levi32:


Sometimes it's hard to pull that off if it's a very open upper trough instead of a cut-off closed upper low. That subtropical invest last year at the beginning of the season was an example of a low pressure area following the divergent region on the eastern side of the trough instead of moving underneath of it.
If this potiential system developes off the E coast of Fl......wont most of the rain be offshore?
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Quoting rmbjoe1954:


Hi Allan:

I hope is well. So what is your take? You think it will reach you on LI?


I think whatever happens, will be either remnants or extratropical if it gets up there.
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Quoting TropicalAnalystwx13:
Levi, I think the Caribbean system is beginning to get pushed back again XD

This is the 18Z GFS at 288 hours:



This subtropical entity is exactly what I have been talking about developing south of the high in the northwest Caribbean, southern gulf, or Bahamas area, exactly as I've been mentioning. It is in an early stage where the subtropical jet is too far south to allow it to be fully tropical in nature, at least to start out with. I noted that multiple systems are possible in this pattern, and so a more truly tropical system out of the deep Caribbean may be on the table later as well.
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Levi, I think the Caribbean system is beginning to get pushed back again XD

This is the 18Z GFS at 288 hours:

Member Since: July 6, 2010 Posts: 113 Comments: 31537
Quoting Levi32:


Sometimes it's hard to pull that off if it's a very open upper trough instead of a cut-off closed upper low. That subtropical invest last year at the beginning of the season was an example of a low pressure area following the divergent region on the eastern side of the trough instead of moving underneath of it.
levi i noticed on the 12z run of the GFS it showed after the subtropical cyclones leaves that true carribean mischeif will start to get going and the model has a storm moving very slowly there and getting strong fast. this scenario possible? thanks :)
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GOES-13 Gulf and Tropics (Updated every ~1/2 hour)
Low Cloud Image and Loop

..click Image for Loop

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Quoting Drakoen:


Oh? You don't think the low could get stacked underneath the trough...hence subtropical?


Sometimes it's hard to pull that off if it's a very open upper trough instead of a cut-off closed upper low. That subtropical invest last year at the beginning of the season was an example of a low pressure area following the divergent region on the eastern side of the trough instead of moving underneath of it.
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Quoting reedzone:


It could, but I can see this on the East Coast more then getting in the GOM. The trough is expected to be located east of Florida, typically, a low should form on the eastern edge of the trough axis.


Oh? You don't think the low could get stacked underneath the trough...hence subtropical?
Member Since: October 28, 2006 Posts: 57 Comments: 29927
Quoting reedzone:


It could, but I can see this on the East Coast more then getting in the GOM. The trough is expected to be located east of Florida, typically, a low should form on the eastern edge of the trough axis.


Hi Allan:

I hope is well. So what is your take? You think it will reach you on LI?
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Quoting TropicalAnalystwx13:

I agree, the T#'s are messed up, lol.


Yep, they kinda are.

Final T# Adj T# Raw T#
2.8 2.8 2.8
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Quoting scott39:
So you dont think it could go in the E GOM?


It could, but I can see this on the East Coast more then getting in the GOM. The trough is expected to be located east of Florida, typically, a low should form on the eastern edge of the trough axis.
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It will be interesting if the models pan out. They seem to be pretty consistant with an East Coast of Fl. system.
But we're also talking 5 days out. So there could be a slight shift to the East or West.
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Quoting Sfloridacat5:
Latest GFS shows the system forming along the East Coast and finally gets going just off the Daytona Beach area.



just about an exact copy of 18z run yesterday
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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.