Area from NW Caribbean across Cuba to the Bahamas (now INVEST 99L)

[DESTRUCTION5]

The long-range GFS looks to be a case of the GFS being unable to properly handle convection within the monsoon gyre. I'm skeptical of the 12Z solution.

Well either way the 12z GFS certainly kicks FL right in the Peninsula.

[AdamFirst]

Is this thread for the area being highlighted by the NHC now or the area being shown in days 8-10 by the models?

It's for both, apparently, as both threads have been merged. I think the more immediate threat will probably get an invest number soon.

[LarryWx]

Is this thread for the area being highlighted by the NHC now or the area being shown in days 8-10 by the models?

As of now, posters are treating it as being for either one. I think the best way to seperate the two would be to seperate by timeframe. So, maybe call one "the area around FL *this weekend* " or something similar and call the other "western Caribbean *not this weekend or starting in about a week*". The idea would be to have the timeframe in the titles.

[SoupBone]

EC has a large upper trough over most of the Gulf. Southerly shear over the Caribbean system

ok, so there you go. So maybe the hoopla will be for naught.

These threads combined are somewhat confusing, but I think he's only referring to the Caribbean/Florida system, not the Central American Gyre one, right?

[HurricaneBelle]

Is this thread for the area being highlighted by the NHC now or the area being shown in days 8-10 by the models?

As of now, posters are treating it as being for either one. I think the best way to seperate the two would be to seperate by timeframe. So, maybe call one "the area around FL *this weekend* " or something similar and call the other "western Caribbean *not this weekend or starting in about a week*". The idea would be to have the timeframe in the titles.

Since there is no current, actual area of disturbed weather that can be pinpointed to discuss the potential storm shown by the models on Oct 6-8, discussion for it belongs in the Global Models Discussion thread, but for some reason people can help but keep discussing it in this thread even though it's a "modelstorm" for now.

[marionstorm]

Is there a chance of greater than 20mph winds for marion county? Duke Energy can't handle that sort of wind. We'll be out of power for days.

[TheStormExpert]

 https://twitter.com/tropicaltidbits/status/913448066132381697




 https://twitter.com/tropicaltidbits/status/913448876333572098

[jlauderdal]

Is there a chance of greater than 20mph winds for marion county? Duke Energy can't handle that sort of wind. We'll be out of power for days.

yes, you can get 20 mph in afternoon t storms..why cant they handle 20 mph winds?

[SFLcane]

2pm..Now up to 30-50 for development.

[Alyono]

EC has a large upper trough over most of the Gulf. Southerly shear over the Caribbean system

ok, so there you go. So maybe the hoopla will be for naught.

These threads combined are somewhat confusing, but I think he's only referring to the Caribbean/Florida system, not the Central American Gyre one, right?

Central American Gyre

[tropicwatch]

Would think that it would be an Invest soon.

[SouthFloridian92]

What exactly is a gyre?

[wxman57]

https://twitter.com/tropicaltidbits/status/913448066132381697

https://twitter.com/tropicaltidbits/sta ... 6333572098

Levi was tweeting about a completely different system from the disturbance that's now just east of the Keys. It's for the system that forms in the NW Caribbean late next week.

[tolakram]

Is this thread for the area being highlighted by the NHC now or the area being shown in days 8-10 by the models?

As of now, posters are treating it as being for either one. I think the best way to seperate the two would be to seperate by timeframe. So, maybe call one "the area around FL *this weekend* " or something similar and call the other "western Caribbean *not this weekend or starting in about a week*". The idea would be to have the timeframe in the titles.

We don't support model storm threads, so there is no other thread right now. It can be discussed in the global model thread if desired but right now this disturbance is the only one that merits a unique thread.

[chaser1]

What exactly is a gyre?

Most everything that seems to form in the Southwest Caribbean during October or November lol (sorry, a bit of Florida hurricane season humor here). Unlike a specific and relative small to mid sized area of disturbed weather or perhaps an area of distinct low pressure, a "gyre" refers to a very large spiral or vortex. So, this very very large expansive area of lower pressure and broad weak counter clockwise turning often acts as a monsoonal breeding ground that can spin off one or more areas of vorticity (oh, "that" word is gonna start up another word soup discussion here lol) that they themselves can develop into discrete tropical systems and potentially into tropical depressions, storms, etc. On the other hand, these large "gyre's" can themselves eventually develop into large tropical systems themselves. A couple characteristics about these however, they often dump a MASSIVE amount of precip over large areas and that because of their very size, while incredibly large rain machines.... they are way slower to develop into raging major hurricanes. This is because of their large size and the time it takes to consolidate a small tight core with low enough pressures that a significant pressure gradient exists between the core (center or eye) and the breadth of the circulation. It is this very pressure gradient that causes the strong winds and is why it is so much more common to see rapid intensification in smaller storms than in larger ones.

[tolakram]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Sep 28 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Maria, located a few hundred miles east-northeast of Cape
Hatteras, North Carolina, and on Hurricane Lee, located over the
central Atlantic Ocean several hundred miles east of Bermuda.

1. A large area of cloudiness and showers extending from the Cayman
Islands northward across Cuba to the Florida Straits is associated
with a broad surface trough interacting with an upper-level low. A
weak area of low pressure is likely to form from this weather system
while it moves northward across the Florida Straits to near the east
coast of the Florida peninsula during the next few days, and
environmental conditions appear conducive for development before
upper-level winds become less favorable early next week. Regardless
of development, this system is likely to produce locally heavy
rainfall over portions of central and western Cuba, the Florida
Keys, the Florida peninsula, and the northwestern Bahamas during the
next several days.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...50 percent.

Forecaster Stewart

[wxman57]

Here's the place to watch. It's moving east of the Keys now. Good rotation/vorticity. Very high chance of a low-level circulation by late tomorrow or on Saturday. Also very high chance it will be interacting with the cold front moving off the SE U.S. Coast late Saturday/Sunday. Strong high pressure to its north will mean winds near TS strength along the NE coast of Florida and into Georgia from Saturday morning through Sunday morning. I'd say near 100% chance of low formation, maybe 60% chance of 34kt (39 mph) winds. However, it may be only partly tropical in nature. Strong shear and the fact that it will likely be inland by Sunday morning will limit any strengthening.

[fci]

OK, the Euro still has it at 12Z with it forming late Fri near Melbourne, moving NE to ~100 miles E of St. Aug. Sat afternoon, and then coming back SW to Melbourne on Sunday afternoon followed by weakening.

Local Met here in Palm Beach had the same forecast this morning.

[LarryWx]

Here's the place to watch. It's moving east of the Keys now. Good rotation/vorticity. Very high chance of a low-level circulation by late tomorrow or on Saturday. Also very high chance it will be interacting with the cold front moving off the SE U.S. Coast late Saturday/Sunday. Strong high pressure to its north will mean winds near TS strength along the NE coast of Florida and into Georgia from Saturday morning through Sunday morning. I'd say near 100% chance of low formation, maybe 60% chance of 34kt (39 mph) winds. However, it may be only partly tropical in nature. Strong shear and the fact that it will likely be inland by Sunday morning will limit any strengthening.

This is the risk for NE FL/SE GA/SE SC, a very windy period this weekend even if only a realatively weak, subtropical low due to the strong gradient between the low and the strong high to the north. There could certainly be coastal flooding with this setup from CHS south to St. Augustine.

[rickybobby]

Here's the place to watch. It's moving east of the Keys now. Good rotation/vorticity. Very high chance of a low-level circulation by late tomorrow or on Saturday. Also very high chance it will be interacting with the cold front moving off the SE U.S. Coast late Saturday/Sunday. Strong high pressure to its north will mean winds near TS strength along the NE coast of Florida and into Georgia from Saturday morning through Sunday morning. I'd say near 100% chance of low formation, maybe 60% chance of 34kt (39 mph) winds. However, it may be only partly tropical in nature. Strong shear and the fact that it will likely be inland by Sunday morning will limit any strengthening.
http://wxman57.com/images/Disturbance.JPG

Do you think it could be a weak ts?