ATL: GAMMA - Post-Tropical - Discussion

[aspen]

If the latest model runs play out, 91L might only hit the tip of the Yucatán Peninsula, lessening land impact as the system attempts to organize. However, the situation seems so complex that it’s best to nowcast and not look at the models until we have a defined TC.

[MarioProtVI]

Latest GFS run takes 91L around the Yucatan into the BoC where it spins up to a hurricane before landfall in Veracruz. That area of the Yucatan is notorious for tightening up circulations going into the BoC...Karl 2010, Franklin 2017...even Cristobal as it formed earlier in the year.

[cycloneye]

A well-defined tropical wave located over the western Caribbean Sea
is producing a large area of disorganized showers and thunderstorms.
Conditions are expected to be conducive for a tropical depression
to form by early next week, but only if the system moves and
remains over the waters of the northwestern Caribbean Sea or
southern Gulf of Mexico. Development will become less likely if the
system moves over the Yucatan Peninsula or northern Central America.
Regardless of development, this system is expected to produce
locally heavy rains, with possible flash flooding, over portions of
southeastern Mexico, Central America, and western Cuba during the
next several days, and interests in those areas should monitor the
progress of the disturbance.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

[wxman57]

If the latest model runs play out, 91L might only hit the tip of the Yucatán Peninsula, lessening land impact as the system attempts to organize. However, the situation seems so complex that it’s best to nowcast and not look at the models until we have a defined TC.

Wish we had the luxury of not making a forecast until we're 100% confident where it's going. Will be starting a 7-day forecast by tomorrow morning. Models trending toward something similar to Stan of 2005. Crossing the northern Yucatan this weekend then tracking SW across BoC seems most likely. Tremendous amount of shear and dry air across northern Gulf. Not looking like a northern Gulf threat and most likely not tracking NE to Florida. Pretty sure we'll have Gamma by late this weekend.

[MarioProtVI]

A well-defined tropical wave located over the western Caribbean Sea
is producing a large area of disorganized showers and thunderstorms.
Conditions are expected to be conducive for a tropical depression
to form by early next week, but only if the system moves and
remains over the waters of the northwestern Caribbean Sea or
southern Gulf of Mexico. Development will become less likely if the
system moves over the Yucatan Peninsula or northern Central America.
Regardless of development, this system is expected to produce
locally heavy rains, with possible flash flooding, over portions of
southeastern Mexico, Central America, and western Cuba during the
next several days, and interests in those areas should monitor the
progress of the disturbance.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

I am not really buying the NHC saying Yucatan actually preventing this from forming. We’ve seen several storms in the past actually get organized or develop as it travels over this area.

[eastcoastFL]

Nor much shear in its current location. A good bit ahead of it In the gulf but who knows what the status will be when it gets there.

[Miami Storm Tracker]

Is high pressure that strong that is steers this that far west? With the cool front draped across Florida you would think a ENE or NE direction would be there. Our local weather forecast is for 4 to 6 inches of rain. That will not happen if this get pushed further west.

[gatorcane]

and the NHC finally committed to the Yucatan instead of just moving over the NW Caribbean Sea. Global models suggested this for days now (well except the GFS-P which took more time to come on board with that idea but we know it needs some fixing). Global models so far have handled this one well.

[robbielyn]

Is high pressure that strong that is steers this that far west? With the cool front draped across Florida you would think a ENE or NE direction would be there. Our local weather forecast is for 4 to 6 inches of rain. That will not happen if this get pushed further west.

A second cold front will prevent it from coming this way it will be blocked and hang out in the bay of campache.

[psyclone]

Is high pressure that strong that is steers this that far west? With the cool front draped across Florida you would think a ENE or NE direction would be there. Our local weather forecast is for 4 to 6 inches of rain. That will not happen if this get pushed further west.

The heavy rain over south florida is going to happen with or without a tc. The frontal boundary will do the trick. This system is likely headed westward but plenty of water will be falling regardless


https://www.wpc.ncep.noaa.gov/threats/threats.php

[jlauderdal]

Is high pressure that strong that is steers this that far west? With the cool front draped across Florida you would think a ENE or NE direction would be there. Our local weather forecast is for 4 to 6 inches of rain. That will not happen if this get pushed further west.

THere is a flash flood watch through Sunday night...whenw as the last time you saw one issued for 72h...the stalled front is responsible, not the tropics although some moisture and energy may make it from the current system but really it will have minmail effect.

[Miami Storm Tracker]

So storm or no storm, my boating weekend in the keys is a wash out.

[jlauderdal]

So storm or no storm, my boating weekend in the keys is a wash out.

not necessarily, nobody said it was going to rain all day, everyday..pick your spots

[wxman57]

I am not really buying the NHC saying Yucatan actually preventing this from forming. We’ve seen several storms in the past actually get organized or develop as it travels over this area.

The NHC folks are implying that it may not move back offshore into the BoC in that discussion. If it moves into the BoC, then it will very likely develop.

[cycloneye]

 https://twitter.com/pppapin/status/1311749191543160837

[Nimbus]

North coast of Honduras may close off and tighten a Low level circulation.
Low level clouds are almost stationary right along the coast currently.

[Blinhart]

Our local met on KLFY TV 10 in Lafayette, La., stated that some models are showing this getting into the Southern Gulf and sit there for a week to 3 weeks, due to all the cold fronts coming down and keeping it from moving anywhere.

[SoupBone]

Our local met on KLFY TV 10 in Lafayette, La., stated that some models are showing this getting into the Southern Gulf and sit there for a week to 3 weeks, due to all the cold fronts coming down and keeping it from moving anywhere.

A buddy of mine sent me the Euro ensembles and according to him showed a bunch of different solutions, ranging from Southern Mexico to the Florida Panhandle, with additional potential landfalls in Texas and Louisiana for good measure. I'm not saying it can't happen, but if fronts keep coming down, at some point it has to get lifted out.

[Hypercane_Kyle]

Seems to me that if the LLC develops along the northern edge of the convective envelope, it may just be able to thread the needle between the Yucatan and Cuba.

[gatorcane]

18Z GFS stronger and buries in the BOC. Odd pattern as the storm gets north of the Yucatan and still goes SW: