Surface trough over the southern GOM

[GCANE]

Some big convection is starting to fire between Jamica and Cuba.
Looks like its associated with a LL trough.
Low shear environment.

Euro, GFS, Icon has LL vort or surface low forming in about 70 hrs.

Stay tuned for updates.

[AJC3]

Some interaction with a developing Central American Gyre (CAG)
pattern will make this an area of interest for at least the next week.
Of course, climo says this the the prime area to start watching in
October, so obviously we'll be watching this area until the end of
the season. No real surprise here.

Since there's already a developing incipient disturbance, we'll need
to keep the discussion focused on that feature, and not have this
be a "end-of-season catch-all" for this area. We'll also probably need
to tweak the thread title eventually to be more specific about any
further development and evolution of any feature in this area.

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
801 PM EDT Fri Sep 27 2019

...SPECIAL FEATURES...

<snip>

...A heavy rain event in Central America and Southeastern Mexico...

Southwesterly monsoonal flow is pushing abundant moisture from
the tropical Pacific Ocean toward Central America. Heavy rainfall
is expected in Central America, through the weekend. The greatest
threat for heavy rainfall will migrate northwestward to areas
from western Nicaragua, southern Honduras, southern Guatemala, to
southern Mexico, including in the Mexican states of Chiapas,
Oaxaca and Guerrero. It is possible that the heavy rains may lead
to flash floods and mudslides, especially in areas of mountainous
terrain and areas near the Pacific coast.

<snip>

CARIBBEAN SEA...

A heavy rainfall event is expected in Central America and
southeastern Mexico this weekend. Please read the Special
Features section above for more details.

A middle level low over the Bahamas extends a trough across Cuba
and the NW Caribbean. This is supporting a surface trough from the
Great Bahama Bank through central Cuba to 19N80W, along with
scattered heavy showers and tstms N of 18N between 75W and 82W.
Similar shower activity is within 90 nm of the northern coast of
Colombia and over central Hispaniola. Otherwise, gentle to
moderate trades are across the basin due to a weak pressure
gradient across the region. Trade winds will increase over much
of the central and western Caribbean through early next week .

[Hurricaneman]

Some interaction with a developing Central American Gyre (CAG)
pattern will make this an area of interest for at least the next week.
Of course, climo says this the the prime area to start watching in
October, so obviously we'll be watching this area until the end of
the season. No real surprise here.

Since there's already a developing incipient disturbance, we'll need
to keep the discussion focused on that feature, and not have this
be a "end-of-season catch-all" for this area. We'll also probably need
to tweak the thread title eventually to be more specific about any
further development and evolution of any feature in this area.

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
801 PM EDT Fri Sep 27 2019

...SPECIAL FEATURES...

<snip>

...A heavy rain event in Central America and Southeastern Mexico...

Southwesterly monsoonal flow is pushing abundant moisture from
the tropical Pacific Ocean toward Central America. Heavy rainfall
is expected in Central America, through the weekend. The greatest
threat for heavy rainfall will migrate northwestward to areas
from western Nicaragua, southern Honduras, southern Guatemala, to
southern Mexico, including in the Mexican states of Chiapas,
Oaxaca and Guerrero. It is possible that the heavy rains may lead
to flash floods and mudslides, especially in areas of mountainous
terrain and areas near the Pacific coast.

<snip>

CARIBBEAN SEA...

A heavy rainfall event is expected in Central America and
southeastern Mexico this weekend. Please read the Special
Features section above for more details.

A middle level low over the Bahamas extends a trough across Cuba
and the NW Caribbean. This is supporting a surface trough from the
Great Bahama Bank through central Cuba to 19N80W, along with
scattered heavy showers and tstms N of 18N between 75W and 82W.
Similar shower activity is within 90 nm of the northern coast of
Colombia and over central Hispaniola. Otherwise, gentle to
moderate trades are across the basin due to a weak pressure
gradient across the region. Trade winds will increase over much
of the central and western Caribbean through early next week .

I’d say even maybe the next few weeks

[GCANE]

Weak to moderate convection currently firing across a weak, extended LL trough

[GCANE]

Large area of 500mb convergent flow.
Weak anti-cyclone overhead.

[GCANE]

Picking up WPAC moisture thru Panama

[GCANE]

Massively high CAPE air flowing into the trough

[GCANE]

[GCANE]

CMC & UKMET have genesis north of Jamacia in 48 to 60 hrs

[NDG]

This might be the reason why the GFS is more enthusiastic about development in the Caribbean on its long range than the Euro is.

[SFLcane]

This might be the reason why the GFS is more enthusiastic about development in the Caribbean on its long range than the Euro is.


https://i.imgur.com/34kT13A.gif

ECMWF is in Phase 1 too. GFS more amplified though which to me is that typical bias.

[Steve]

A believable Canadian solution in the 12z run develops the low pressure into what appears to be depicted as a TS as it heads for the SC TX Coast, moves south along the coast and buries in Mexico due to high pressure pushing down from the north. That’s not a usual track for October, so there’s certainly an outside chance the center dips down into the BoC and comes back up (obviously predicated on the CMC being right with a TS approaching the TX Coast).

[GCANE]

Very favorable CCKW conditions for most of October

[Steve]

CMC still brings a low to the TX coast and drops to the Bay of Campeche. Icon flirts around Cuba and south Florida. Gfs not much.

[GCANE]

Euro seems to be defining the 850mb vort better run to run.
Has it now strengthening it a bit thru the Yucatan Channel into the GOM.

[cycloneye]

 https://twitter.com/MJVentrice/status/1178230952130158592

[GCANE]

UKMET is getting bullish.
Almost all models, including old GFS is latching onto this.
New GFS is the outlier.

[GCANE]

[GCANE]

Looks like this maybe the interaction of a wave currently at 66W and a 500mb trough in the Bahamas.
Wave will of course be moving west.
Trough is forecast to drop to the SW into the west Carib.

[GCANE]

Both are well defined on 500mb.