[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 171434
TCDAT2

Potential Tropical Cyclone Twenty-Two Discussion Number   4
NWS National Hurricane Center Miami FL       AL222023
1000 AM EST Fri Nov 17 2023

First-light visible satellite images indicate that the disturbance
is still a surface trough of low pressure with nearly all of the
deep convection to the east of the trough axis streaming northward
across Jamaica, Haiti, and eastern Cuba.  Surface pressures remain
low--about 1004 mb--but the center of circulation is ill defined.
Maximum winds are still estimated to be 30 kt, primarily within the
deep convection.

The system appears to be accelerating northeastward with an initial
motion of 045/12 kt.  A continued northeastward acceleration is
anticipated during the next day or two as the disturbance moves
ahead of a mid-level trough moving across Florida and the far
northwestern Caribbean Sea.  With the circulation being so broad,
however, global model wind fields suggest the system may jump
discontinuously rather than move seamlessly across the Greater
Antilles during the next 24 hours.  The NHC track forecast favors
the faster model solutions and is generally a blend of the previous
forecast with the latest GFS solution.

The prospects for the disturbance to become a tropical cyclone
appear to be decreasing.  The system is already battling strong
southwesterly shear and mid-level dry air, and none of the global
models any longer depicts the development of a well-defined
circulation.  The new NHC forecast therefore keeps the system as a
disturbance through tonight, with some possibility (albeit
decreasing) of the system becoming a tropical depression or
tropical storm after it passes the mountainous terrain of Jamaica
and southeastern Cuba.  In whatever form the system emerges over
the western Atlantic over the weekend, it is likely to become
extratropical or merge with a front over the weekend.

Despite the decreasing chance of tropical cyclone formation, there
is high confidence that heavy rainfall and flooding will remain a
distinct and serious threat across Jamaica, southeastern Cuba, and
Hispaniola.  Additional rainfall amounts of 4 to 8 inches, with
isolated areas as high as 16 inches, are forecast in these areas
and are likely to produce life-threatening flash flooding and
mudslides.


KEY MESSAGES:

1.  Potential Tropical Cyclone Twenty-Two could produce tropical
storm conditions, especially in areas of heavy rainfall, across
Jamaica, southeastern Cuba, Haiti, the southeastern Bahamas, and the
Turks and Caicos Islands through Saturday, and tropical storm
watches are in effect for these areas.

2.  Heavy rains will impact portions of Jamaica, southeastern Cuba,
and southern Hispaniola through Sunday.  This rainfall is likely to
produce flash flooding, along with mudslides in areas of higher
terrain.  Lighter amounts across the southeastern Bahamas as well
as the Turks and Caicos Islands may lead to flash flooding in urban
areas.


FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 17.5N  79.1W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  18/0000Z 19.3N  76.8W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 24H  18/1200Z 21.9N  73.3W   35 KT  40 MPH...TROPICAL STORM
 36H  19/0000Z 25.2N  68.9W   35 KT  40 MPH
 48H  19/1200Z 28.3N  64.8W   40 KT  45 MPH...POST-TROP/EXTRATROP
 60H  20/0000Z 31.8N  61.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  20/1200Z...ABSORBED BY A FRONT

$$
Forecaster Berg
This weather bulletin was brought to you by:
www.nashvilleweather.net