####018003677####
WTNT42 KNHC 172051

TCDAT2

 

Potential Tropical Cyclone Twenty-Two Discussion Number   5

NWS National Hurricane Center Miami FL       AL222023

400 PM EST Fri Nov 17 2023

 

The disturbance continues to have a broad and elongated circulation 

with a vorticity maximum in the vicinity of western Jamaica and all 

of the associated deep convection east of the trough axis.  Earlier 

ASCAT passes differed on the strength of the system's winds, with 

the B instrument showing 35-40 kt within the Jamaica Channel and the 

C instrument only showing 25-30 kt.  The intensity remains 30 kt 

based on a blend of these data.



The system is accelerating northeastward with an initial motion of 

050/15 kt.  An additional acceleration toward the northeast--close 

to 30 kt by 36-48 hours--is expected as the disturbance gets picked 

up by a shortwave trough moving across Florida toward the 

southwestern Atlantic.  The updated NHC forecast remains near the 

fastest model solutions, and is generally a blend of the previous 

forecast with the latest GFS model.  As noted earlier, the 

disturbance's motion across the Greater Antilles is likely to be 

discontinuous.



The chance for the system to become a tropical cyclone continues to 

decrease and in fact now appears unlikely due to a combination of 

the system's broad structure, the terrain of the Greater Antilles, 

strong southwesterly shear, and mid-level dry air.  However, with 

the strongest surface winds near or just below 35 kt, there is 

still some chance that the system could produce 

tropical-storm-force winds over areas within the tropical storm 

watch, especially within heavy rainfall.  The NHC forecast still 

shows the possibility, albeit small, for the system to become a 

tropical storm in 24-36 hours mainly based on continuity.  After 

that, the system should become extratropical by 48 hours and 

absorbed by a front by 60 hours.  Advisories on this system could be

discontinued at any time if there is no longer a risk of 

tropical-storm-force winds within the tropical storm watch areas.

 

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

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, southeast 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  17/2100Z 18.7N  77.7W   30 KT  35 MPH...POTENTIAL TROP CYCLONE

 12H  18/0600Z 20.7N  75.3W   30 KT  35 MPH...POTENTIAL TROP CYCLONE

 24H  18/1800Z 23.4N  71.3W   35 KT  40 MPH...TROPICAL STORM

 36H  19/0600Z 26.5N  66.0W   35 KT  40 MPH

 48H  19/1800Z 30.1N  60.8W   35 KT  40 MPH...POST-TROP/EXTRATROP

 60H  20/0600Z...ABSORBED BY A FRONT

 

$$

Forecaster Berg