699
FXCA20 KWBC 171932
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
332 PM EDT THU OCT 17 2024
FORECAST BULLETIN 17 OCT 2024 AT 1930 UTC:
THE NATIONAL HURRICANE CENTER IS MONITORING TWO AREAS OF POSSIBLE
TROPICAL CYCLONE FORMATION IN THE ATLANTIC BASIN. ONE SYSTEM IS
KNOWN AS AL94...CURRENTLY NEAR 55W...AND THE OTHER IS AN AREA OF
LOW PRESSURE IN THE WESTERN CARIBBEAN. AS OF THIS
WRITING...THROUGH 7 DAYS...THE CHANCE OF FORMATION ARE 30 PERCENT
FOR AL94...AND ALSO 30 PERCENT FOR THE AREA OF LOW PRESSURE IN THE
WESTERN CARIBBEAN. THE LATEST GUIDANCE SUGGESTS THAT THE STRONGEST
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AL94 WILL BE TO THE
NORTH OF THE NORTHEAST CARIBBEAN ISLANDS FRIDAY INTO
SATURDAY...BUT COULD AFFECT THE TURKS AND CAICOS AS WELL AS THE
SOUTHERN BAHAMAS FROM SATURDAY INTO SUNDAY. THE SYSTEM IN THE
WESTERN CARIBBEAN COULD PRODUCE SIGNIFICANT RAIN OVER PORTIONS OF
NORTHERN CENTRAL AMERICA AND SOUTHERN MEXICO ON FRIDAY THROUGH THE
WEEKEND.
ACROSS THE ATLANTIC AND EASTERN TROPICAL REGION...OTHER THAN THE
TWO SYSTEMS TO MONITOR FOR POSSIBLE TROPICAL CYCLONE FORMATION AND
ITS RAINFALL IMPACTS OVER LAND AREAS...THERE IS A BROAD HIGH
PRESSURE ACROSS THE EASTERN ATLANTIC...AS WELL AS A LOW PRESSURE
IN THE WESTERN ATLANTIC...NEAR 37N/69W. ANOTHER HIGH PRESSURE OVER
THE EAST CENTRAL USA THAT IS EXTENDING INTO THE GULF OF MEXICO.
THE MONSOON TROUGH IS EXTENDING FROM THE PACIFIC INTO IN THE
SOUTHERN CARIBBEAN...WHICH COMBINED WITH THE BROAD LOW PRESSURE IN
THE CARIBBEAN...IS CURRENTLY CAUSING SHOWERS AND THUNDERSTORMS
ACROSS PORTIONS OF CENTRAL AMERICA AND THE CARIBBEAN SEA. THERE IS
ALSO A COLD FRONT THAT IS EXTENDING FROM THE AFOREMENTIONED LOW
PRESSURE OVER THE WESTERN ATLANTIC...SOUTHWEST INTO THE
BAHAMAS...THEN THE FRONTAL BOUNDARY IS STATIONARY AS IT EXTENDS
FROM THE BAHAMAS INTO THE SOUTHERN GULF OF MEXICO. SATELLITE
IMAGERY IS CURRENTLY INDICATING CONVECTION OCCURRING ALONG THE
FRONTAL BOUNDARY...WHICH IS BEING ENHANCED BY BROAD MID AND UPPER
LEVEL LOWS CENTERED OVER THE EASTERN US...BUT THE ASSOCIATED
TROUGH AND STRONG MID AND UPPER LEVEL WINDS EXTEND SOUTH INTO THE
GULF OF MEXICO AND THE WESTERN TROPICAL ATLANTIC. THIS FRONTAL
BOUNDARY IS EXPECTED TO REMAIN STATIONARY FROM THE BAHAMAS TO
AROUND THE YUCATAN PENINSULA TODAY AND FRIDAY...WHILE THE COLD
FRONT WILL CONTINUE TO THE EAST OF THE BAHAMAS. HOWEVER...BY
SATURDAY INTO SUNDAY...A PORTION OF THE FRONTAL BOUNDARY FROM THE
BAHAMAS INTO THE EASTERN GULF OF MEXICO WILL TRANSITION TO A COLD
FRONT AND WILL START TO DRIFT SOUTH INTO NORTHERN CUBA AND ALONG
THE SOUTHERN BAHAMAS...BUT REMAINING STATIONARY OVER THE CENTRAL
GULF OF MEXICO. SHOWERS AND THUNDERSTORMS WILL BE EXPECTED ALONG
THE FRONTAL BOUNDARY OVER CUBA AND THE BAHAMAS FOR THE REST OF THE
WEEK...AS IT INTERACTS WITH THE MID AND UPPER LEVEL TROUGHS...AS
WELL AS ALLOWING FOR MOISTURE TO POOL JUST AHEAD OF THE FRONTAL
BOUNDARY.
IN TERMS OF RAINFALL ACROSS THE REGION...THE MODELS CONTINUE WITH
SOME DISAGREEMENTS...BUT COMPARING THE MODEL GUIDANCE AND HOW IT
IS INITIALIZING WITH THE CURRENT OBSERVATIONS...THE GFS MODEL
SEEMS TO BE CAPTURING THE DEEPER CONVECTION A BIT BETTER...THOUGH
THE OVERALL RAINFALL COVERAGE IS BEST BEING CAPTURED BY OTHER
MODELS. UNSETTLED AND DISORGANIZED SHOWER AND THUNDERSTORM
ACTIVITY IS EXPECTED ACROSS THE TROPICAL REGION OVER THE NEXT FEW
DAYS...WITH THE EXCEPTION OF THE THUNDERSTORM ACTIVITY THAT IS
EXPECTED TO AFFECT NORTH CENTRAL AMERICA INTO SOUTHERN
MEXICO...WHICH IS FORECAST TO BE IN A LARGE CLUSTER OF
THUNDERSTORM ACTIVITY MOVING IN...THOUGH THE GFS SHOWS MUCH MORE
ORGANIZATION OF THESE THAN THE ECMWF MODEL. THAT BEING SAID...DUE
TO THE LOCALIZED CONVECTION EXPECTED ACROSS DIFFERENT SECTIONS OF
THE TROPICS...EACH DAY FROM TODAY THROUGH SUNDAY
MORNING...DIFFERENT AREAS OF THE TROPICAL REGION WILL HAVE MAX
DAILY AMOUNTS REACHING 50MM OR HIGHER. ACCORDING TO THE LATEST
GUIDANCE...THE COMBINED 3-DAY RAINFALL FORECAST INDICATES THAT THE
AREAS WITH MOST CUMULATIVE RAIN WILL BE SOME SECTORS OF CENTRAL
AMERICA FROM BELIZE TO PORTIONS OF SOUTHERN MEXICO. THAT BEING
SAID...OUR FORECAST WENT ABOVE THE MODEL RAINFALL SOLUTIONS FOR A
FEW SECTORS OF CUBA AND THE BAHAMAS DUE TO THE PROXIMITY TO THE
FRONTAL BOUNDARY AND INTERACTING WITH THE MID AND UPPER
LEVELS...ESPECIALLY FOR CUBA WHERE IT COULD ALSO INTERACT WITH THE
LOCAL TERRAIN EFFECTS.
EASTERLY/TROPICAL WAVES INITIALIZED AT 12 UTC
TYPE SOF INT 18/00 18/12 19/00 19/12 20/00 20/12 21/00 21/12
TW 21N 55W 58W 62W 66W 68W 71W 73W 75W 76W
A TROPICAL WAVE IS INITIALIZED AT 55W AND TO THE SOUTH OF 21N.
THIS WAVE IS EXPECTED TO MOVE WEST NORTHWEST. MOST OF ITS
CONVECTION AND MOISTURE IS FORECAST TO MOVE NORTH OF THE
NORTHEASTERN CARIBBEAN ISLANDS BY THE WEEKEND. HOWEVER...THE WAVE
AXIS WILL MOVE THROUGH THE CARIBBEAN OVER THE NEXT FEW DAYS...AND
WILL HAVE A BAND OF DEEPER MOISTURE MOVE THROUGH THE LEEWARDS AND
INTO THE GREATER ANTILLES THIS WEEKEND. THE NATIONAL HURRICANE
CENTER IS MONITORING THIS SYSTEM FOR TROPICAL CYCLONE
FORMATION...CURRENTLY WITH A 30 PERCENT CHANCE OF FORMATION
THROUGH 7 DAYS.
ALAMO...(WPC)
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