747
FXCA20 KWBC 181911
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
311 PM EDT FRI OCT 18 2024
FORECAST BULLETIN 18 OCT 2024 AT 1900 UTC:
THE NATIONAL HURRICANE CENTER CONTINUES TO MONITOR TWO AREAS OF
POSSIBLE TROPICAL CYCLONE FORMATION IN THE ATLANTIC BASIN. ONE
SYSTEM IS KNOWN AS AL94...CURRENTLY NEAR 65W...AND THE OTHER IS AN
AREA OF LOW PRESSURE IN THE WESTERN CARIBBEAN JUST NORTHEAST OF
HONDURAS...NOW KNOWN AS AL95. AS OF THIS WRITING...THROUGH 48
HOURS...THE CHANCE OF FORMATION IS 20 PERCENT FOR AL94...AND 70
PERCENT FOR AL95. THE LATEST GUIDANCE CONTINUES TO SUGGEST THAT
THE STRONGEST SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AL94 WILL
BE TO THE NORTH OF THE NORTHEAST CARIBBEAN ISLANDS TODAY INTO
SATURDAY...AND THIS IS ALREADY BEING OBSERVED ON SATELLITE
IMAGERY. THAT SAID...SHOWERS AND THUNDERSTORMS DIRECTLY ASSOCIATED
WITH AL94 COULD AFFECT THE TURKS AND CAICOS AS WELL AS THE
SOUTHERN BAHAMAS FROM SATURDAY INTO SUNDAY. SATELLITE IMAGERY IS
ALSO SHOWING DEEP CONVECTION RELATED TO AL95...AND THE MODEL
GUIDANCE IS STARTING TO BE MORE IN AGREEMENT IN TERMS OF RAINFALL
OVER NORTHERN CENTRAL AMERICA INTO SOUTHERN MEXICO.
ACROSS THE ATLANTIC AND EASTERN TROPICAL REGION...THE TWO SYSTEMS
NHC IS MONITORING ARE TAKING CENTER STAGE ON THE RAINFALL
POTENTIAL OVER THE AREA. HOWEVER...THERE ARE OTHER SYNOPTIC
FEATURES THAT WILL CONTRIBUTE TO THE OVERALL RAINFALL POTENTIAL
OVER THE TROPICAL REGION. THE MONSOON TROUGH IS EXTENDING FROM THE
PACIFIC INTO THE SOUTHERN CARIBBEAN. THERE IS A BROAD HIGH
PRESSURE ACROSS THE EASTERN ATLANTIC. ANOTHER HIGH PRESSURE OVER
THE EASTERN USA THAT IS EXTENDING INTO THE GULF OF MEXICO. A LOW
PRESSURE IN THE WESTERN ATLANTIC...NEAR 37N/67W WITH A FRONTAL
BOUNDARY THAT IS CURRENTLY STATIONARY AND IT EXTENDS FROM THE LOW
PRESSURE SOUTHWEST THROUGH THE BAHAMAS...CUBA..AND INTO THE
YUCATAN PENINSULA. 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
WESTERN ATLANTIC...BUT THE ASSOCIATED TROUGH AND STRONG MID AND
UPPER LEVEL WINDS EXTEND INTO THE GULF OF MEXICO AND THE WESTERN
TROPICAL ATLANTIC. THIS FRONTAL BOUNDARY IS EXPECTED TO REMAIN
STATIONARY FROM EAST OF THE BAHAMAS TO AROUND THE YUCATAN
PENINSULA TODAY...WHILE FURTHER EAST OF THE BAHAMAS...THE FRONTAL
BOUNDARY WILL BECOME A COLD FRONT BY THIS EVENING. BY SATURDAY
EVENING INTO SUNDAY...THE FRONTAL BOUNDARY WILL BECOME A COLD
FRONT FROM THE TROPICAL ATLANTIC WEST INTO NEAR YUCATAN...THEN
STATIONARY IN THE CENTRAL GULF OF MEXICO...AS IT
WEAKENS...FRAGMENTING BY SUNDAY NIGHT INTO MONDAY. SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO BE EXPECTED ALONG THE FRONTAL
BOUNDARY OVER CUBA AND THE BAHAMAS THIS WEEKEND...AS IT INTERACTS
WITH THE MID AND UPPER LEVEL TROUGHS...AS WELL AS ALLOWING FOR
MOISTURE TO POOL JUST AHEAD OF THE FRONTAL BOUNDARY ACROSS THE
TROPICAL ATLANTIC.
IN TERMS OF RAINFALL ACROSS THE REGION...THE MODEL GUIDANCE IS IN
MORE AGREEMENT NOW COMPARED TO THE PAST FEW DAYS...ESPECIALLY WHEN
IT COMES TO THE RAINFALL OVER NORTHERN CENTRAL AMERICA AND
SOUTHERN MEXICO. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AL95
ARE DEVELOPING AROUND THE BROAD CIRCULATION...BUT OVERALL
DISORGANIZED SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED ACROSS
THE TROPICAL REGION THROUGH THE WEEKEND. ONE PARTICULAR AREA TO
NOTE IS AREAS IN AND AROUND CUBA...WHERE THE MODEL GUIDANCE SEEMS
TO BE UNDERESTIMATING THE RAINFALL POTENTIAL OVER THE AREA. THE
LATEST SATELLITE IMAGERY SHOWS MORE CONVECTION THAN THE MODEL
GUIDANCE WOULD HAVE SUGGESTED FOR AREAS NEAR CUBA ALONG THE
FRONTAL BOUNDARY. THIS UNDERESTIMATING OF THE RAINFALL IN THE AREA
HAS BEEN OBSERVED OVER THE PAST FEW DAYS...FOR THAT REASON OUR
RAINFALL FORECAST FOR AREAS IN AND AROUND CUBA IS HIGHER THAN WHAT
THE MODEL GUIDANCE IS SUGGESTING. ACCORDING TO THE LATEST
GUIDANCE...THE COMBINED 3-DAY RAINFALL FORECAST INDICATES THAT THE
AREAS WITH MOST RAINFALL...NOT SURPRISING...WILL BE OVER SECTORS
FROM BELIZE TO PORTIONS OF SOUTHERN MEXICO...PARTICULARLY OVER
OAXACA AND VERACRUZ.
EASTERLY/TROPICAL WAVES INITIALIZED AT 12 UTC
TYPE SOF INT 19/00 19/12 20/00 20/12 21/00 21/12 22/00 22/12
TW 21N 65W 66W 68W 70W 73W 75W 78W 80W 83W
A TROPICAL WAVE IS INITIALIZED AT 65W AND TO THE SOUTH OF 21N.
THIS WAVE IS EXPECTED TO MOVE WEST. MOST OF ITS CONVECTION AND
MOISTURE IS FORECAST TO REMAIN NORTH OF THE GREATER ANTILLES THIS
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 GREATER ANTILLES AND THE CARIBBEAN THIS WEEKEND.
THE NATIONAL HURRICANE CENTER IS MONITORING THIS SYSTEM FOR
TROPICAL CYCLONE FORMATION...CURRENTLY WITH A 20 PERCENT CHANCE OF
FORMATION THROUGH 48 HOURS AND 7 DAYS.
ALAMO...(WPC)
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