070
FXCA20 KWBC 271853
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 PM EDT WED SEP 27 2023
FORECAST BULLETIN 27 SEP 2023 AT 1830 UTC: THE NATIONAL HURRICANE
CENTER IS MONITORING A COUPLE OF SYSTEMS IN THE ATLANTIC
BASIN...TROPICAL STORM PHILIPPE AND A BROAD AREA OF LOW PRESSURE
THAT HAS BEEN NAMED AL91. AL91...CURRENTLY ALONG 44W IS MOVING
INTO FAVORABLE ENVIRONMENT FOR DEVELOPMENT...AND THE NATIONAL
HURRICANE CENTER IS SUGGESTING A 90 PERCENT CHANCE OF TROPICAL
CYCLONE FORMATION IN THE NEXT 48 HOURS...AND ALSO A 90 PERCENT
CHANCE OF FORMATION THROUGH 7 DAYS. THE NATIONAL HURRICANE CENTER
EXPECTS THAT A TROPICAL DEPRESSION COULD DEVELOP IN THE NEXT DAY
OR SO. THE LATEST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL REMAIN
TO THE EAST OF THE LESSER ANTILLES...BUT WE WILL MONITOR THE
LATEST FORECAST BY THE NATIONAL HURRICANE CENTER. TROPICAL STORM
PHILIPPE CONTINUES TO STRUGGLE UNDER A SHEARED ENVIRONMENT AS IT
CONTINUES TO MOVE WEST. BASED ON THE LATEST FORECAST BY THE
NATIONAL HURRICANE CENTER...PHILIPPE WILL REMAIN TO THE NORTHEAST
OF THE LEEWARDS THROUGH THE REST OF THE WORKWEEK...BUT THE CENTER
IS NOW FORECAST TO REACH THE NORTHERN LEEWARDS ON SATURDAY
MORNING. PHILIPPE IS WEAKENING...AND THE FORECAST HAS PHILIPPE
BECOMING A REMNANT LOW BY SUNDAY AS IT APPROACHES PR/USVI.
THERE IS A SURFACE HIGH PRESSURE ACROSS THE EASTERN
ATLANTIC...WHICH WILL PREVAIL THROUGH THURSDAY. THEN THERE IS
ANOTHER SFC HIGH PRESSURE EXITING THE NE COAST OF THE US THAT WILL
MOVE INTO THE NW ATLANTIC. A TROUGH ACROSS THE SOUTHWESTERN GULF
OF MEXICO...INTO THE YUCATAN PENINSULA...IS EXPECTED TO PREVAIL
OVER THE AREA FOR THE NEXT FEW DAYS. THERE IS ALSO A TROPICAL WAVE
ALONG 88W BRINGING MOISTURE AND SHOWER ACTIVITY TO PORTIONS OF
CENTRAL AMERICA.
IN THE MID LEVELS...A BROAD HIGH PRESSURE IN THE ATLANTIC...WITH
ITS CENTER TO THE NORTH OF THE GREATER ANTILLES. A MID LEVEL
TROUGH OVER THE YUCATAN PENINSULA IS HELPING THE INSTABILITY AND
THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS TODAY. THERE IS AN
UPPER LEVEL LOW ACROSS THE SOUTHERN CARIBBEAN INTO THE NORTH
PORTION OF SOUTH AMERICA...WHICH WILL HELP IN THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS ACROSS VENEZUELA AND COLOMBIA ON
THURSDAY INTO FRIDAY.
IN MEXICO...THE YUCATAN PENINSULA AND SOUTHERN MEXICO ARE STILL
EXPECTED TO OBSERVE RAINFALL EACH DAY OVER THE 3-DAY FORECAST
PERIOD...DUE TO THE SURFACE TROUGH...AVAILABLE MOISTURE AND
STRONGER WINDS ALOFT. THURSDAY AND FRIDAY IS FORECAST TO BE THE
WETTEST PERIOD ACROSS THE AREA...WHILE A TROPICAL WAVE ALSO MOVES
INTO THAT AREA. THE WEST COAST OF OF MEXICO IS EXPECTED TO OBSERVE
SHOWERS AND THUNDERSTORMS EACH DAY FOR THE REST OF THE
WORKWEEK...THOUGH GENERALLY IN THE ORDER OF 05-10MM/DAY WITH MAX
UP TO 25MM. EAST CENTRAL TO NORTHEAST FROM VERACRUZ TO TAMAULIPAS
IS FORECAST TO OBSERVE RAIN EACH DAY FOR THE REST OF THE
WORKWEEK...BUT MAX TOTALS ARE ALSO TO BE MAINLY IN THE RANGE OF
10-20MM.
IN THE CARIBBEAN...MOSTLY EASTERLY TRADE WINDS WILL PREVAIL OVER
THE AREA.IN TERMS OF RAINFALL...MOST OF THE RAINFALL ACROSS THE
LESSER ANTILLES IS EXPECTED TO BE DUE TO BRIEF SHOWERS. LOCALLY
INDUCED SHOWERS AND THUNDERSTORMS COULD AFFECT ISOLATED AREAS OF
PR AND HISPANIOLA IN THE AFTERNOON HOURS EACH DAY...WHICH COULD
AMOUNT TO OVER 25MM....THOUGH THIS WOULD BE ACROSS VERY ISOLATED
AREAS. OTHERWISE...BRIEF TRADE WIND SHOWERS WOULD AFFECT THE
WINDWARD SIDE OF THE GREATER ANTILLES. RAINFALL TOTALS OF UP TO
10MM WOULD BE GENERALLY EXPECTED ACROSS HISPANIOLA...PUERTO RICO
AND USVI EACH DAY FOR THE REST OF THE WEEK...WITH THE EXCEPTION OF
THE VERY ISOLATED AREAS THAT WERE MENTIONED. 10-15MM IS POSSIBLE
ACROSS THE LESSER ANTILLES EACH DAY FOR THE REST OF THE WORKWEEK.
IN CENTRAL AMERICA...THE DEEP MOISTURE THAT IS AVAILABLE WILL HELP
IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH FRIDAY.
HOWEVER...THE MODEL GUIDANCE HAS REALLY BACKED OFF IN THE AMOUNTS
OF RAIN COMPARED TO YESTERDAY. ALL AREAS OF CENTRAL AMERICA IS
FORECAST TO HAVE SOME RAIN...WITH THE MAX TOTALS RANGING BETWEEN
15 AND 35MM. THAT SAID...PORTIONS OF GUATEMALA AND WESTERN EL
SALVADOR COULD HAVE AS MUCH AS 40-80MM ON THURSDAY INTO FRIDAY AS
THE TROPICAL WAVE REACHES THE AREA.
IN NORTHERN SOUTH AMERICA...THE MODELS HAVE ALSO DECREASED THEIR
RAINFALL SOLUTION CONSIDERABLY WITH THE LATEST MODEL RUNS. WESTERN
COLOMBIA INTO WESTERN ECUADOR ARE THE AREAS WITH THE MOST
SIGNIFICANT RAINFALL WITH TOTALS UP TO AROUND 50 TO 60MM EXPECTED
EACH DAY THROUGH FRIDAY. THE REST OF COLOMBIA AND MOST OF
VENEZUELA IS EXPECTED TO OBSERVE RAINFALL EACH DAY BUT IN THE
ORDER OF 05-10MM/DAY WITH MAX VALUES OF 15-25MM FOR THE MOST PART.
THAT SAID...A TUTT COULD CAUSE SIGNIFICANT SHOWER AND THUNDERSTORM
ACTIVITY ACROSS VENEZUELA AND COLOMBIA ON THURSDAY INTO
FRIDAY...WHERE MAX TOTALS OF 25-50MM ARE FORECAST. NORTHERN PERU
AND EASTERN ECUADOR IS FORECAST TO OBSERVE GENERALLY 05-10MM AND
UP TO 20MM EACH DAY. THE GUIANAS ARE FORECAST TO OBSERVE MINIMAL
RAINFALL EACH DAY...IF ANY. ONLY NORTHWEST GUYANA MAY HAVE
RELIABLE DAILY RAINFALL FOR THE REST OF THE WEEK...WITH MAX TOTALS
IN THE 15-20MM RANGE.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 28/00 28/12 29/00 29/12 30/00 30/12 01/00 01/12
TW 19N 86W 88W 90W 92W 94W 95W 96W 97W 98W
A TROPICAL WAVE IS INITIALIZED AT 86W AND TO THE SOUTH OF 19N. IT
HAS ABUNDANT MOISTURE ASSOCIATED WITH IT AND IT IS OVER CENTRAL
AMERICA. THE TROPICAL WAVE IS FORECAST TO CONTINUE MOVING WEST BUT
DECREASING ITS FORWARD SPEED OVER THE NEXT FEW DAYS. THIS TROPICAL
WAVE COULD BRING SIGNIFICANT RAIN TO GUATEMALA AND SOUTHERN MEXICO
ON THURSDAY INTO FRIDAY.
ALAMO...WPC (USA)
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