TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
211 PM EDT FRI SEP 29 2023

FORECAST BULLETIN 29 SEP 2023 AT 1800 UTC: THE NATIONAL HURRICANE
CENTER IS MONITORING TWO TROPICAL STORMS IN THE ATLANTIC BASIN.
TROPICAL STORM PHILIPPE...WHICH CONTINUES TO HAVE A HIGHER THAN
NORMAL UNCERTAINTY...AND TROPICAL STORM RINA. BOTH TROPICAL STORMS
ARE FORECAST BY THE NATIONAL HURRICANE CENTER TO REMAIN AWAY FROM
LAND AREAS IN THE CARIBBEAN. HOWEVERâ€TROPICAL STORM PHILIPPE IS
MOVING VERY SLOWLY AND...COULD CAUSE AN INCREASE IN MOISTURE
ACROSS THE NORTHEAST CARIBBEAN AND THEN CAUSE LOCALLY SCATTERED TO
NUMEROUS SHOWERS ACROSS THE LEEWARD ISLANDS INTO PR/USVI THIS
WEEKEND.

A SFC HIGH PRESSURE EXITING THE EAST COAST OF CANADA WILL MOVE
INTO THE NW ATLANTIC. A SFC LOW PRESSURE WILL DEVELOP JUST EAST OF
THE MID ATLANTIC COAST OF THE US AND MOVE SLOWLY TO THE EAST. A
TROUGH ACROSS THE SOUTHWESTERN GULF OF MEXICO...INTO THE YUCATAN
PENINSULA WILL PREVAIL OVER THE AREA FOR THE NEXT FEW DAYS. THERE
IS ALSO A TROPICAL WAVE ALONG 95W BRINGING MOISTURE AND SHOWER
ACTIVITY TO PORTIONS OF CENTRAL AMERICA AND SOUTHERN MEXICO. IN
THE MID LEVELS...A BROAD HIGH PRESSURE IS LOCATED IN THE
ATLANTIC...WITH ITS CENTER TO THE NORTH OF THE GREATER ANTILLES
UNTIL SATURDAY. FROM SUNDAY INTO MONDAYâ€A TILTED MID-LEVEL
TROUGH FROM THE WESTERN ATLANTIC INTO THE GULF OF MEXICO WILL BE
ASSOCIATED WITH A MID-LEVEL LOW ACROSS THE WESTERN ATLANTIC. THERE
IS AN UPPER LEVEL LOW ACROSS THE SOUTHERN CARIBBEAN INTO THE NORTH
PORTION OF SOUTH AMERICA...MOVING WEST INTO CENTRAL AMERICA
THROUGH THIS WEEKEND...WHICH WILL HELP IN THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AMERICA THIS WEEKEND.

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. SATURDAY INTO SUNDAY IS STILL
FORECAST TO BE THE WETTEST PERIOD ACROSS THE AREA...AS IT HAS
SUPPORT FROM AN UPPER TROUGH. RAINFALL TOTALS ON SATURDAY INTO
SUNDAY WILL HAVE MAX VALUES OF 25-50MM. LESSER AMOUNTS OF RAIN ARE
EXPECTED TODAY INTO SATURDAY...WITH MAX VALUES BETWEEN 20-35MM AND
15-25MM ON SUNDAY INTO MONDAY. THE WEST COAST OF OF MEXICO IS
EXPECTED TO OBSERVE SHOWERS AND THUNDERSTORMS EACH DAY FOR THE
NEXT 3 DAYS...THOUGH GENERALLY IN THE ORDER OF 05-10MM/DAY WITH
MAX UP TO 25MM. HOWEVERâ€ISOLATED SECTIONS OVER FROM JALISCO TO
OAXACA ARE FORECAST TO OBSERVE 20-35MM. EAST CENTRAL TO NORTHEAST
FROM VERACRUZ TO TAMAULIPAS IS FORECAST TO OBSERVE RAIN TODAY INTO
SATURDAY MORNING...WITH MAX TOTALS UP TO 10MMâ€BUT MINIMAL RAIN
FOR THE REST OF THE WEEKEND INTO MONDAY.

IN THE CARIBBEAN...MOST OF THE RAINFALL ACROSS THE LESSER ANTILLES
IS EXPECTED TO BE DUE TO BRIEF SHOWERS UNDER A NORTHEASTERLY WIND
FLOW. LOCALLY INDUCED SHOWERS AND THUNDERSTORMS COULD AFFECT
ISOLATED AREAS OF SOUTHWESTERN PR AND PORTIONS OF HISPANIOLA IN
THE AFTERNOON HOURS EACH DAY...WHICH COULD AMOUNT TO OVER 25-35MM.
OTHERWISE...BRIEF SHOWERS WOULD AFFECT THE WINDWARD SIDE OF THE
GREATER ANTILLES. THE ADVECTED SHOWERS EXPECTED MAY CAUSE RAINFALL
TOTALS OF UP TO 10MM ACROSS HISPANIOLA...PUERTO RICO AND USVI EACH
DAY...WITH THE EXCEPTION OF THE VERY ISOLATED AREAS THAT WERE
MENTIONED. 10-15MM IS POSSIBLE ACROSS THE LESSER ANTILLES EACH DAY
THROUGH THE WEEKEND.

IN CENTRAL AMERICA...THE MOISTURE THAT IS AVAILABLE WILL HELP IN
THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND.
MOST AREAS OF CENTRAL AMERICA ARE 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 30-60MM TODAY INTO SATURDAY WITH THE TRAILING MOISTURE
FROM THE TROPICAL WAVE OVER THE AREA. THEN MAX TOTALS OF 20-45MM
ARE FORECAST FROM SATURDAY INTO SUNDAYâ€THEN LESSER RAINFALL
AMOUNTS ARE FORECAST ON SUNDAY INTO MONDAY.

IN NORTHERN SOUTH AMERICA...SOUTHWESTERN COLOMBIA INTO ECUADOR ARE
THE AREAS WITH THE MOST SIGNIFICANT RAINFALL TODAY INTO FRIDAY
WITH TOTALS UP TO AROUND 60MM AS WELL AS SUNDAY INTO MONDAY.
NORTHEASTERN COLOMBIA AND MOST OF VENEZUELA ARE EXPECTED TO
OBSERVE UP TO 25MM TODAY. SATURDAY INTO SUNDAY COULD HAVE MORE
THUNDERSTORM ACTIVITY OVER CENTRAL TO EASTERN COLOMBIA...WITH
RAINFALL UP TO 45MM. NORTHEASTERN PERU IS FORECAST TO OBSERVE
GENERALLY 05-10MM AND UP TO 25MM TODAY AND THROUGH THE WEEKEND.
THE GUIANAS ARE STILL FORECAST TO OBSERVE MINIMAL RAINFALL EACH
DAY...IF ANY.

POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT  30/00  30/12  01/00  01/12   02/00  02/12  03/00 
03/12
TW   19N  95W    97W  100W    102W   104W    106W   108W   110W  
112W

A TROPICAL WAVE IS INITIALIZED AT 95W AND TO THE SOUTH OF 19N. IT
HAS ABUNDANT MOISTURE ASSOCIATED WITH IT AND IT IS OVER SOUTHERN
MEXICO. THE TROPICAL WAVE IS FORECAST TO CONTINUE MOVING WEST OVER
THE NEXT FEW DAYS. THIS TROPICALâ€WITH ITS TRAILING MOISTURE WAVE
COULD BRING SIGNIFICANT RAIN TO GUATEMALA AND SOUTHERN MEXICO
TODAY INTO EARLY SATURDAY.



ALAMO...WPC (USA)