FXCA20 KWBC 311848
PMDCA 

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 PM EDT WED MAY 31 2023

FORECAST BULLETIN FROM 31 MAY 2023 AT 1900 UTC: A RELATIVE ACTIVE
PATTERN CONTINUES TO BE EXPECTED ACROSS THE TROPICAL REGION FOR
THE REST OF THE WEEK. THERE ARE A NUMBER OF SURFACE TROUGHS OVER
THE ATLANTIC BASIN AND THREE EASTERLY WAVES ACROSS THE LOWER
LATITUDES OF THE TROPICS...MAINLY CROSSING NORTHERN SOUTH AMERICA.
THE AVAILABLE MOISTURE IS NEAR TO BELOW NORMAL ACROSS THE GULF OF
MEXICO...BUT ABOVE NORMAL ACROSS THE CARIBBEAN INTO THE
SOUTHWESTERN ATLANTIC...AS IT CONTINUES TO INCREASE...WHICH WILL
HELP IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE
GREATER ANTILLES. AT THE SURFACE...THERE IS A LOW ACROSS THE
WESTERN ATLANTIC WITH A TROUGH EXTENDING INTO THE BAHAMAS. THERE
IS ALSO A LOW-PRESSURE ACROSS THE GULF OF MEXICO...JUST WEST OF
THE STATE OF FLORIDA. THE WINDS ARE GENERALLY LIGHT ACROSS THE
CARIBBEAN AND THE GULF OF MEXICO...WITH ONLY A SHORT LOW LEVEL JET
EAST OF THE LESSER ANTILLES AND OVER NORTHERN MEXICO. AT THE MID
LEVELS...THERE IS A THROUGH OVER THE GULF OF MEXICO...THAT WILL
CONTINUE MOVING EAST OVER THE NEXT FEW DAYS. ITS AXIS WILL BE OVER
WESTERN CUBA BY FRIDAY. THIS MID-LEVEL TROUGH WILL HELP INCREASE
INSTABILITY AND IS ONE OF THE MAIN REASONS WHY SHOWERS AND
THUNDERSTORMS ARE EXPECTED OVER CUBA THIS AFTERNOON AND EVENING.
AS THE TOUGH CONTINUES TO MOVE EAST...IT WILL WEAKEN...BUT IT WILL
CONTINUE TO PROMOTE THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS
ACROSS THE NORTHERN CARIBBEAN AND THE BAHAMAS OVER THE NEXT FEW
DAYS. IN THE UPPER LEVELS...THERE IS ALSO A TROUGH ACROSS THE
CENTRAL GULF OF MEXICO AND IT IS EXPECTED TO MOVE EAST OVER THE
NEXT FEW DAYS...WITH ITS AXIS OVER CUBA ON FRIDAY AS WELL. THIS
UPPER TROUGH WILL PROVIDE ADDITIONAL SUPPORT TO THE DEVELOPMENT OF
THUNDERSTORMS ACROSS THE NORTHERN CARIBBEAN AND THE BAHAMAS.

SOME OF THE LOCAL GUIDANCE ALGORITHMS SHOW THAT THERE IS THE
POTENTIAL FOR STRONG THUNDERSTORMS ACROSS THE CARIBBEAN...CENTRAL
AND NORTHERN SOUTH AMERICA. THE EGDI ALGORITHM FAVORS SCATTERED
THUNDERSTORMS ACROSS THE AFOREMENTIONED AREAS FOR THE NEXT THREE
DAYS. ALSO...THE GR02T THE POTENTIAL FOR STRONG THUNDERSTORMS AND
HAIL... IS ENHANCED OVER CUBA THIS AFTERNOON INTO THE
EVENING...WITH A MUCH WEAKER SIGNATURE BEING PRESENTED THEREAFTER.

OVERALL...MOST OF MEXICO WILL HAVE A LOW CHANCE OF SIGNIFICANT
RAINFALL OVER THE NEXT FEW DAYS...WITH THE EXCEPTION OF SOUTHERN
AND EASTERN MEXICO WHERE A FEW AREAS CAN OBSERVE MAXIMAS BETWEEN
15-25MM. CENTRAL AND NORTHERN SOUTH AMERICA APPEAR TO BE VERY
ACTIVE. PARTLY BECAUSE OF THE PRESENCE OF THE ITCZ AND THE NET
OVER CENTRAL AND NORTHERN SOUTH AMERICA...CAUSING VERY DEEP
MOISTURE AND CONVERGENCE OVER THE AREA. EACH DAY IN THE FORECAST
PERIOD WE CAN EXPECT RAINFALL MAXIMA THAT COULD BE BETWEEN 20 AND
45MM...WHILE ISOLATED AREAS COULD HAVE AS MUCH AS 50-70MM OVER
PORTIONS OF COSTA RICA...ECUADOR...COLOMBIA...AND A SMALL PORTION
OF NORTHWESTERN PERU. THE MID AND UPPER LEVEL TROUGHS OVER THE
GULF WILL CAUSE AN INCREASE IN INSTABILITY AND THUNDERSTORM
POTENTIAL OVER THE GREATER ANTILLES OVER THE NEXT FEW DAYS. THE
PRESENCE OF A DEVELOPING SURFACE LOW PRESSURE SYSTEM ACROSS THE
SOUTHWESTERN ATLANTIC WILL CAUSE ABUNDANT MOISTURE TO BE PULLED
FROM THE SOUTHERN CARIBBEAN OVER THE GREATER ANTILLES BY THE
LATTER PART OF THIS WEEK...PROVIDING ENOUGH MOISTURE TO HAVE
PERSISTENT SHOWER ACTIVITY OVER THE GREATER ANTILLES THROUGH THE
LATTER PART OF THE WEEK AND INTO THE WEEKEND.


POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE  SOF INIT 01/00 01/12 02/00 02/12 03/00 03/12 04/00
TW    11N  46W  50W   53W   57W   61W   64W   67W   70W
TW    13N  56W  58W   60W   62W   64W   67W   70W   73W
TW    11N  77W  79W   81W   84W   DISS  ---   ---   ---  

A TROPICAL WAVE IS INITIALIZED AT 46W AND 11N. THIS WAVE IS
FORECAST TO ARRIVE IN THE GUIANAS BY LATE TONIGHT/EARLY THURSDAY.
FOR THE REST OF TODAY INTO EARLY THURSDAY...THE
AMAPA-BRASIL/FRENCH GUIANA REGION CAN EXPECT MAXIMA OF 15-25MM.
THE WAVE IS FORECAST TO BE OVER THE SURINAME/GUYANA BORDER AND MAY
EXPECT SIMILAR AMOUNTS THROUGH THURSDAY. BY FRIDAY EVENING...THE
TROPICAL WAVE REACHES EASTERN VENEZUELA. EAST VENEZUELA IS
FORECAST A MAXIMA OF 20-35MM...WHILE RORAIMA IS FORECAST FOR
ISOLATED MAXIMA OF 15-25MM.

A TROPICAL WAVE IS INITIALIZED AT 56W AND SOUTH OF 13N...OVER
SURINAME. FOR THE REST OF TODAY INTO EARLY THURSDAY...EXPECT
MAXIMA OF 15-25MM. THE TROPICAL WAVE IS FORECAST TO EACH EASTERN
VENEZUELA BY THURSDAY EVENING...WHERE THE FORECAST IS FOR A
RAINFALL MAXIMA OF 15-25MM. BY FRIDAY EVENING...THE WAVE REACHES
CENTRAL VENEZUELA...WHERE A RAINFALL MAXIMA OF 20-35MM IS FORECAST.

A TROPICAL WAVE IS INITIALIZED OVER 76W AND SOUTH OF 11N....JUST
OVER WESTERN COLOMBIA. FOR THE REST OF TODAY INTO EARLY
THURSDAY...A RAINFALL MAXIMA OF 35-70MM IS FORECAST FOR PORTIONS
OF ECUADOR AND NORTHWESTERN PERU...WHILE MOST OF COLOMBIA WILL
HAVE A MAXIMA OF 20-45MM. THE TROPICAL WAVE WILL MOVE QUICKLY TO
THE WEST...WITH A VERY WEAK REPRESENTATION DETECTED ALONG 84W NEAR
THE COSTA RICA/NICARAGUA BORDER. ON FRIDAY INTO EARLY
FRIDAY...COSTA RICA IS FORECAST TO OBSERVE AN INCREASE IN SHOWERS
AND THUNDERSTORMS ON THE EAST SIDE OF THE WAVE AXIS...CAUSING
RAINFALL MAXIMA BETWEEN 25 AND 50MM. THE TROPICAL WAVE IS EXPECTED
TO DISSIPATE THEREAFTER.

ALAMO/ACOSTA...WPC (USA)
$$