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FXCA20 KWBC 051559
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EDT TUE MAY 05 2026
FORECAST BULLETIN 4 MAY 2026 AT 1600 UTC:
THE BAHAMAS AND CARIBBEAN:
A FRONTAL BOUNDARY EXTENDING FROM THE ATLANTIC INTO THE BAHAMAS
WILL CONTINUE TO FAVOR LOW-LEVEL MOISTURE CONVERGENCE OVER THE
ISLANDS, MAINTAINING PRECIPITATION IN THE REGION FROM TODAY
THROUGH WEDNESDAY. THUNDERSTORMS AND CONVECTIVE ACTIVITY ARE ALSO
EXPECTED, PARTICULARLY EARLY ON TUESDAY AS A RESULT OF THE
INSTABILITY GENERATED BY AN EASTWARD PROPAGATING UPPER-LEVEL
TROUGH, REFLECTED AT MID-LEVELS. A SLIGHT RISK FOR SEVERE WEATHER
EXISTS TODAY OVER THE BAHAMAS. ON WEDNESDAY, AN UPPER-LEVEL HIGH
WILL PROPAGATE EASTWARD FROM MEXICO INTO THE GULF, BRINGING MORE
STABILITY TO THE REGION. SOME UPPER-LEVEL DIFFLUENCE IS
ANTICIPATED TO HAPPEN ALONG THE PERIPHERY OF THE HIGH CAUSING SOME
CONVECTION OVER EASTERN CUBA, THE SOUTHERN BAHAMAS, AND TURKS AND
CAICOS.
OVER THE EASTERN CARIBBEAN, SOME SHALLOW CONVECTION IS LIKELY FROM
WEDNESDAY THROUGH THURSDAY AS THE UPPER-LEVEL TROUGH PROPAGATES,
HOWEVER A MID-LEVEL RIDGE IN THE CARIBBEAN, AND RELATIVELY DRY AIR
WILL LIMIT PRECIPITATION IN THE REGION. DAILY PRECIPITATION DUE TO
DIURNAL HEATING AND LOCAL EFFECTS IS LIKELY THROUGHOUT THE
FORECAST PERIOD.
MEXICO AND CENTRAL AMERICA:
CONDITIONS ARE EXPECTED TO REMAIN FAIRLY STABLE OVER MEXICO
THROUGH LATE WEDNESDAY, WITH DRY AIR PREVAILING IN THE REGION AND
A HIGH AT MID- AND UPPER-LEVELS. A MORE ACTIVE PRECIPITATION
PATTERN IS EXPECTED THURSDAY INTO FRIDAY, PARTICULARLY OVER
NORTHEASTERN MEXICO AND ALONG THE SIERRA MADRE ORIENTAL. THIS WILL
HAPPEN AS A FRONTAL BOUNDARY APPROACHES THE SOUTHERN UNITED STATES
AND EXTENDS INTO NORTHEASTERN MEXICO, PROMOTING LOW-LEVEL
CONVERGENCE IN THE AREA AND INCREASING MOISTURE IN THE REGION. AT
UPPER-LEVELS, SPEED DIVERGENCE IS ALSO EXPECTED, WHICH COMBINED
WITH THE PRESENCE OF MID-LEVEL SHORTWAVE TROUGHS WILL SUPPORT
CONVECTIVE ACTIVITY AND THUNDERSTORMS. THE HIGHEST ACCUMULATIONS
ARE ANTICIPATED TO RANGE FROM 20-45MM FROM THURSDAY THROUGH FRIDAY
OVER NORTHEASTERN MEXICO.
COSTA RICA AND PANAMA WILL RECEIVE LIGHT TO MODERATE PRECIPITATION
THROUGHOUT THE FORECAST PERIOD. THIS RAINFALL PATTERN IS LINKED TO
THE CONDITIONS AT LOWER-LEVELS THAT WILL FAVOR WIND CONVERGENCE
AND MOISTURE ADVECTION, MAINLY FROM THE CARIBBEAN. THE HIGHEST
LEVELS OF RAINFALL ACCUMULATIONS ARE EXPECTED TODAY THROUGH
WEDNESDAY, AS A LOW-LEVEL TROUGH PROPAGATES THROUGH THE REGION
ADVECTING MOISTURE, BUT LOWER ACCUMULATIONS ARE ANTICIPATED
TOWARDS THE END OF THE WORKWEEK AS THE PRECIPITABLE WATER
AVAILABILITY DECREASES.
TROPICAL SOUTH AMERICA:
HEAVY PRECIPITATION IS ANTICIPATED TODAY THROUGH WEDNESDAY MORNING
OVER THE GUIANAS, THE AMAZON DELTA AND THE EASTERN-TO-CENTRAL
AMAZON BASIN IN BRAZIL. THIS PRECIPITATION IS ASSOCIATED WITH THE
PRESENCE OF THE ITCZ AND THE NET THAT WILL PROMOTE LOW-LEVEL
MOISTURE CONVERGENCE, WHILE A PROPAGATING LOW-LEVEL TROUGH ADVECTS
MOISTURE IN THE AREA. UPPER-LEVEL DIFFLUENCE IS ALSO ANTICIPATED
ALONG THE PERIPHERY OF THE BOLIVIAN HIGH, PROMOTING INSTABILITY
AND THE DEVELOPMENT OF THUNDERSTORMS.
LIGHT TO MODERATE PRECIPITATION IS ALSO EXPECTED TODAY THROUGH
THURSDAY OVER THE WESTERN AMAZON BASIN WHERE A LOW-LEVEL TROUGH
WILL PROMOTE LOW-LEVEL CONVERGENCE.
RAINFALL IS ALSO ANTICIPATED OVER THE PACIFIC COAST OF ECUADOR AND
COLOMBIA THROUGHOUT THE FORECAST PERIOD WITH MOISTURE BEING
ADVECTED FROM THE PACIFIC. WITH RELATIVELY WEAK WINDS AT
LOW-LEVELS , ACCUMULATIONS ARE EXPECTED TO REMAIN ON THE LOWER END
TODAY THROUGH WEDNESDAY. HOWEVER, AN INCREASE IN ACCUMULATIONS IS
LIKELY FROM WEDNESDAY THROUGH THURSDAY, WITH LOW-LEVEL FLOW
PERPENDICULAR TO THE COAST AND THE PRESENCE OF A SHORTWAVE TROUGH
ENHANCING UPPER-LEVEL DIVERGENCE.
BY THE END OF THE FORECAST PERIOD, A DRYING TREND IS ANTICIPATED
THROUGHOUT THE REGION, WITH MOST OF THE PRECIPITATION EXPECTED
OVER THE EASTERN AMAZON BASIN, DUE TO LOW-LEVEL CONVERGENCE AND
OVER THE PACIFIC COAST DUE TO MOISTURE ADVECTION. LIGHT RAINFALL
AND THUNDERSTORMS ARE LIKELY OVER THE REST OF THE REGION DUE TO
DIURNAL CONVECTION, MOISTURE ADVECTION AND LOCAL EFFECTS.
RIVERA-TORRES...(WPC)
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