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FXCA20 KWBC 141820
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 PM EDT THU MAY 14 2026
NOTE: UPDATED POSITIONS OF TROPICAL WAVES
FORECAST BULLETIN 14 MAY 2026 AT 1817 UTC:
THE BAHAMAS AND CARIBBEAN:
A FRONTAL BOUNDARY OVER THE ATLANTIC EXTENDING NORTH OF THE
BAHAMAS WILL INCREASE THE PRECIPITABLE WATER AVAILABILITY,
GENERATE LOW-LEVEL TROUGHS AND ENHANCE LOW-LEVEL MOISTURE
CONVERGENCE OVER THE BAHAMAS AND CUBA. THESE FACTORS WILL BRING
PRECIPITATION TO THE REGION TODAY THROUGH FRIDAY MORNING. AT UPPER
LEVELS, AN EASTWARD PROPAGATING TROUGH WILL INCREASE DIVERGENCE,
PARTICULARLY OVER THE BAHAMAS. THIS, COMBINED WITH LOW-LEVEL
INSTABILITY, WILL SUPPORT THE DEVELOPMENT OF THUNDERSTORMS AND
CONVECTIVE ACTIVITY. A MARGINAL RISK FOR SEVERE WEATHER EXISTS
FROM TODAY THROUGH FRIDAY. LOW-LEVEL CONVERGENCE, AND MOISTURE
ADVECTION WILL CONTINUE TO BE SUPPORTED OVER PORTIONS OF CUBA AND
THE BAHAMAS BY THE FRONTAL BOUNDARY FROM FRIDAY THROUGH SATURDAY.
SIMILARLY, UPPER-LEVEL DIVERGENCE ASSOCIATED WITH THE TROUGH WILL
CONTINUE SUPPORTING SEVERE WEATHER OVER THE BAHAMAS EARLY ON
SATURDAY. FROM SATURDAY THROUGH SUNDAY, THE LOW-LEVEL FLOW WILL
BECOME MORE EASTERLY AS THE FRONTAL BOUNDARY EXISTS IN THE REGION,
BUT LIGHT PRECIPITATION IS EXPECTED DUE TO MOISTURE ADVECTION AND
THE PROPAGATION OF LOW-LEVEL TROUGHS. SOME SUPPORT IS ALSO
EXPECTED FROM UPPER-LEVELS FOR THUNDERSTORMS AS THE UPPER-LEVEL
TROUGH PROPAGATES SLOWLY.
ELSEWHERE IN THE CARIBBEAN, DAILY RAINFALL DUE TO DIURNAL HEATING,
MOISTURE ADVECTION, THE PROPAGATION OF LOW-LEVEL TROUGHS, AND
LOCAL EFFECTS IS LIKELY. RELATIVELY STABLE CONDITIONS WILL
PREVAIL, PARTICULARLY OVER THE EASTERN CARIBBEAN, THROUGHOUT THE
FORECAST PERIOD DUE TO THE PRESENCE OF UPPER-LEVEL RIDGING.
MEXICO AND CENTRAL AMERICA:
OVER MEXICO, EXPECT PRECIPITATION ALONG THE SIERRA MADRE DEL SUR
TODAY THROUGH FRIDAY DUE TO A LOW-LEVEL TROUGH OVER THE PACIFIC
ADVECTING MOISTURE INTO THE REGION. OVER THE YUCATAN PENINSULA
INTO CHIAPAS, ANOTHER LOW-LEVEL TROUGH WILL ADVECT MOISTURE INTO
THE REGION, BRINGING RAINFALL TODAY. SIMILAR CONDITIONS ARE
EXPECTED FROM FRIDAY THROUGH SUNDAY MORNING, WITH AN INCREASE IN
PRECIPITATION OVER CENTRAL MEXICO DUE TO SHORTWAVE TROUGHS. A
LOW-LEVEL TROUGH PROPAGATING OVER THE CARIBBEAN COAST OF CENTRAL
AMERICA WILL AID THE DEVELOPMENT OF SHOWERS OVER COSTA RICA TODAY
THROUGH FRIDAY, AND OVER NICARAGUA AND HONDURAS, AND EL SALVADOR
FROM EARLY SATURDAY THROUGH SUNDAY. ACCUMULATIONS ARE EXPECTED TO
REMAIN RELATIVELY LOW, DUE TO AN UPPER-LEVEL RIDGE PREVAILING OVER
NORTHERN CENTRAL AMERICA. HOWEVER, STRONG LOW-LEVEL WINDS COULD
PROVIDE SUPPORT FOR HIGH, ISOLATED RAINFALL ACCUMULATIONS OVER THE
CARIBBEAN COAST OF COSTA RICA.
TROPICAL SOUTH AMERICA:
IN COLOMBIA, A LOW-LEVEL TROUGH WILL PROMOTE LIGHT TO MODERATE
PRECIPITATION OVER THE ANDES REGION TODAY THROUGH FRIDAY. WITH AN
UPPER-LEVEL TROUGH APPROACHING THE GREATER ANTILLES, THERE WILL BE
AN INCREASE IN PRECIPITATION AND CONVECTIVE ACTIVITY. FURTHER
SUPPORT FOR THE DEVELOPMENT OF CONVECTIVE ACTIVITY IS EXPECTED
FROM UPPER-LEVELS FROM SATURDAY THROUGH SUNDAY IN COLOMBIA. OVER
THE PACIFIC COAST OF COLOMBIA AND ECUADOR, DAILY PRECIPITATION IS
FORECAST WITH MOISTURE BEING ADVECTED FROM THE PACIFIC OCEAN ONTO
THE COAST BY THE LOW-LEVEL FLOW. ELSEWHERE IN TROPICAL SOUTH
AMERICA, PRECIPITATION WILL BE DRIVEN BY MOISTURE ADVECTION,
LOW-LEVEL MOISTURE CONVERGENCE, DIURNAL HEATING, OROGRAPHIC
LIFTING AND OTHER LOCAL EFFECTS. THE HIGHEST ACCUMULATIONS ARE
ANTICIPATED OVER THE AMAZON REGION OF COLOMBIA, NORTHERN PERU AND
WESTERN BRAZIL. OVER THE NORTHEAST COAST OF THE CONTINENT,
PARTICULARLY THE GUIANAS, LOW-LEVEL TROUGHS AND THE ITCZ WILL
BRING RAINFALL EACH DAY OF THE FORECAST PERIOD. AS THE LOW-LEVEL
TROUGH PROPAGATES, IT WILL INCREASE PRECIPITATION OVER PORTIONS OF
VENEZUELA, PARTICULARLY FROM SATURDAY THROUGH SUNDAY.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 15/00 15/12 16/00 16/12 17/00 17/12 18/00 18/12
TW 12N 48W 53W 56W 60W 66W 71W 75W 79W 82W
RIVERA-TORRES...(WPC)
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