853
FXCA20 KWBC 161801
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
100 PM EST TUE DEC 16 2025
FORECAST BULLETIN 16 DECEMBER 2025 AT 1805 UTC:
OVER THE BAHAMAS AND THE CARIBBEAN REGION, THE BASE OF AN UPPER
LEVEL TROUGH REACHES CUBA AND HISPANIOLA. A SERIES OF SHORTWAVE
TROUGHS EMBEDDED IN THE MID TO UPPER LEVEL TROUGH ARE PROPAGATING
OVER THE BAHAMAS, CUBA AND HISPANIOLA ON TUESDAY AND ARE EXPECTED
TO CONTINUE OVER THE REGION INTO EARLY WEDNESDAY. A WEAKENING
FRONTAL BOUNDARY EXTENDS OVER THE BAHAMAS AND INTO NORTH CUBA,
WHILE A WEAK SHEAR LINE IS EXPECTED TO EXTEND INTO TURKS AND
CAICOS, THE WINDWARD PASSAGE, AND JAMAICA BY TUESDAY EVENING.
TUESDAY IS EXPECTED TO BE THE DAY WITH THE HEAVIEST PRECIPITATION
OVER THE REGION DUE TO THE PRESENCE OF THE MID TO UPPER LEVEL
TROUGH AND THE WEAKENING FRONTAL BOUNDARY. THE SOUTH BAHAMAS CAN
EXPECT MAXIMA OF 20-45MM WITH A SLIGHT RISK OF SEVERE WEATHER ON
TUESDAY. THE NORTHERN COAST OF CUBA CAN EXPECT MAXIMA OF 20-35MM.
THE REST OF CUBA, THE BAHAMAS, TURKS AND CAICOS, AND JAMAICA CAN
EXPECT LOCAL MAXIMA OF 15MM. AS THE MID TO UPPER TROUGH CONTINUES
TO PROPAGATE TO THE EAST, A DRYING TREND IS INITIATING OVER THE
REGION, WHILE A MID TO UPPER LEVEL RIDGE DEVELOPS, CENTERED OVER
THE CARIBBEAN SEA, FAVORING THE PRESENCE OF THE TRADE WIND
INVERSION CAP INCREASES ON WEDNESDAY AND THURSDAY. IN ADDITION,
THE EASTERLY TRADE WINDS ARE ADVECTING DRIER AIR INTO THE REGION,
WITH WEAK TROUGHS EMBEDDED IN THE TRADES. THESE WILL FAVOR
LOCALIZED SHOWERS THAT ARE LIKELY TO LEAVE TRACE AMOUNTS OF TOTAL
PRECIPITATION OVER THE LESSER ANTILLES AND INTO PARTS OF THE
GREATER ANTILLES ON WEDNESDAY AND THURSDAY.
IN CENTRAL AMERICA, A DISORGANIZED RIDGING PATTERN IN THE MID TO
UPPER LEVELS IS PRESENT, WHILE IN THE LOWER LEVELS, MOIST
NORTHEASTERLY FLOW FROM THE WESTERN CARIBBEAN SEA IS FAVORING
MOISTURE CONVERGENCE ALONG THE COASTS OF HONDURAS AND NICARAGUA ON
TUESDAY. IN COSTA RICA AND PANAMA, LOW LEVEL CIRCULATION
ASSOCIATED WITH THE MONSOON TROUGH AND THE PANAMANIAN LOW IS
FAVORING MOIST ONSHORE FLOW INTO THE REGION, WHERE LIGHT TO
MODERATE PRECIPITATION IS EXPECTED ON TUESDAY, AND DECREASE
SLIGHTLY INTO WEDNESDAY AND THURSDAY AS THE AMOUNT OF AVAILABLE
MOISTURE DECREASES AS DRIER AIR IS ADVECTED IN THE EASTERLY TRADE
WINDS FROM THE CARIBBEAN SEA. ON TUESDAY, NORTH HONDURAS CAN
EXPECT MAXIMA OF 30-60MM, WHILE EXTREME EAST HONDURAS INTO EAST
NICARAGUA EXPECT MAXIMA OF 20-40MM. ELSEWHERE IN CENTRAL AMERICA,
EXPECT MAXIMA BETWEEN 15-25MM. AS MOISTURE DECREASES ON WEDNESDAY,
EXPECT MAXIMA TO RANGE BETWEEN 15-20MM THROUGHOUT THE REGION. AS
THE MID TO UPPER LEVEL RIDGE HAS STRENGTHENED BY THURSDAY, TRADE
WIND INVERSION CAPS REACH CENTRAL AMERICA, WHILE AVAILABLE
MOISTURE REMAINS LOW. AS THESE CONDITIONS COME INTO PLACE, THE
POTENTIAL FOR DEEP CONVECTION OVER THE REGION DECREASES. EXPECT
MAXIMA OF 15-30MM IN GUATEMALA WITH A MOIST TROUGH ENTERING THE
REGION, WHILE EAST HONDURAS/NORTHEAST NICARAGUA AND COSTA RICA
INTO PANAMA, CAN EXPECT MAXIMA OF 15-20MM ON THURSDAY.
IN NORTHERN SOUTH AMERICA, MOST OF THE MOISTURE IS REMAINING OVER
THE AMAZON RIVER BASIN AND TOWARDS THE CENTRAL REGIONS OF THE
CONTINENT. DRIER AIR IS BEING ADVECTED FROM THE CENTRAL ATLANTIC
THROUGH THE EASTERLY TRADE WINDS AND MAINTAINING PORTIONS OF EAST
COLOMBIA, VENEZUELA, AND THE GUIANAS DRY OVER THE NEXT THREE DAYS.
THE EXCEPTION IS OVER THE EASTERN GUIANAS AND INTO AMAPA-BRASIL,
DUE TO THE MOIST PLUME ASSOCIATED WITH THE ITCZ, WHERE MOISTURE
TRANSPORT IS TAKING PLACE INTO THE REGION. AS THIS MOISTURE IS
ENTERING FROM THE EAST, IT IS FAVORING MOISTURE CONVERGENCE ALONG
THE COASTAL REGIONS FROM SURINAME INTO AMAPA, WHERE FRENCH GUIANA
AND PORTIONS OF NORTH AMAPA ARE EXPECTED TO SEE THE HEAVIEST
PRECIPITATION OVER THE NEXT THREE DAYS. ON TUESDAY, DEEP
CONVECTION IS EXPECTED TO FAVOR MAXIMA OF 35-70MM. OVER THE AMAZON
RIVER BASIN, A RAPIDLY PROPAGATING FRONTAL BOUNDARY IS FAVORING
PREFRONTAL TROUGHS, WHERE MOISTURE IS CONVERGING AND FAVORING
MAXIMA OF 20-35MM OVER THE CENTRAL AND WESTERN AMAZON BASIN ON
TUESDAY. ON WEDNESDAY, FRENCH GUIANA AND AMAPA WILL CONTINUE TO
SEE THE TRANSPORT OF MOISTURE INTO THE REGION, AND MAXIMA OF
25-50MM ARE EXPECTED. OVER THE AMAZON BASIN, MOISTURE AND
TROUGHING WILL HAVE UPPER AIR SUPPORT FROM THE BOLIVIAN HIGH
PERIPHERY INTERACTING WITH A WEAK TROUGH AXIS ASSOCIATED WITH THE
NORTHEAST BRASILIAN UPPER TROUGH, AND FAVOR GENERALIZED MAXIMA OF
20-45MM OVER THE WEST AND CENTRAL AMAZON BASIN. SIMILAR CONDITIONS
REMAIN ON THURSDAY, AND THE AMAZON BASIN CAN EXPECT MAXIMA OF
20-35MM. A SLIGHT DECREASE IN WIND SPEED OVER THE EASTERN GUIANAS
WILL FAVOR MAXIMA OF 20-45MM IN NORTH FRENCH GUIANA, AND
GENERALIZED MAXIMA OF 15-25 IN AMAPA, AND THE REST OF THE EASTERN
GUIANAS.
MEXICO CAN EXPECT A GENERAL DRY PATTERN AS THE REGION IS EXPECT TO
SEE LOW AMOUNTS OF AVAILABLE MOISTURE. ALTHOUGH A DEEP UPPER
TROUGH IS EXPECTED TO REACH SOUTHWEST MEXICO BY WEDNESDAY INTO
THURSDAY, THE ABSENCE OF ENOUGH MOISTURE WILL IMPACT THE REGION
AND PRECIPITATION IS EXPECTED TO REMAIN AS LOCALIZED TRACE AMOUNTS
THROUGHOUT THE NEXT THREE DAYS.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYP SOF INIT 17/00 17/12 18/00 18/12 19/00 19/12 20/00
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