538
FXCA20 KWBC 181920
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
220 PM EST WED DEC 18 2024
FORECAST BULLETIN 18 DEC 2024 AT 20 UTC
IN NORTHERN AND EASTERN MEXICO ... A SURFACE COLD FRONT WILL BEGIN
TO TRAVERSE THE REGION THIS AFTERNOON AND WILL BEGIN TO DECAY AS
IT ENTERS SOUTHERN TAUMALIPAS BY THURSDAY EVENING. A LOW-LEVEL
HIGH PRESSURE SYSTEM ALSO IS EXPECTED TO DEVELOP THIS AFTERNOON IN
THE WEST GULF OF MEXICO ... HELPING IN INCREASING MOISTURE ALONG
SOUTHERN TAUMALIPAS AND NORTHERN VERACRUZ DUE TO THE MORE EASTERLY
FLOW. THIS PATTERN WILL REMAIN THROUGH SATURDAY. HIGHEST RAINFALL
TOTALS ARE EXPECTED TO OCCUR TODAY AND SATURDAY WITH MAXIMUM
TOTALS OF 15 - 25MM POSSIBLE ON BOTH DAYS. IN SOUTHERN VERACRUZ
... ENHANCED NORTHERLY FLOW IN THE GULF OF MEXICO AND WILL HELP
INCREASE MOISTURE IN THIS REGION AND INCREASING PRECIPITATION
CHANCES.
IN CENTRAL AMERICA ... A TROUGH SITUATED JUST OFF THE CARIBBEAN
COAST OF HONDURAS AND NICARAGUA WILL CONTINUE TO ASSIST IN
MOISTURE TRANSPORT INTO THIS REGION AND ENHANCING COASTAL
CONVECTION CHANCES. MOISTURE WILL CONTINUE TO INCREASE THROUGH
SATURDAY ... WHEN THE HIGHEST MAXIMUM RAINFALL TOTALS ARE
EXPECTED. CONSENSUS EXISTS WITHIN THE MODELS IN RAINFALL TOTALS
AND SPATIAL EXTENT.
ANOTHER REGION OF INTEREST IS IN COSTA RICA AND PANAMA ... LONG
FETCH MOISTURE FROM THE INTERIOR CARIBBEAN SEA AND STRENGTHENING
PANAMIAN LOW WILL INCREASE THE AVAILABLE MOISTURE IN THE REGION.
PRECIPITATION TOTALS WILL INCREASE THROUGH SATURDAY WITH MAXIMUM
RAINFALL TOTALS OF 20 - 45MM POSSIBLE ON SATURDAY.
IN THE CARIBBEAN ... IN THE NORTHWEST BAHAMAS ... THE
AFOREMENTIONED SURFACE COLD FRONT WILL INFLUENCE PRECIPITATION
PATTERNS STARTING THURSDAY MORNING THROUGH FRIDAY MORNING. AN
INCREASE IN MOISTURE FROM ENHANCED SOUTH-SOUTHEASTERLY FLOW AND
MID LEVEL VORTICITY ADVECTION WILL HELP IN INCREASE PRECIPITATION
CHANCES IN THE REGION.
ELSEWHERE IN THE CARIBBEAN ... IN THE EAST DOMINICAN REPUBLIC ...
INCREASE IN MOISTURE FROM THE EASTERLY TRADES AND ENHANCED LIFT
FROM A NEARBY TROUGH WILL INCREASE PRECIPITATION CHANCES TODAY AND
THURSDAY. UNCERTAINTY REMAINS WHETHER STRONGEST PRECIPITATION WILL
STAY OFF SHORE. EXPECT MAXIMUM RAINFALL TOTALS OF 15 - 25MM BOTH
DAYS AND POTENTIALLY GREATER IF PRECIPITATION MOVES FARTHER
INLAND. WIND SPEEDS ARE RELATIVELY SLOW ... WHICH MAY HELP KEEPING
THE HEAVIEST PRECIPITATION OFF SHORE.
ELSEWHERE IN THE CARIBBEAN ... IN THE LESSER ANTILLES ... ALONG
WITH THE EASTERLY TRADES ... AN AMPLIFYING VERTICALLY STACKED
TROUGH IN THE CENTRAL ATLANTIC WILL UNDULATE THE LOW LEVEL FLOW
AHEAD OF THE LESSER ANTILLES ... WHICH WILL DECREASE MOISTURE
TRANSPORT FROM THE EASTERLY TRADES.
IN TROPICAL SOUTH AMERICA ... AN INTENSIFYING PANAMIAN LOW WILL
CONTINUE TO DRIVE MOISTURE FROM THE PACIFIC INTO THE COAST OF
COLOMBIA ... WITH THE FLOW BECOMING MORE PARALLEL TO THE COAST
LINE BY FRIDAY ... WHEN THE HIGHEST MAXIMUM RAINFALL TOTALS ARE
LIKELY TO OCCUR. ELSEWHERE ... DIFFLUENCE IN NORTH CENTRAL BRAZIL
WILL INCREASE PRECIPITATION CHANCES ON THIS EVENING INTO TOMORROW
MORNING. ANOTHER AREA OF INTEREST IS ECUADOR AND NORTHERN PERU ON
THURSDAY INTO FRIDAY ... WHEN AN UPPER LEVEL TROUGH WILL BE
TRAVERSING THROUGH THIS REGION. THIS ... COUPLED WITH AMPLE
MOISTURE WILL ALSO ENHANCE PRECIPITATION CHANCES ... WHERE MAXIMUM
RAINFALL TOTALS WILL INCREASE THROUGH SATURDAY.
MEANWHILE ... THE NET/ITCZ WILL CONTINUE TO INFLUENCE
PRECIPITATION PATTERNS IN THE GUIANAS THROUGH THE FORECAST CYCLE.
TINOCO...(WPC)
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