107
FXCA20 KWBC 312027
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 PM EST TUE DEC 31 2024
NOTE: THE TROPICAL DISCUSSION WILL NOT BE AVAILABLE ON NEW YEARS
DAY. THE NEXT DISCUSSION WILL BE AVAILABLE ON JANUARY 2ND 2025.
FORECAST BULLETIN 31 DEC 2024 AT 20 UTC:
FRONT IN NORTHERN PORTIONS OF THE BASIN: A POTENT UPPER TROUGH AND
EXTRATROPICAL CYCLONE IS PROPAGATING EASTWARD ACROSS THE GREAT
LAKES. THIS SYSTEM IS SUSTAINING A POTENT COLD FRONT THAT IS
ALREADY PROPAGATING ACROSS THE NORTHERN GULF OF MEXICO. BY TUESDAY
EVENING EXPECT THE FRONT ALONG THE FLORIDA PANHANDLE INTO NORTHERN
TAMAULIPAS. BY WEDNESDAY EVENING EXPECT THE FRONT ACROSS THE
NORTHWEST BAHAMAS...NORTHWEST CUBA AND JUST NORTH OF THE YUCATAN
PENINSULA. BY THURSDAY EVENING THE FRONT IS FORECAST ACROSS THE
NORTH-CENTRAL BAHAMAS...NORTH-CENTRAL CUBA AND CENTRAL QUINTANA
ROO. NOTE THAT A NEW STRENGTHENING OF A POLAR HIGH IN THE US
PLAINS ON THURSDAY WILL YIELD TO A STRENGTHENING OF THE
NORTHEASTERLY WINDS ACROSS NORTHERN PORTIONS OF THE BASIN TO FAVOR
NEW SOUTHWARD ACCELERATION OF THE SURFACE FRONT AS THE WEEKEND
APPROACHES. GIVEN LIMITED AMOUNTS OF AVAILABLE MOISTURE...EXPECT
LITTLE IMPACT ON PRECIPITATION ON TUESDAY AND WEDNESDAY. YET ON
THURSDAY...THE FRONT IS EXPECTED TO INTERACT WITH A MOIST PLUME IN
THE GULF OF HONDURAS TO SUSTAIN MAXIMA OF 15-30MM FROM SOUTHERN
QUINTANA ROO INTO BELIZE. FURTHER WEST ACROSS THE CARIBBEAN BASIN
OF GUATEMALA INTO SOUTHERN VERACRUZ...NORTHEASTERLY LOW-LEVEL
WINDS WILL INTERACT WITH OROGRAPHY TO SUSTAIN SIMILAR ACCUMULATION
FROM THURSDAY THROUGH FRIDAY MORNING.
SHEAR LINE IN THE ATLANTIC: A POTENT LOW FAR IN THE NORTH ATLANTIC
CONTINUES TO SUSTAIN AN ELONGATED SHEAR LINE THAT EXTENDS INTO
TRINIDAD ON TUESDAY...WHERE IT IS HIGHLIGHTING PRECIPITATION. BY
WEDNESDAY EVENING EXPECT THE SHEAR LINE TO EXTEND INTO THE ORINOCO
DELTA...AND BACK INTO TRINIDAD BY THURSDAY EVENING. ON TUESDAY AND
WEDNESDAY...EXPECT MAXIMA GENERALLY IN THE 15-25MM/DAY RANGE. YET
ON THURSDAY...THE ARRIVAL OF A MOIST PLUME FROM THE TROPICAL
ATLANTIC AND INCREASINGLY UPPER DIVERGENT CONDITIONS ASSOCIATED
WITH THE SUBEQUATORIAL RIDGE WILL FAVOR AN INCREASE IN
ACCUMULATION. EXPECT MAXIMA INCREASING TO 20-40MM/DAY FROM
TRINIDAD AND TOBAGO INTO NORTHERN GUYANA.
CENTRAL AMERICA: A MOIST PLUME HAS BREWED IN THE TAIL OR WESTERN
END OF THE SHEAR LINE...ACROSS THE SOUTH-CENTRAL CARIBBEAN. THIS
PLUME OF PRECIPITABLE WATER VALUES EXCEEDING 50MM IS ENTERING
CENTRAL AMERICA ON TUESDAY. THIS WILL SUSTAIN AN UNSEASONABLY WET
PATTERN FOR PORTIONS OF CENTRAL AND NORTHERN CENTRAL AMERICA
THROUGH THE FORECAST CYCLE. THROUGH EARLY WEDNESDAY EXPECT MAXIMA
OF 15-25MM IN EASTERN NICARAGUA AND ADJACENT CARIBBEAN ISLANDS. ON
WEDNESDAY EXPECT SIMILAR AMOUNTS SPREADING INTO EASTERN COSTA RICA
AND NORTHEAST HONDURAS. IN EASTERN GUATEMALA AND BELIZE/SOUTHERN
QUINTANA ROO EXPECT MAXIMA OF 20-35MM. ON THURSDAY...EXPECT MAXIMA
OF 20-35MM FROM WEST PANAMA INTO NORTHEAST HONDURAS...AND ALONG
THE NORTH COAST OF HONDURAS INTO EASTERN GUATEMALA.
NORTHERN SOUTH AMERICA: IN THE UPPER LEVELS...A POTENT
SUBEQUATORIAL JET EXTENDS FROM THE EQUATORIAL PACIFIC JUST SOUTH
OF THE GALAPAGOS ISLANDS...ACROSS ECUADOR...SOUTHERN COLOMBIA INTO
SOUTHEASTERN VENEZUELA. TYPICALLY...THIS FAVORS ENHANCED UPPER
CONVERGENCE AND LIMITS POTENTIAL RAINFALL ACCUMULATIONS IN THE
REGION. MODELS AGREE ON THE BOLIVIAN HIGH STRENGTHENING
SIGNIFICANTLY THROUGH THURSDAY....WHICH WILL YIELD TO THE
EXPANSION OF DIVERGENT SOUTHEASTERLY FLOW IN THE UPPER LEVELS
ACROSS NORTHERN SOUTH AMERICA. THIS SIGNIFIES A MORE FAVORABLE
ENVIRONMENT FOR DEEP CONVECTION AND HIGHER RAINFALL ACCUMULATIONS.
THE LARGEST ACCUMULATIONS ARE EXPECTED GENERALLY ALONG AND SOUTH
OF THE NET...FORECAST TO EXTEND GENERALLY FROM SOUTHERN GUYANA
INTO NORTHERN PERU AND EASTERN ECUADOR. EAST OF THE ANDES...EXPECT
MAXIMA ABOVE THE 20-35MM/DAY RANGE TO EXPAND NORTHWESTWARD AS THE
CYCLE PROGRESSES...REACHING AREAS AS FAR NORTH AS SOUTH-CENTRAL
VENEZUELA SOUTH-CENTRAL COLOMBIA. EXPECT ALSO AN INCREASING TREND
TO MAXIMA OF 20-45MM IN SOUTH-CENTRAL COLOMBIA AND NORTHERN PERU
BY THURSDAY. WEST OF THE ANDES...LONG-FETCH MOIST WESTERLIES WILL
SUSTAIN WET CONDITIONS FROM NORTHWEST ECUADOR INTO CENTRAL
COLOMBIA DUE TO CONTINUED ENHANCED MOISTURE CONVERGENCE. EXPECT
MAXIMA OF 25-50MM/DAY THROUGH THE CYCLE...ALTHOUGH LESSER AMOUNTS
ARE POSSIBLE ON WEDNESDAY.
TINOCO...(WPC)
GALVEZ...(WPC)
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