878
FXCA20 KWBC 202107
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
406 PM EST WED DEC 20 2023
FORECAST BULLETIN 20 DEC 2023 AT 1930 UTC: UNDER THE INFLUENCE OF
AN AMPLIFIED TRAIN OF UPPER TROUGHS AND RIDGES IN THE
WESTERLIES...SEVERAL BOUNDARIES ARE PRESENT IN THE BASIN. ON
WEDNESDAY...THE MOST PROMINENT BOUNDARY IS A FRONT THAT EXTENDS
ACROSS HISPANIOLA...PROVIDENCIA AND SAN ANDRES. ON THURSDAY...THE
NORTHERN TIER OF THIS FRONT IS FORECAST TO MERGE WITH ANOTHER
FRONT ARRIVING FROM THE NORTH. BY THURSDAY EVENING EXPECT THE
BOUNDARY ALONG 20N64W...CENTRAL HIAPANIOLA...CAYMAN BRAC...FAR
WEST CUBA...SOUTH TEXAS. BY FRIDAY EVENING EXPECT THE FRONT JUST
NORTH OF PUERTO RICO...SOUTHERN HISPANIOLA...FAR SOUTHEAST
CUBA...INTO A STATIONARY BOUNDARY ACROSS PINAR DEL RIO AND INTO
SOUTH TEXAS. THE SOUTHERN TIER OF THE FRONT IS FORECAST TO LOOSE
SOME BAROCLINICITY THROUGH THURSDAY...EVOLVING INTO A FRONTAL
SHEAR LINE OR VERY LOW BAROCLINICITY FRONT. BY THURSDAY EVENING
EXPECTED ALONG BARAHONA...16N 80W...NORTHEAST COSTA RICA. BY
FRIDAY EVENING EXPECT JUST SOUTH OF JAMAICA...SOUTHEAST NICARAGUA.
ON WEDNESDAY...EXPECT MAXIMA OF 25-50MM IN NORTHEAST
HISPANIOLA...WHILE IN THE CARIBBAN BASIN OF PANAMA AND COSTA RICA
AS WELL AS SAN ANDRES AND PROVIDENCIA EXPECT MAXIMA OF 15-30MM. ON
THURSDAY EXPECT MAXIMA OF 25-50MM IN NORTHERN AND NORTHEAST
HISPANIOLA. IN THE CARIBBEAN BASIN OF COSTA RICA EXPECT MAXIMA OF
25-50MM....AND IN SAN ANDRES AND PROVIDENCIA EXPECT MAXIMA OF
15-30MM. ON FRIDAY EXPECT MAXIMA OF 20-45MM IN NORTHERN COSTA RICA
AND SOUTHEAST NICARAGUA...AND MAXIMA OF 15-25MM IN SAN ANDRES AND
PROVIDENCIA. IN THE NORTHEAST DOMINICAN REPUBLCI EXPECT MAXIMA OF
15-25MM...AND MAXIMA OF 15MM IN PUERTO RICO.
A POTENT UPPER TROUGH AND ASSOCIATED FRONT IS FORECAST TO MOVE
INTO NORTHWEST MEXICO ON THURSDAY. ALTHOUGH THE FRONT IS FORECAST
TO ENTER EARLY ON FRIDAY TO EXTEND ACROSS EASTERN SONORA...CENTRAL
BAJA CALIFORNIA BY FRIDAY EVENING...HEAVY RAIN IS EXPECTED TO
DEVELOP AS EARLY AS THURSDAY EVENING IN NORTHERN PORTIONS OF BAJA
CALIFORNIA...AS MOIST INFLOW FROM THE SOUTH INTERACTS WITH THE
SIERRA SAN PEDRO MARTIR. THIS WILL FAVOR AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 25-50MM. ON FRIDAY...EXPECT THE HEAVIEST
PRECIPITATION IN NORTHERN SONORA WHERE AMOUNTS ARE FORECAST TO
REACH 10-15MM/DAY AND MAXIMA OF 20-45MM WITH A MARGINAL RISK FOR
SEVERE WEATHER. IN NORTHERN BAJA CALIFORNIA EXPECT MAXIMA OF
15-30MM.
A FRONTAL SHEAR LINE IS WEAKENING ACROSS THE WINDWARD ISLANDS. BY
WEDNESDAY EVENING EXPECT IT ACROSS BARBADOS...THE GRENADINES INTO
THE ABC ISLANDS. BY THURSDAY EVENING EXPECT IT ACROSS SAINT
LUCIA...THE ABC ISLANDS TO THEN DISSIPATE. THIS WILL FAVOR MAXIMA
OF 15MM IN THE WINDWARD ISLANDS AND LIGHTER AMOUNTS IN THE ABC
ISLANDS ON WEDNESDAY...AND MAXIMA OF 15MM IN THE WINDWARD ISLANDS
AND ABC ISLANDS ON THURSDAY BEFORE DISSIPATING.
IN NORTHERN SOUTH AMERICA...THE MOST ACTIVE CONVECTION IS EXPECTED
IN THE AMAZON BASIN AS VENTILATION INCREASES IN RESPONSE TO A
REORGANIZATION OF THE BOLIVIAN HIGH. HOWEVER...NOTE THAT
ACCUMULATIONS ARE EXPECTED TO INCREASE THROUGH FRIDAY AND THE
WEEKEND IN AMAPA AND FRENCH GUIANA...GIVEN A GRADUAL REACTIVATION
OF CONVECTION IN THE ATLANTIC ITCZ PARTIALLY IN RESPONSE TO THE
ACTIVE MJO.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
NONE
GALVEZ...WPC (USA)
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