905
FXCA20 KWBC 301805
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
105 PM EST THU JAN 30 2025


FORECAST BULLETIN 30 JANUARY 2025 AT 17:30 UTC

...LARGE SCALE CONDITIONS...

MJO:
THE MJO SIGNAL HAS STRENGTHENED CONSIDERABLY AND IS CURRENTLY
APPROACHING PHASE 4 THIS WEEK AND EARLY FEBRUARY. THIS  MJO PHASE
GENERALLY FAVORS UPPER CONVERGENCE AND  DRIER CONDITIONS IN THE
CARIBBEAN BASIN. HOWEVER AS THIS MJO REACHES PHASE 4 IS EXPECTED
TO BE  SLIGHTLY LESS ORGANIZED. UNCERTAINTIES REMAINS IN THE
MODELS ABOUT THE ORGANIZATION OF THE MJO.

KELVIN WAVE:
NONE SIGNIFICANT KELVIN WAVE APPROACHING THE CARIBBEAN BASIN BY
THE END OF THE WEEK.

ENSO CONDITIONS:
LA NINA


...SYNOPTIC CONDITIONS CARIBBEAN BASIN...

UPPER LEVELS:
AN UPPER LEVEL TROUGH CONTINUES PROPAGATING EASTWARD OVER THE
WESTERN PLAINS OF THE USA. THE TROUGH WILL BE LOCATED NEAR THE
SOUTHEAST OF USA TODAY.

WHILE A STRONG UPPER RIDGE WILL BUILD OVER THE WESTERN CARIBBEAN
FROM TODAY INTO FRIDAY...THIS WILL FAVOR STABLE CONDITIONS AND
WILL HINDER THE DEVELOPMENT OF DEEP CONVENTION OVER THE GREATER
AND LESSER ANTILLES. BY FRIDAY AN UPPER LEVEL TROUGH WILL AMPLIFY
TO THE EAST OF THE LESSER ANTILLES...WITH LIMITED IMPACT IN THE
CARIBBEAN AND TROPICAL SOUTH AMERICA. FURTHER THIS RIDGE WILL
FAVOR THE INTENSITY OF THE TRADE WIND OVER THE CARIBBEAN. THOSE
CONDITIONS ARE TYPICAL OF LA NINA AND DURING THIS TIME OF THE YEAR.

LOWER LEVELS:
BY FRIDAY A COLD FRONT OVER FLORIDA WILL EXTEND INTO VERACRUZ AND
AN INDUCED TROUGH WITH LIMITED IMPACT OVER THE COAST OF MEXICO.
ANOTHER COLD FRONT WILL CONTINUE PROPAGATING INTO THE NORTHERN
CARIBBEAN STARTING TODAY AND IS EXPECTED TO EXIT INTO THE CENTRAL
ATLANTIC BY FRIDAY. AN INDUCED TROUGH IN COMBINATION WITH A
SHALLOW MOISTURE PLUME AND LOCAL DIURNAL HEATING THROUGH THE NEXT
FORECAST CYCLE WILL PROMOTE SOME SHALLOW CONVECTION OVER THE
GREATER ANTILLES FROM FRIDAY INTO SATURDAY.


...PRECIPITATION IN THE CARIBBEAN...
AS MENTIONED BEFORE THE UPPER CONVERGENCE AND MID-LEVEL DRY AIR
WILL LIMIT THE DEVELOPMENT OF PRECIPITATION ACCUMULATIONS. HOWEVER
SHALLOW MOIST PLUMES ARE EXPECTED TO MOVE WESTWARD ACROSS THE
GREATER AND LESSER ANTILLES. MOIST PLUME-TERRAIN INTERACTIONS WILL
FAVOR THE DEVELOPMENT OF THE FOLLOWING ISOLATED MAXIMA:

LESSER ANTILLES: MAXIMA OF 15 - 20MM ON FRIDAY AND SATURDAY.THIS
IS DUE TO THE TRASNPORT OF MOISTURE TO THE REGION BY A LOW LEVEL
JET TO THE EAST OF THE LESSER ANTILLES.
PUERTO RICO: MAXIMA OF 10MM ON THURSDAY...FRIDAY AND SATURDAY. THE
PEAK WILL ON THURSDAY WHEN THE MOSTURE PLUME IS APPROACHING THE
ISLAND.
DOMINICAN REPUBLIC: MAXIMA OF 10 -15MM ON THURSDAY...FRIDAY AND
SATURDAY. THE PEAK WILL ON FRIDAY WHEN A SHALLOW MOSUTRE PLUME IS
MOVE THROUGH THE REGION.
EASTERN CUBA: MAXIMA OF 10 -15MM ON THURSDAY AND FRIDAY.
JAMAICA: MAXIMA OF 10 - 15MM ON THURSDAY...FRIDAY AND SATURDAY.
THE PEAK WILL BE BY FRIDAY MORNING WHEN THE RELATIVE LARGE
PRECIPITABLE WATER ARRIVES TO THE REGION.

...PRECIPITATION IN MEXICO AND NORTHERN CENTRAL AMERICA...
THE COLD FRONT EXTENDING INTO VERACRUZ AND AN INDUCED TROUGH WILL
CONTRIBUTE OT THE DEVELOPMENT OF SOME SHOWERS. FURTHER...AS
TEHUANTEPEC LOW-LEVEL JET DEVELOPS...THE EXIT PART OF THE JET WILL
PROMOTE SOME SHOWER DEVELOPMENT OVER TABASCO..SOUTHERN VERACRUZ
AND WESTERN CAMPECHE. THEREFORE THE FOLLOWING MAXIMA ARE EXPECTED:

AREAS OF MEXICO...VERACRUZ...TABASCO...NORTHWEST OF CHIAPAS:
MAXIMA OF 20 - 35MM BY FRIDAY.
AREAS OF MEXICO...TABASCO...NORTHERN CHIAPAS...WESTERN CAMPECHE
AND SOUTHERN VERACRUZ: MAXIMA OF 20 - 35MM BY SATURDAY.
AREAS OF MEXICO...YUCATAN: A MAXIMA OF 10MM ON FRIDAY AND SATURDAY.
AREAS OF MEXICO...VERACRUZ...NORTHEASTERN OF OAXACA...PUEBLA: A
MAXIMA OF 15 - 25MM BY SATURDAY.
NORTHERN GUATEMALA AND WESTERN BELIZE: MAXIMA OF 20 - 35MM BY
FRIDAY AND 15 - 25MM BY SATURDAY.

...PRECIPITATION IN CENTRAL AMERICA...
THIS PHASE OF THE MJO OFTEN CONTRIBUTES TO GENERATE A MORE ACTIVE
CARIBBEAN LOW-LEVEL JET... WHICH TRANSPORTS MORE HUMID AIR INTO
THE COAST OF CENTRAL AMERICA...LEADING TO INCREASED PRECIPITATION
OVER THE EASTERN COAST OF CENTRAL AMERICA. THIS IN COMBINATION
WITH THE INTERACTION WITH TOPOGRAPHY CAN FURTHER INFLUENCE
PRECIPITATION PATTERNS IN THE FOLLOWING AREAS:

BELIZE: MAXIMA OF 10 - 15MM ON THURSDAY...FRIDAY AND SATURDAY.
COSTA RICA: ...A MAXIMA INCREASE OF 25 - 50MM ON FRIDAY... A
MAXIMA OF 20 - 35MM ON SATURDAY. THE RAINFALL PEAK IS EXPECTED ON
FRIDAY WHEN A LARGE MOISTURE PLUME MOVE OVER THE REGION.
EASTERN NICARAGUA AND EASTERN OF HONDURAS: MAXIMA OF 15-25MM FOR
THE FORECAST CYCLE. THE PEAK IS EXPECTED ON FRIDAY WITH THE
INCREASE IN THE MOIST PLUME ENTERING THE REGION.
NORTHERN PANAMA: MAXIMA OF 15 - 25MM ON THURSDAY...A MAXIMA
INCREASE OF 25 - 50MM ON FRIDAY... A MAXIMA OF 20 - 35MM ON
SATURDAY.


...SYNOPTIC CONDITIONS OVER TROPICAL SOUTH AMERICA...

UPPER SOUTHWESTERLY FLOW OVER ECUADOR...COLOMBIA... AND
VENEZUELA...WHICH TYPICALLY PROMOTES ENHANCED UPPER DIVERGENCE BY
THURSDAY AND FRIDAY...PROMOTING RAINFALL ACCUMULATION IN THOSE
REGIONS. BY FRIDAY EVENNING INTO SATURDAY...WEAK UPPER SPEEED
CONVERGENCE OF THE UPPER WESTERLY FLOW OVER ECUADOR AND SOUTHER
COLOMBIA WHICH COULD LIMIT DEEP CONVECTION DEVELOPMENT...SOME
ISOLATED THUNRDERSTORMS CAN BE EXPECTED. OVERALL UPER LEVELS SEEMS
TO NOT PROVIDE ENOUGH SUPPORT FOR DEEP CONVECTION. THE ONSHORE
FLOW AT LOWER LEVELS ALONG AND SOUTH OF THE PACIFIC ITCZ WILL
BECOME MORE PERPENDICUALR BY FRIDAY...THIS COULD ENHANCE THE
INCREASE IN MOISTURE OVER ECUADOR AND SOUTHWEST OF COLOMBIA.
THEREFORE...THE FOLLOWING MAXIMA ARE EXPECTED:

CENTRAL COAST OF ECUADOR AND SOUTHWEST COLOMBIA: A MAXIMA OF 20 -
40MM FOR THURSDAY AND SATURRDAY. A PEAK ON FRIDAY WITH A MAXIMA OF
30 - 60MM. HOWEVER... THE MODEL GUIDANCE SUGGEST UNCERTAINTY ON
THE PRECIPIATION AMMOUNT ON THURSDAY AND MORE AGREEMENT IN THE
MODELS BY FRIDAY. FURTHER..IT SEEMS THAT MODEL ARE OVERESTIMATING
THE TOTAL RAINFALL AMOUNTS AND LOCATION.

DRIER CONDITIONS ARE EXPECTED OVER VENEZUELA AND EASTERN COLOMBIA
FOR THIS FORECAST CYCLE DUE TO THE NOCTURNAL LOW-LEVEL JET OVER
THE CENTRAL OF NORTHERN OF TROPICAL SOUTH AMERICA.

IN THE ATLANTIC BASIN...AS THE ITCZ SHIFTS SOUTHWARD... AND
ANOTHER LOW-LEVEL JET WILL BE ENTERING OVER THE GUINAS... INCREASE
THE VERTICAL WIND SHEAR FROM FRIDAY INTO SATURDAY...THIS WILL
HINDER RAINFALL ACCUMULATION.THEREFORE DRIER CONDITIONS ARE
EXPECTED IN GUIANAS AND AMAPA FOR THIS FORECAST CYCLE. THE REST OF
THE TROPICAL SOUTH AMERICA PRECIPITATION MAXIMA WILL BE ALONG THE
NET ITCZ...WITH MAXIMA OF 15-35MM FOR THE FORECAST CYCLE.

LEDESMA...(WPC)
GALVEZ...(WPC














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