104
FXCA20 KWBC 231859
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 PM EST THU JAN 23 2025
FORECAST BULLETIN 23 JANUARY 2025 AT 19:00 UTC
OF INTEREST IN THE FORECAST CYCLE IS A PERSISTENT FRONT IN
NORTHERN PORTIONS OF THE BASIN...WHICH ASSOCIATES WITH THE COLD
AIR OUTBREAK IN THE UNITED STATES. BY THURSDAY EVENING EXPECT A
STATIONARY BOUNDARY ACROSS THE FAR NORTHWEST BAHAMAS...WEST CUBA
INTO NORTHERN BELIZE. A STRENGTHENING OF A POLAR HIGH IN THE
SOUTHERN USA WILL FAVOR AN INCREASE IN THE NORTHERLY WINDS ON
FRIDAY MORNING TO PUSH THE BOUNDARY SOUTHWARD. BY FRIDAY EVENING
EXPECT THE FRONT ACROSS THE NORTHWEST BAHAMAS...WHILE THE OLD
BOUNDARY STARTS TO WEAKEN ACROSS CENTRAL CUBA...THE CAYMAN SILANDS
INTO THE SOUTHERN GULF OF HONDURAS. A NEW BOUNDARY IS EXPECTED TO
ORGANIZE AND BY FRIDAY EVENING IT IS FORECAST ACROSS WEST CUBA
INTO SOUTHERN QUINTANA ROO. BY SATURDAY EVENING EXPECT A COLD
FRONT ACROSS THE CENTRAL BAHAMAS...INTO A WEAKENING COLD FRONT
ACROSS CENTRAL CUBA...WEST CAYMAN AND NORTHEAST HONDURAS. THE
LARGEST RAINFALL ACCUMULATION WITH THIS SYSTEM IS EXPECTED IN
WESTERN PORTIONS OF THE GULF OF HONDURAS DUE TO ENHANCED LOW-LEVEL
MOISTURE CONVERGENCE THROUGH THE FORECAST CYCLE. THROUGH EARLY
FRIDAY EXPECT MAXIMA OF 25 - 50MM FROM SOUTHERN QUINTANA ROO INTO
NORTHWEST HONDURAS. THIS INCREASES TO MAXIMA OF 50 - 100MM BY
FRIDAY INTO EARLY SATURDAY. BY SATURDAY INTO EARLY SUNDAY EXPECT
SIMILAR AMOUNTS IN FAR SOUTHERN BELIZE...EAST-CENTRAL GUATEMALA
AND NORTHWEST HONDURAS. NORTHERLY FLOW INTO SOUTHERN MEXICO WILL
ALSO FAVOR MODERATE AMOUNTS IN SOUTHERN VERACRUZ/NORTHWEST CHIAPAS
AND TABASCO DUE TO TERRAIN ENHANCEMENT. PRECIPITATION IS TO PEAK
ON FRIDAY THROUGH EARLY SATURDAY WHEN EXPECT MAXIMA IN THE 15 -
30MM/DAY RANGE.
A SHEAR LINE IS ALSO EXPECTED WITH THIS EVOLUTION. BY FRIDAY
EVENING EXPECT IT TO FORM FROM FAR SOUTHEAST CUBA ACROSS FAR
SOUTHEAST JAMAICA INTO NORTHERN COSTA RICA. INITIALLY THIS WILL
HAVE LIMITED IMPACTS ON PRECIPITATION...TO FAVOR MAXIMA OF 10MM IN
NORTHEAST JAMAICA AND MAXIMA OF 20 - 35MM IN NORTHERN COSTA RICA.
ON SATURDAY THROUGH EARLY SUNDAY EXPECT MAXIMA OF 15 - 30MM
DEVELOPING IN THE BLUE MOUNTAINS OF JAMAICA...WHILE IN NORTHERN
COSTA RICA AND SOUTHEAST NICARAGUA EXPECT MAXIMA OF 20- - 40MM. IN
NORTHEAST NICARAGUA...SHEAR LINE DONVECTION WILL FAVOR MAXIMA OF
15 - 30MM.
THE EASTERN CARIBBEAN WILL CONTINUE TO BE UNDER THE INFLUENCE OF A
MID-LEVEL RIDGE CENTERINT WELL TO THE NORTHEAST OF THE LEEWARD
ISLANDS...BUT EXTENDING PERSISTENTLY OVER MOST OF THE CARIBBEAN
THROUGH THE FORECAST CYCLE. MORE THAN STABILITY...THE FACTOR THAT
WILL PLAY A STRONGER ROLE IN LIMITING PRECIPITATION AMOUNTS WILL
CONTINUE TO BE VERY DRY AIR LOCATED ABOVE THE MARINE LAYER. SOME
MODELS ARE EVEN SHOWING RELATIVE HUMIDITY VALUES BELOW 5% AT 700
HPA DURING EXTENDED PERIODS OF THE FORECAST CYCLE. ANY ACTIVITY
WILL ASSOCIATE WITH ENHANCED MOISTURE CONVERGENCE IN EASTERN
SLOPWS...ASSOCIATED WITH THE ACCELERATED EASTERLY
TRADES...PRIMARILY CLUSTERING IN STEEP TERRAIN OF THE CENTRAL
LESSER ANTILLES.
IN NORTHERN SOUTH AMERICA...THE MOST ACTIVE PRECIPITATION IS
EXPECTED IN THE NORTHERN GUIANAS ASSOCIATED WITH A RI9SK OF ECHO
TRAINING ALONG AN ACTIVE ATLANTIC ITCZ INTERACTING WITH THE COAST.
THIS WILL FAVOR MAXIMA OF 35 - 70MM THROUGH EARLY FRIDAY
DECREASING TO MAXIMA OF 30 - 60MM BY FRIDAY INTO EARLY SATURDAY.
GALVEZ...(WPC)
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