002
FXCA20 KWBC 131633
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1132 AM EST WED DEC 13 2023
NOTE: PERSISTENT ROUNDS OF MODERATE TO LOCALLY HEAVY RAINFALL ARE
EXPECTED ACROSS THE NORTHWEST BAHAMAS IN ASSOCIATION WITH
STATIONARY SURFACE BOUNDARY AND INTERACTION WITH UPPER TROUGHS.
EXPECT THE HEAVIEST ON WEDNESDAY...AND ANOTHER PEAK BY SATURDAY AS
A NEW UPPER TROUGH AND AN EXTRA TROPICAL CYCLONE FORECAST TO FORM
OVER THE GULF OPF MEXICO MEANDER NORTHEASTWARD. THIS WILL FAVOR
FOUR DAY ACCUMULATION OF 4-6 INCHES IN BIMINI AND 2 TO 4 INCHES IN
THE REST OF THE NORTHWEST BAHAMAS.
FORECAST BULLETIN 13 DEC 2023 AT 1700 UTC: A SURFACE FRONT IS
BECOMING STATIONARY ACROSS THE NORTHERN BAHAMAS...WHERE IT IS
FORECAST TO PERSIST OVER SEVERAL DAYS FAVORING PERSISTENT
PRECIPITATION. ON WEDNESDAY EVENING THE FRONT IS FORECAST ACROSS
THE FAR NORTHWEST BAHAMAS...SOUTH FLORIDA...25N 90W...NORTHERN
TAMAULIPAS/NUEVO LEON. BY THURSDAY EVENING EXPECT THE FRONT ACROSS
ELEUTHERA/NEW PROVIDENCE...FLORIDA KEYS...INTO SOUTH TEXAS. ON
FRIDAY...CYCLOGENESIS IS EXPECTED IN SOUTHWEST PORTIONS OF THE
GULF OF MEXICO. THIS WILL FORM A LOW...FORECAST TO INTERACT WITH
THE SURFACE FRONT. BY FRIDAY EVENING EXPECT THE FRONT ACROSS THE
NORTHWEST BAHAMAS...FLORIDA KEYS...INTO 25N 92W. A WEAKENING SHEAR
LINE IS ALSO PRESENT. BY WEDNESDAY EVENING EXPECT IT ALONG THE
NORTHWEST BAHAMAS...THE NORTHWEST COAST OF CUBA...NORTHEAST
YUCATAN PENINSULA. IN THE BAHAMAS...THE FRONT WILL FAVOR
15-30MM/DAY AND MAXIMA OF 40-80MM ON WEDNESDAY. ON THURSDAY EXPECT
10-15MM/DAY AND MAXIMA OF 20-40MM. ON FRIDAY THIS DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-30MM. IN AREAS WEST AND ON
WEDNESDAY...THE FRONT WILL FAVOR MAXIMA OF 15-25MM IN NORTHEAST
MEXICO...WHILE THE SHEAR LINE FAVORS MAXIMA OF 25-50MM ALONG
BELIZE AND EASTERN PORTIONS OF THE YUCATAN PENINSULA.
A MID-LEVEL RIDGE CENTERS NEAR BERMUDA BUT EXTENDS ITS INFLUENCE
INTO THE GREATER ANTILLES. ALTHOUGH THIS WILL FAVOR A PERSISTENT
TRADE WIND CAP AND LIMIT AVAILABLE MOISTURE...STRONG 20-35KT
EAST-NORTHEASTERLY TRADES ARE FORECAST FROM THE LEEWARD ISLANDS
INTO SOUTHEAST CUBA ON WEDNESDAY...DECREASING GRADUALLY THROUGH
FRIDAY. THESE WILL NOT ONLY FAVOR A SHALLOW COLD ADVECTIVE WEATHER
PATTERN HIGHLGHTING SHALLOW INSTABILITY AND TRADE WIND SHOWERS.
THEY WILL ALSO ENHANCE THE EXTRACTION OF MOISTURE FROM THE OCEAN
AND HIGHLIGHT MOISTURE CONVERGENCE IN NORTHERN AND EASTERN SLOPES
AND COASTAL AREAS. THE LARGEST ACCUMULATIONS ARE EXPECTED IN
HISPANIOLA AND PUERTO RICO WHERE EXPECT MAXIMA OF 15MM ON
WEDNESDAY INCREASING TO MAXIMA OF 15-30MM BY FRIDAY.
CYCLOGENESIS IS OCCURRING IN THE TROPICAL NORTH ATLANTIC. THIS IS
ORGANIZING A SURFACE FRONT WELL TO THE SOUTH OF USUAL POSITIONS.
GIVEN A WEAK THERMAL BOUNDARY ASSOCIATED WITH THIS SYSTEM...IT IS
BEING ANALYZED AS A FRONTAL SHEAR LINE ACROSS THE WINDWARD
ISLANDS. ON WEDNESDAY EVENING EXPECT THE SHEAR LINE ACROSS
TRINIDAD INTO NORTHEAST VENEZUELA. BY WEDNESDAY EVENING EXPECT IT
ACROSS TOBAGO...NORTHERN TRINIDAD...ISLA MARGARITA. IT IS FORECAST
TO THEN MEANDER NORTHWARD AND BY FRIDAY EVENING IT IS EXPECTED
ALONG BARBADOS AND THE GRENADINES. THIS WILL FAVOR SCATTERED
THUNDERSTORMS WITH MAXIMA OF 15-30MM ON WEDNESDAY...MAXIMA OF
15-25MM ON THURSDAY...AND 05-10MM/DAY AND MAXIMA OF 15-30MM ON
FRIDAY.
A STRENGTHENING UPPER RIDGE OVER THE EASTERN PACIFIC IS LEADING TO
NORTHWESTERLY MID-UPPER FLOW ACROSS WESTERN CENTRAL AMERICA. THE
ASSOCIATED COOLING IS RESULTING IN THE AMPLIFICATION OF AN UPPER
TROUGH TO THE EAST. BY WEDNESDAY EVENING EXPECT THE TROUGH ALONG
THE CAYMAN ISLANDS...WEST PANAMA...NORTHERN ECUADOR. BY THURSDAY
EVENING EXPECT IT ALONG THE HAITIAN PENINSULA...WEST PANAMA. BY
FRIDAY THE TROUGH IS FORECAST ALONG THE NORTHER COAST OF COLOMBIA
INTO A LOW NEAR 03N 81W. THE TROUGH IS FORECAST TO ESTABLISH A
PERSISTENT UPPER DIVERGENT TIER OVER THE GULF OF PANAMA AND
NORTHWEST COLOMBIA ON WEDNESDAY EVENING...FORECAST TO PERSIST OVER
COLOMBIA THROUGH EARLY SATURDAY. THIS WILL NOT ONLY STIMULATE
ASCENT AND THE INCREASE IN DEEP CONVECTION...BUT WILL AID WITH THE
TRANSPORT OF A MOISTER AIR MASS FROM THE SOUTH. THE RESULT IS AN
INCREASING TREND IN THE COVERAGE AND INTENSITY OF PRECIPITATION IN
COLOMBIA. ON WEDNESDAY EXPECT MAXIMA OF 20-35MM/DAY IN MOST OF
WESTERN COLOMBIA. ON THURSDAY THIS INCREASES TO MAXIMA OF 30-60MM
FROM NORTHWEST ECUADOR INTO THE NORTHERN CHOCO...WHILE IN CENTRAL
COLOMBIA EXPECT MAXIMA OF 15-20MM. BY FRIDAY...EXPECT MAXIMA OF
75-125MM IN CENTRAL WESTERN COLOMBIA. ACROSS CENTRAL COLOMBIA
ACROSS THE ANDEAN REGION AND MAGDALENA MEDIO EXPECT 15-20MM/DAY
AND MAXIMA OF 25-50MM.
ELSEWHERE IN NORTHERN SOUTH AMERICA...THE MOST ACTIVE CONVECTION
AND LARGEST PRECIPITATION AMOUNTS ARE FORECAST TO CLUSTER IN THE
WESTERN AMAZON GIVEN LIMITED AMOUNTS OF AVAILABLE MOISTURE AND
SUBSIDENCE IN THE GUIANAS AND EASTERN AMAZON REGIONS.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
NONE
GALVEZ...WPC (USA)
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