921
FXCA20 KWBC 071831
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EST THU DEC 07 2023
FORECAST BULLETIN 07 DEC 2023 AT 1830 UTC: AN UPPER TROUGH LOCATED
WEST OF MEXICO IS HIGHLIGHTING UPPER DIVERGENCE ACROSS SOUTHWEST
AND CENTRAL MEXICO. GIVEN THE PRESENCE OF PRECIPITABLE WATER IN
THE 35-45MM RANGE OFF THE COAST OF SOUTHWEST MEXICO...AVAILABLE
MOISTURE IS SUFFICIENT TO FAVOR SCATTERED PRECIPITATION. THROUGH
EARLY FRIDAY EXPECT SCATTERED ACCUMULATION OF 05-10MM/DAY AND
MAXIMA OF 15MM IN CENTRAL AND SOUTHWEST MEXICO. THIS DECREASES
THEREAFTER.
AN ELONGATED FRONT EXTENDS FROM THE NORTH ATLANTIC INTO THE
GREATER ANTILLES ON THURSDAY. BY THURSDAY EVENING IT IS EXPECTED
ALONG 23N 60W...NORTHERN HISPANIOLA...NORTHERN JAMAICA...ISLAS DE
LA BAHIA/NORTHWEST HONDURAS. BY FRIDAY EVENING IT IS EXPECTED
ALONG 22N 60W...INAGUA...CENTRAL CUBA...YUCATAN CHANNEL. BY
SATURDAY EVENING IT IS EXPECTED ALONG 20N 60W...TURKS AND
CAICOS...CENTRAL BAHAMAS. A PREFRONTAL SHEAR LINE IS ALSO PRESENT
AND BY THURSDAY EVENING IT IS FORECAST ALONG THE SOUTHEAST
DOMINICAN REPUBLIC...NORTHEAST NICARAGUA. BY FRIDAY EVENING EXPECT
A WEAKENING SYSTEM ALONG THE NORTHEAST DOMINICAN
REPUBLIC...JAMAICA...NORTHERN BELIZE. IT IS THEN FORECAST TO
DISSIPATE.BOTH FRONT AND SHEAR LINE WILL HIGHLIGHT PRECIPITATION
PARTICULARLY IN REGIONS OF TERRAIN ENHANCEMENT. GIVEN THE
STABILIZING IMPACT OF A MID-LEVEL RIDGE...FORECAST TO BUILD OVER
THE GREATER ANTILLES AND ALL OF THE NORTHERN CARIBBEAN THROUGH THE
CYCLE...EXPECT MOST CONVECTION WITH THESE SYSTEMS TO REMAIN
SHALLOW AND PRODUCE CONSERVATIVE RAINFALL AMOUNTS. AN EXCEPTION IS
NORTHERN HONDURAS/CENTRAL GUATEMALA EARLY IN THE CYCLE...WHERE
EXPECT MAXIMA OF 30-60MM IN THUNDERSTORMS ON THURSDAY...GIVEN
ENHANCEMENT BY TERRAIN. ALSO ON THURSDAY...EXPECT MAXIMA OF
20-35MM IN JAMAICA AND IN NORTHERN HISPANIOLA. SIMILAR AMOUNTS ARE
EXPECTED IN NORTHEAST NICARAGUA/EASTERN HONDURAS WITH THE SHEAR
LINE. ON FRIDAY EXPECT MAXIMA OF 20-40MM IN THE NORTHEAST
DOMINICAN REPUBLIC WITH THE SHEAR LINW. IN NORTH HAITI/SOUTHEAST
CUBA EXPECT MAXIMA OF 15-25MM...AND MAXIMA OF 15-20MM IN JAMAICA.
IN BELIZE AND QUINTANA ROO...SHEAR LINE CONVERGENCE WILL FAVOR
MAXIMA OF 15-20MM. ON SATURDAY EXPECT MAXIMA OF 15MM IN THE
SOUTHEAST BAHAMAS AND TURKS AND CAICOS.
A POTENT FRONT IS EXPECTED TO ENTER NORTHERN MEXICO EARLY ON
SATURDAY. BY SATURDAY EVENING IT IS EXPECTED ALONG SOUTH
TEXAS...CENTRAL COAHUILA...SOUTHERN CHIHUAHUA. EXPECT LIMITED
EFFECTS ON PRECIPITATION AT LEAST ON SATURDAY...GIVEN LIMITED
AMOUNTS OF AVAILABLE MOISTURE.
A SYSTEM OF INTEREST IS A MOIST PLUME THAT HAS HAS BEEN DRAWN FROM
THE EQUATORIAL ATLANTIC INTO THE SOUTHEAST CARIBBEAN BY THE UPPER
TROUGH LOCATED NEAR AND EAST OF THE WINDWARD ISLANDS. THE UPPER
TROUGH ASSOCIATES WITH A MID-LEVEL LOW THAT CENTERS NEAR THE
FRENCH ANTILLES. ALTHOUGH THE MID-LEVEL LOW IS FORECAST TO
FILL...AN UPPER TROUGH PROPAGATING FROM WEST TO EAST ON THURSDAY
AND FRIDAY WILL PROVIDE MARGINAL ENHANCEMENT TO CONVECTION
DEVELOPING IN ASSOCIATION WITH THE MOIST PLUME. ON THURSDAY EXPECT
MAXIMA OF 20-40MM IN THE WINDWARD ISLANDS AND TRINIDAD AND TOBAGO.
IN THE ABC ISLANDS AND IN THE CENTRAL LESSER ANTILLES EXPECT
MAXIMA OF 15-30MM. ON FRIDAY...AS ASCENT INDUCED BY THE UPPER
TROUGH PEAKS...EXPECT A PEAK IN PRECIPITATION IN THE WINDWARD
ISLANDS WHERE AMOUNTS ARE FORECAST IN THE 15-20MM/DAY AND MAXIMA
OF 30-60MM RANGE. IN THE CENTRAL LESSER ANTILLES EXPECT MAXIMA OF
20-45MM...WHILE IN THE ABC...THE MOIST PLUME WILL FAVOR MAXIMA OF
15-20MM. ON SATURDAY...EXPECT THE LINGERING MOIST PLUME TO FAVOR
MAXIMA OF 20-35MM IN TRINIDAD AND TOBAGO AND NORTHEAST
VENEZUELA...WHEREAS IN THE ABC AND NORTHERN VENEZUELA EXPECT
05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM.
IN SOUTHERN CENTRAL AMERICA...EXPECT GENERALLY FAIR WEATHER
CONDITIONS EXCEPT IN REGIONS OF TRADE WIND CONVERGENCE IN THE
CARIBBEAN BASIN. A WIDESPREAD ACCELERATION OF THE EASTERLY TRADES
ON SATURDAY WILL FAVOR A NOTICEABLE INCREASE IN RAINFALL AMOUNTS
IN SOUTHEAST NICARAGUA AND NORTHEAST COSTA RICA...WHERE EXPECT
MAXIMA INCREASING TO 20-45MM.
IN NORTHERN SOUTH AMERICA...THE PACIFIC ITCZ IS FORECAST TO
MEANDER NORTH...YIELDING TO A DECREASE IN RAINFALL AMOUNTS IN THE
PACIFIC BASIN OF ECUADOR AFTER THURSDAY...WHEN EXPECT MAXIMA OF
25-50MM. TO THE EAST...EXPECT SEASONABLY WET CONDITIONS IN MOST OF
VENEZUELA DUE TO THE PRESENCE OF THE AFOREMENTIONED MOIST PLUME.
THIS WILL FAVOR MAXIMA OF 20-35MM IN MOST OF SOUTHERN AND EASTERN
VENEZUELA ON THUSDAY...WHILE IN NORTHERN VENEZUELA EXPECT MAXIMA
OF 15MM. ON FRIDAY EXPECT MAXIMA OF 30-60MM IN SOUTHERN VENEZUELA
AND NORTHWEST BRASIL...WHILE ELSEWHERE IN VENEZUELA EXPECT
SCATTERED AMOUNTS IN THE 05-10MM/DAY AND ISOLATED MAXIMA OF
15-25MM RANGE. ON SATURDAY...EXPECT A DRYING TREND ESTABILISHING
ACROSS CENTRAL VENEZUELA/ORINOQUIA AS THE LOW-LEVEL JET REFORMS.
THIS WILL LIMIT THE LARGEST ACCUMULATIONS TO SOUTHERN VENEZUELA
AND MOST OF THE COLOMBIAN ORINOQUIA...WHERE EXPECT MAXIMA OF
20-35MM.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
NONE
GALVEZ...WPC (USA)
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