299
FXCA20 KWBC 192024
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
323 PM EST MON DEC 19 2022
FORECAST BULLETIN FROM 19 DEC 2022 AT 18 UTC: AN UPPER TROUGH IN
THE WESTERLIES EXTENDS FROM COLORADO INTO CENTRAL BAJA CALIFORNIA
ON MONDAY. AS THIS TROUGH PROPAGATES EASTWARD...IT WILL FAVOR
CYCLOGENESIS OVER EASTERN TEXAS LATER ON MONDAY...TO DEVELOP A
SURFACE FRONT. BY MONDAY EVENING THE FRONT IS FORECAST TO EXTEND
ACROSS THE LOW JUST OFF GALVESTON INTO CENTRAL TAMAULIPAS...ON
TUESDAY EVENING...THE FRONT IS EXPECTED FROM A LOW IN THE ATLANTIC
COAST OF GEORGIA...NORTH-CENTRAL FLORIDA...A LOW NEAR 27N
85W...CENTRAL VERACRUZ...ALONG THE SIERRA MADRE ORIENTAL. ON
WEDNESDAY EVENING EXPECT A LOW ALONG THE NORTHEAST COAST OF
FLORIDA WHILE FRONT FROMT LOOSES ORGANIZATION IN THE NORTHEASTERN
GULF. SIMULTANEOUSLY...ANOTHER FRONT EXTENDS FROM THE NORTH
ATLANTIC INTO THE CENTRAL BAHAMAS ON MONDAY...JUST TO THE NORTH OF
WESTERN CUBA AND INTO THE CENTRAL GULF OF MEXICO. ON TUESDAY THIS
BOUNDARY IS FORECAST TO RETREAT NORTHWARD INTO THE NORTHWEST
BAHAMAS. ON WEDNESDAY...THIS FRONT IS FORECAST ACROSS THE
NORTH-CENTRAL BAHAMAS...FLORIDA STRAIT INTO THE CENTRAL GULF.
INITIALLY/ON MONDAY...THE ONLY REGION WITH SIGNIFICANT
PRECIPITATION IS EXPECTED IN THE NORTH-CENTRAL BAHAMAS WHERE
AMOUNTS ARE FORECAST TO REACH 05-10MM/DAY AND MAXIMA OF 15MM. ON
TUESDAY...THE FRONT TI THE WEST WILL DEVELOP A NORTES EVENT ALONG
THE SOUTHWEST GULF...TO FAVOR 10-15MM/DAY AND MAXIMA OF 20-40MM IN
CENTRAL VERACRUZ...WHILE THE NORTES WILL ALSO FAVOR 05-10MM/DAY
AND MAXIMA OF 15MM IN CHIAPAS/TABASCO/NORTHERN GUATEMALA. IN THE
BAHAMAS...EXPECT MUCH HEAVIER PRECIPITATION AS THE UPPER SHORT
WAVE TROUGH CROSSES THE REGION FROM WEST TO EAST ACCOMPANIED BY
STRONG UPPER JET DYNAMICS. AS THE DIVERGENT ENTRANCE OF AN UPPER
JET INTERACTS WITH SURFACE FRONT AND ENHANCED ASCENT AHEAD OF THE
UPPER TROUGH...EXPECT STRONG THUNDERSTORMS INCLUDING A RISK FOR
SEVERE WEATHER AND AMOUNTS 15-20MM/DAY AND MAXIMA OF 35-70MM IN
GRAND BAHAMAS AND GRAND ABACO. ON WEDNESDAY...THIS DECREASES TO
05-10MM/DAY AND MAXIMA OF 15MM IN BOTH THE EASTERN PORTION OF THE
NORTHWEST BAHAMAS...AND ION SOUTHERN MEXICO/GUATEMALA.
OVER THE CARIBBEAN...A MID-LEVEL RIDGE CENTERS OVER THE YUCATAN
CHANNEL ON MONDAY MORNING BUT EXTENDS FROM THE SOUTHERN GULF OF
MEXICO/NORTHERN CENTRAL AMERICA ZONALLY INTO THE LEEWARD
ISLANDS...COVERING THE ENTIRETY OF THE GREATER ANTILLES. THIS
RIDGE IS EXPECTED TO BE THE DOMINANT FEATURE THROUGH THE FORECAST
CYCLE...TO FAVOR GRADUAL ENHANCEMENT OF THE TRADE WIND CAP AND
LIMITING RAINFALL AMOUNTS. THE REMNANTS OF A SHEAR LINE WILL
MEANDER NORTHWARD FROM THE LEEWARD ISLANDS ON MONDAY ACROSS PUERTO
RICO ON TUESDAY WHILE WEAKENING. THIS WILL FAVOR 00-05MM/DAY AND
MAXIMA OF 10MM IN THE LEEWARD ISLANDS AND ST. CROIX ON
MONDAY...AND 05-10MM/DAY AND VERY ISOLATED MAXIMA OF 15MM IN
EASTERN PUERTO RICO ON TUESDAY. ALSO IN THE CARIBBEAN...ISOLATED
CONVECTION IS EXPECTED IN SOUTHEAST NICARAGUA AND BOCAS DEL TORO
ON A DAILY BASIS DUE TO TRADE WIND CONVERGENCE. HOWEVER...EXPECT
CONSERVATIVE RAINFALL AMOUNTS.
AN UPPER TROUGH EXTENDS FROM THE NORTH ATLANTIC ACROSS THE ARC OF
THE LESSER ANTILLES INTO NORTH-CENTRAL VENEZUELA ON MONDAY.
ALTHOUGH THIS IS PRODUCING SOME VENTILATION IN NORTHEAST SOUTH
AMERICA...SHEAR IS ENHANCED IN RESPONSE TO FAST TRADES
NORTHEASTERLY TRADES IN THE GUIANAS...WHICH IS LIMITING THE
DEVELOPMENT OF CONVECTION. THE UPPER TROUGH IS FORECAST TO
GRADUALLY MEANDER WESTWARD WHILE FLATTENING AS THE FORECAST CYCLE
PROGRESSES...WHICH WILL LIMITS ITS INFLUENCE IN NORTHERN SOUTH
AMERICA. THIS...AND AN INCREASE IN THE SURFACE PRESSURES OVER THE
ATLANTIC AND CONSEQUENT INCREASE OF THE NORTHEASTERLY TRADES WILL
PUSH THE ITCZ SOUTHWARD INTO AMAPA/NORTHERN PARA...WHICH WILL
FAVOR A DRYING TREND IN THE GUIANAS. YET...ATLANTIC ITCZ
CONVERGENCE WILL STILL FAVOR MODERATE TO LOCALLY HEAVY
ACCUMULATIONS IN AMAPA AND EASTERN FRENCH GUIANA. ON MONDAY EXPECT
10-15MM/DAY AND MAXIMA OF 20-35MM IN FRENCH GUIANA AND SURINAME.
ON TUESDAY AND WEDNESDAY EXPECT 15-20MM/DAY AND ISOLATED OF
25-50MM IN COASTAL AMAPA AND EASTERN FRENCH GUIANA...WHILE WEST
ACROSS THE REST OF FRENCH GUIANA EXPECT MAXIMA OF 20-35MM. NOTE
THAT ON WEDNESDAY...LITTLE PRECIPITATION IS EXPECTED ON SURINAME.
ALSO IN NORTHERN SOUTH AMERICA...THE DESORGANIZATION OF THE
PACIFIC ITCZ WILL LIMIT MAXIMA IN SOUTHWEST/WESTERN COLOMBIA AND
NORTHWEST ECUADOR TO ISOLATED AMOUNTS UNDER 15MM/DAY ON A DAILY
BASIS.
TROPICAL WAVES/TUTT INDUCED PERTURBATIONS/TRADE WIND SURGES
INITIALIZED AT 12 UTC:
NONE
GALVEZ/CHINCHILLA...WPC (USA)
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