557
FXCA20 KWBC 151902
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 PM EDT WED MAR 15 2023
FORECAST BULLETIN FROM 15 MAR 2023 AT 19 UTC: A SURFACE FRONT IS
MOVING INTO NORTHWEST MEXICO ON WEDNESDAY...TO FAVOR 10-15MM/DAY
AND MAXIMA OF 20-35MM AS IT INTERACTS WITH THE SIERRA SAN PEDRO
MARTIR. THE FRONT THEN MOVES SOUTHWARD...AND BY THURSDAY EVENING
IT WILL FORM A DISSIPATING BOUNDARY ACROSS CENTRAL SONORA INTO
CENTRAL BAJA CALIFORNIA. THE ASSOCIATED UPPER TROUGH WILL ENTER IN
PHASE WITH A POLAR TROUGH ACROSS THE NORTHERN PLAINS OF THE USA TO
SUSTAIN CYCLOGENESIS ON THURSDAY. THIS WILL DEVELOP A SURFACE
FRONT THAT IS FORECAST TO REACH THE GULF OF MEXICO COAST BY FRIDAY
MORNING. BY FRIDAY EVENING EXPECT THIS FRONT TO EXTEND ACROSS THE
FLORIDA PANHANDLE INTO A LOW NEAR 23N 95W IN THE WESTERN GULF OF
MEXICO...INTO CENTRAL VERACRUZ. A SHORT-LIVED NORTES EVENT IS
EXPECTED WITH THIS SYSTEM...WHICH WILL TRIGGER AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM IN PORTIONS OF NORTHERN
VERACRUZ/HIDALGO IN THE SIERRA MADRE ORIENTAL ON FRIDAY.
IN THE MEAN TIME...TWO SURFACE FRONTS ARE PROPAGATING ACROSS
NORTHERN PORTIONS OF THE BASIN ON WEDNESDAY. NOTE THAT THE CURRENT
UPPER DIVERGENT PULSE OF THE MJO HAS RESULTED IN THE WEAKENING OF
THE TRADE WIND CAP ACROSS MOST OF CENTRAL AMERICA...THE WESTERN
AND NORTHERN CARIBBEAN. NOTE THAT SHORT WAVE PERTURBATIONS
PROPAGATING IN THE MID-LEVEL WESTERLIES ARE PLAYING A ROLE IN
ENHANCING DEEP-LAYER ASCENT...AND FAVOR THE DEVELOPMENT OF A FEW
THUNDERSTORMS IN THE NORTHERN CARIBBEAN. THIS PROCESS WILL PRODUCE
ADDITIONAL ENHANCEMENT TO CONVECTION DEVELOPMENT IN ASSOCIATION
WITH THE FRONT ESPECIALLY ACROSS NORTHERN CENTRAL AMERICA AND
CUBA/THE BAHAMAS ON WEDNESDAY. IN TERMS OF THE POSITION OF THE
SOUTHERN FRONT...ON WEDNESDAY EXPECT THE BOUNDARY ACROSS THE
CENTRAL BAHAMAS...CENTRAL CUBA...NORTHEAST YUCATAN PENINSULA. BY
THURSDAY EVENING EXPECT IT ACROSS PUERTO RICO/VI...SOUTH OF
HISPANIOLA AND JAMAICA NEAR 18N...INTO THE COZUMEL REGION IN
MEXICO. BY FRIDAY EVENING EXPECT THE BOUNDARY ACROSS THE SOUTHERN
LEEWARD ISLANDS...INTO A WEAKENING BOUNDARY ACROSS THE CENTRAL
CARIBBEAN AND INTO JAMAICA/CAYMAN ISLANDS. A SHORT-LIVED SHEAR
LINE IS ALSO EXPECTED ON WEDNESDAY...TO EXTEND ACROSS THE CAYMAN
ISLANDS INTO NORTHEAST HONDURAS. THIS WILL INTERACT WITH CURRENT
MOIST POOL AND INSTABILITY IN HONDURAS/NICARAGUA TO FAVOR STRONG
CONVECTION ON WEDNESDAY. THE NORTHERN FRONT WILL ENTER THE
NORTHWEST BAHAMAS ON WEDNESDAY...AND BY THURSDAY EVENING IT WILL
EXTEND AS A WEAKENING BOUNDARY ACROSS THE TURKS AND CAICOS AND
EASTERN CUBA. NOTE LOWER RAINFALL TOTALS WITH THIS SYSTEM GIVEN
THAT THE SOUTHERN FRONT IS EXPECTED TO SWEEP THE DEEP-LAYER
MOISTURE SOUTHWARD...LEAVING A MUCH DRIER AIR MASS AVAILABLE WHEN
THE NORTHERN FRONT ARRIVES. IN TERMS OF ACCUMULATIONS...ON
WEDNESDAY EXPECT THE STRONGEST CONVECTION IN SOUTHERN AND EASTERN
HONDURAS AND MOST OF NORTHERN NICARAGUA...WHERE AMOUNTS WILL
LIKELY REACH 15-20MM/DAY AND MAXIMA OF 25-50MM...WITH THE SLIGHT
RISK FOR ISOLATED SEVERE CONVECTION. IN EASTERN CUBA AND INAGUA
EXPECT SIMILAR AMOUNTS...WHILE IN THE REST OF THE BAHAMAS...SOUTH
OF NEW PROVIDENCE...EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM WITH
AN ENHANCED RISK FOR SQUALLY WEATHER. IN WESTERN CUBA AND THE
CAYMAN ISLANDS EXPECT 05-10MM/DAY AND MAXIMA OF 15MM. ON
THURSDAY...EXPECT THE HEAVIEST PRECIPITATION DEVELOPING IN
ELEVATED TERRAIN IN HISPANIOLA...WHERE EXPECT 15-20MM/DAY AND
MAXIMA OF 25-50MM. ELSEWHERE IN THE ISLAND EXPECT 10-15MM/DAY AND
MAXIMA OF 20-35MM. SIMILAR AMOUNTS ARE EXPECTED IN JAMAICA AND IN
EASTERN PUERTO RICO/WESTERN VI. IN THE TURKS AND CAICOS/SOUTHEAST
BAHAMAS AND EASTERN CUBA EXPECT 05-10MM/DAY AND MAXIMA OF 15MM. ON
FRIDAY...EXPECT THE MOIST PLUME TO CONTINUE INTERACTING WITH
TERRAN IN JAMAICA...WHERE EXPECT 10-15MM/DAY AND MAXIMA OF
20-35MM. IN WESTERN CUBA EXPECT 05-10MM/DAY AND ISOLATED MAXIMA OF
15MM WITH THE MOIST PLUME. IN THE SOUTHERN LEEWARD ISLANDS EXPECT
00-05MM/DAY AND MAXIMA OF 10MM.
ACTIVE CONVECTION IS TO CONTINUE IN PORTIONS OF CENTRAL AMERICA
DUE TO UNSEASONABLY HIGH VALUES OF PRECIPITABLE WATER
AVAILABLE...WEAK TRADES AND WESTERLIES IN PORTIONS OF THE PACIFIC
BASIN...AND A FEW SHORT WAVE TROUGHS PROPAGATING ACROSS SOUTHERN
MEXICO AND NORTHERN CENTRAL AMERICA IN THE MID-LEVELS. VENTILATION
REMAINS ALSO FAVORABLE UNDER THE INFLUENCE OF THE SUBEQUATORIAL
RIDGE. AS THE MJO WET PULSE AND GENERAL DYNAMICS DECREASE IN
STRENGTH IN THE NEXT FEW DAYS...EXPECT A GENERAL DECREASING TREND
IN RAINFALL ACCUMULATIONS. ON WEDNESDAY...EXPECT THE HEAVIEST IN
NICARAGUA AND HONDURAS WHERE AMOUNTS WILL REACH 15-20MM/DAY AND
MAXIMA OF 25-50MM WITH AN ISOLATED RISK FOR SEVERE CONVECTION. IN
THE PACIFIC BASIN OF COSTA RICA AND IN NORTHWEST HONDURAS/CENTRAL
GUATEMALA EXPECT 05-10MM/DAY AND MAXIMA OF 15-30MM. SIMILAR
AMOUNTS ARE EXPECTED IN THE EJE VOLCANICO AND SIERRA MADRE
ORIENTAL/COASTAL PLAIN IN CENTRAL MEXICO...WHERE THE RISK FOR
SQUALLY CONVECTION AND ISOLATED HAIL IS STILL POSSIBLE ON
WEDNESDAY. ON THURSDAY...THE CORE AREAS THAT SHOULD EXPECT
PRECIPITATION ARE THE PACIFIC BASIN OF COSTA RICA AND MOST OF
SOUTHERN HONDURAS/EL SALVADOR/GUATEMALA...WHERE EXPECT 05-10MM/DAY
AND MAXIMA OF 15-25MM. IN CENTRAL HONDURAS AND EASTERN NICARAGUA
EXPECT 05-10MM/DAY AND MAXIMA OF 10MM. IN CENTRAL MEXICO EXPECT A
DECREASE TO MAXIMA OF 10MM. ON FRIDAY EXPECT 05-10MM/DAY AND
MAXIMA OF 15-25MM IN WESTERN COSTA RICA AND IN NORTHWEST
NICARAGUA/CENTRAL HONDURAS.
IN NORTHERN SOUTH AMERICA...THE MOST ACTIVE CONVECTION IS EXPECTED
PRIMARILY IN COLOMBIA AND PORTIONS OF ECUADOR...AS THE REGION
REMAINS UNDER THE ENHANCED VENTILATION AREA OF THE SUBEQUATORIAL
RIDGE. EXPECT A GENERAL DECREASING TREND AS VENTILATION DECREASES
AND THE PACIFIC NORTHERN ITCZ MEANDERS NORTHWARD AND REORGANIZES.
ON WEDNESDAY EXPECT THE LARGEST AMOUNTS IN CENTRAL AND NORTHERN
COLOMBIA WHERE TOTALS ARE FORECAST TO REACH 15-20MM/DAY AND MAXIMA
OF 25-50MM. SIMILAR AMOUNTS ARE EXPECTED IN THE CENTRAL COAST OF
ECUADOR. ON THURSDAY...EXPECT SIMILAR AMOUNTS IN COASTAL
ECUADOR...WHILE IN MOST OF ANDEAN AND NORTHERN COLOMBIA EXPECT
10-15MM/DAY AND MAXIMA OF 20-40MM. ON FRIDAY...EXPECT 10-15MM/DAY
AND SCATTERED MAXIMA OF 20-35MM IN MOST OF NORTHERN ECUADOR AND
COLOMBIA.
GALVEZ/ACOSTA/ALAMO...WPC (USA)
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