225
FXCA20 KWBC 271707
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
106 PM EDT THU APR 27 2023
FORECAST BULLETIN FROM 27 APR 2023 AT 1700 UTC: A SURFACE FRONT IS
MOVING ACROSS SOUTH TEXAS INTO THE NORTHERN GULF OF MEXICO. BY
THURSDAY EVENING THE FRONT IS EXPECTED TO EXTEND INTO CENTRAL
TAMAULIPAS/CENTRAL NUEVO LEON...TO RAPIDLY DISSIPATE AFTERWARDS.
THIS WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15MM IN NORTHEAST MEXICO
ON THURSDAY...WHILE MUCH HIGHER AMOUNTS ORGANIZE OVER THE NORTHERN
GULF AND SOUTHERN USA. ON FRIDAY...A NEW CYCLOGENESIS EVENT IS
EXPECTED IN THE SOUTHERN PLAINS OF THE USA. THIS WILL ORGANIZE A
NEW SURFACE COLD FRONT...FORECAST TO EXTEND ACROSS CENTRAL TEXAS
INTO NORTHERN COAHUILA/NORTHERN CHIHUAHUA BY SATURDAY EVENING. BY
SUNDAY EVENING...THE FRONT IS EXPECTED ACROSS EASTERN
MISSISSIPPI...JUST NORTHWEST OF THE YUCATAN PENINSULA...INTO
CENTRAL VERACRUZ. NOTE THAT THIS FRONT WILL ARRIVE WITH A POTENT
LATE-SEASON NORTES EVENT...THAT WILL DEVELOP A TEHUANTEPECER
LOW-LEVEL JET DURING SUNDAY MORNING...FORECAST TO PEAK AT 40-45KT
DURING SUNDAY AFTERNOON. ON FRIDAY...LATE EVENING FRONTAL
CONVECTION WILL FAVOR 05-10MM/DAY AND ISOLATED MAXIMA OF 15MM
ALONG THE RIO BRAVO. ON SATURDAY...EXPECT OROGRAPHIC ENHANCEMENT
TO FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM IN NORTHERN CHIAPAS AND
SOUTHEAST VERACRUZ. IN TABASCO/CENTRAL AND NORTHERN GUATEMALA AND
OUTHERN BELIZE EXPECT 15-20MM/DAY AND MAXIMA OF 40-80MM WITH A
RISK FOR MCS FORMATION. EVENING THUNDERSTORMS IN THE YUCATAN
PENINSULA WILL FAVOR 05-10MM/DAY AND MAXIMA OF 15-25MM.
IN CENTRAL AMERICA...DIURNAL CONVECTION IS EXPECTED ON A DAILY
BASIS FROM CENTRAL GUATEMALA INTO SOUTHERN HONDURAS/EL SALVADOR
ALONG THE CONTINENTAL DIVIDE...AND TO A LESSER EXTENT IN THE
PACIFIC BASIN OF COSTA RICA. EXPECT ISOLATED DEVELOPMENT WHILE THE
REGION LIES UNDER THE INFLUENCE OF A MID-LEVEL RIDGE ON THURSDAY
AND FRIDAY. HOWEVER...PREFRONTAL CONVECTION ON SATURDAY WILL FAVOR
AN INCREASE IN HONDURAS...EL SALVADOR AND SOUTHERN GUATEMALA TO
05-10MM/DAY AND MAXIMA OF 15-35MM. IN SOUTHERN CENTRAL AMERICA...A
GRADUAL INCREASE IN AVAILABLE MOISTURE AFTER FRIDAY WILL SUSTAIN A
GRADUAL INCREASE IN ACCUMULATIONS IN DIURNAL CONVECTION. BY
SATURDAY EXPECT 05-10MM/DAY AND ISOLATED MAXIMA OF 15-25MM IN THE
PACIFIC BASIN OF COSTA RICA BUT ALSO IN THE AZUERO PENINSULA
REGION AND MOST OF EASTERN PANAMA.
IN THE CARIBBEAN...MODELS CONTINUE TO SHOW THE STRENGTHENING OF A
MID-LEVEL RIDGE...FORECAST TO ESTABLISH OVER THE CENTRAL
CARIBBEAN/NORTH OF THE GUAJIRA PENINSULA BY FRIDAY MORNING...AND
PERSIST THROUGH THE CYCLE WHILE MEANDERING NORTHEASTWARD INTO
PUERTO RICO AND HISPANIOLA BY SUNDAY/MONDAY. THIS WILL GENERALLY
FAVOR FAIR WEATHER CONDITIONS...ESPECIALLY IN COMBINATION WITH AN
UPPER CONVERGENT SIGNATURE OF THE MJO...LEADING TO WIDELY ISOLATED
COVERAGE OF PRECIPITATING CONVECTION. WETTER CONDITIONS WILL
CONTINUE TO CLUSTER IN PORTIONS OF THE LESSER ANTILLES IN
ASSOCIATION WITH AN ILL-DEFINED SHEAR LINE STRUCTURE. THIS WILL
FAVOR 05-10MM/DAY AND MAXIMA OF 15-20MM INITIALLY...GRADUALLY
DECREASING TO 00-05MM/DAY AND MAXIMA OF 10MM BY SATURDAY.
IN SOUTH AMERICA...VENTILATION WILL BE PRIMARILY ENHANCED IN AREAS
TO THE WEST...ALONG THE SOUTHERN FRINGES OF THE SUBEQUATORIAL
RIDGE. THE LATTER IS FORECAST TO GENERALLY EXTEND ITS AXIS ACROSS
TRINIDAD AND TOBAGO...THE ABC ISLANDS...INTO SAN
ANDRES/PROVIDENCIA/NICARAGUA INTIALLY...TO FORM A CLOSED HIGH OVER
WESTERN VENEZUELA BY SATURDAY EVENING. IN THE LOWER
LEVELS...AVAILABLE MOISTURE WILL PEAK IN THE NORTHWEST
AMAZON/ORINOQUIA...AND WILL BE ADVECTED WESTWARD INTO THE ANDEAN
REGION. THIS WILL FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM IN
EASTERN ECUADOR/NORTHERN PERU ON THURSDAY AND 10-15MM/DAY AND
MAXIMA OF 20-40MM ELSEWHERE IN EASTERN AND CENTRAL
COLOMBIA/WESTERN VENEZUELA. IN THE PACIFIC BASIN OF WESTERN
COLOMBIA AND ECUADOR EXPECT 15-20MM/DAY AND MAXIMA OF 40-80MM
AIDED BY ENHANCED ONSHORE FLOW IN THE LOWER TROPOSPHERE. ON
FRIDAY...EXPECT A PEAK IN CONVECTION IN ECUADOR AND SOUTHWEST
COLOMBIA WHERE ENHANCED ONSHORE FLOW WILL FAVOR 15-30MM/DAY AND
MAXIMA OF 50-100MM. IN THE EJE CAFETERO EXPECT 15-20MM/DAY AND
MAXIMA OF 30-60MM. ALONG THE NET IN SOUTHERN VENEZUELA INTO
EASTERN COLOMBIA/SOUTHWEST VENEZUELA EXPECT 10-15MM/DAY AND MAXIMA
OF 20-40MM. ON SATURDAY...INCREASING VENTILATION AND AVAILABLE
MOISTURE...AS WELL AS WAVE IN THE TRADES APPROACHING FROM THE EAST
WILL FAVOR SCATTERED MODERATE PRECIPITATION IN CENTRAL/WESTERN
COLOMBIA AND IN THE WESTERN ORINOQUIA WHERE AMOUNTS ARE FORECAST
TO REACH 15-20MM/DAY AND MAXIMA OF 30-60MM. IN NORTHWEST
VENEZUELA/NORTHERN COLOMBIA EXPECT 10-15MM/DAY AND MAXIMA OF
20-35MM WHILE IN SOUTHERN COLOMBIA...MOST OF ECUADOR AND NORTHWEST
BRAZIL EXPECT 10-15MM/DAY AND MAXIMA OF 20-45MM.
GALVEZ/ACOSTA...WPC (USA)
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