267
FXCA20 KWBC 261659
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1259 PM EDT WED APR 26 2023
FORECAST BULLETIN FROM 26 APR 2023 AT 1830 UTC: AN UPPER TROUGH IS
MOVING ACROSS NORTHERN MEXICO AND IS FORECAST TO INTERACT WITH THE
SOUTHERN END OF A DRY LINE EXTENDING INTO NORTHERN COAHUILA ON
WEDNESDAY EVENING. THIS WILL SUSTAIN A RISK FOR SEVERE WEATHER AND
ACCUMULATION OF 05-10MM/DAY AND VERY ISOLATED MAXIMA OF 15-20MM
THROUGH EARLY THURSDAY. A SURFACE FRONT THEN MOVES IN FROM THE
SOUTHERN PLAINS OF THE USA. BY THURSDAY EVENING THE FRONT IS
EXPECTED TO EXTEND INTO CENTRAL TAMAULIPAS/CENTRAL NUEVO LEON...TO
RAPIDLY DISSIPATE OVER MEXICO AFTERWARDS. THIS WILL FAVOR
05-10MM/DAY AND MAXIMA OF 15MM IN NORTHEAST MEXICO...ALTHOUGH MUCH
HIGHER AMOUNTS ARE EXPECTED OVER THE NORTHERN GULF AND SOUTHERN
USA. ON FRIDAY...A NEW CYCLOGENESIS EVENTS 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
CHIHUAHUA BY FRIDAY EVENING. INTERACTION WITH THE UPPER TROUGH
WILL FAVOR ANOTHER ROUND OF SEVERE CONVECTION FOR NORTHEAST
COAHUILA WHERE EXPECT 05-10MM/DAY AND MAXIMA OF 15MM.
ELSEWHERE...EXPECT ISOLATED CONVECTION ALONG THE EASTERN SIERRA
MADRE ORIENTAL ON A DAILY BASIS.
A MID-LEVEL RIDGE EXTENDS OVER SOUTHERN MEXICO ON WEDNESDAY...AND
IS FORECAST TO MEANDER EASTWARD THROUGH THE CYCLE...TO CENTER OVER
THE CENTRAL CARIBBEAN BY FRIDAY EVENING. THE RIDGE ENHANCING THE
TRADE WIND CAP OVER NORTHERN CENTRAL AMERICA...WHICH WILL FAVOR TO
A DECREASE IN THE COVERAGE OF AFTERNOON/EVENING CONVECTION AND
ASSOCIATED AMOUNTS WITH RESPECT TO PREVIOUS DAYS. STILL...DIURNAL
INSTABILITY AND AVAILABLE MOISTURE WILL BE SUFFICIENT FROM
SOUTHERN HONDURAS/EL SALVADOR INTO WESTERN GUATEMALA/CHIAPAS...TO
SUSTAIN AFTERNOON/EVENING THUNDERSTORMS ON A DAILY BASIS. ON
WEDNESDAY EXPECT 10-15MM/DAY AND ISOLATED MAXIMA OF
20-35MM...DECREASING TO 05-10MM/DAY AND MAXIMA OF 15-25MM
THEREAFTER. DRIER CONDITIONS CONTINUE IN SOUTHERN CENTRAL
AMERICA...WHERE DIURNAL CONVECTION WILL LIMIT GENERALLY TO THE
PACIFIC BASIN OF COSTA RICA AND PRODUCE LIGHT RAINFALL
ACCUMULATIONS.
TO THE EAST...AS THE MID-LEVEL RIDGE PATTERN STRENGTHENS OVER THE
CENTRAL/NORTHERN CARIBBEAN AND BAHAMAS...EXPECT GENERALLY A
DECREASING TREND IN ACCUMULATIONS. YET...A MOIST PLUME MOVING FROM
SOUTH TO NORTH INTO HISPANIOLA WILL FAVOR LOCALLY HIGHER AMOUNTS
ON WEDNESDAY...WHEN EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM. THIS
DECREASES TO 05-10MNM/DAY AND MAXIMA OF 15-25MM. ISOLATED
CONVECTION IS ALSO EXPECTED IN PUERTO RICO IN A DAILY
BASIS...FAVORING HIGHER AMOUNTS IN THE CORDILLERA. IN THE LESSER
ANTILLES...HOWEVER...VENTILATION FROM AN UPPER TROUGH AND A SHEAR
LINE ENTERING FROM THE ATLANTIC WILL CONTINUE TO FAVOR WET
CONDITIONS. ON WEDNESDAY EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM
FROM GUADELOUPE INTO TRINIDAD AND TOBAGO. THIS GRADUALLY DECREASES
TO 05-10MM/DAY AND MAXIMA OF 15MM BY FRIDAY.
A KELVIN WAVE IS EXITING THE BASIN AS IT PROPAGATES INTO AFRICA.
THIS IS LEADING TO A GRADUAL DECREASE IN VENTILATION IN THE
GUIANAS. HOWEVER...ITCZ CONVERGENCE AND REMAINING ENHANCED
VENTILATION OVER SURINAME AND FRENCH GUIANA WILL FAVOR ANOTHER
ROUND OF HEAVY RAINS ON WEDNESDAY...WHERE AMOUNTS ARE FORECAST TO
REACH 15-30MM/DAY AND MAXIMA OF 40-80MM. YET...AS THE REGION
STABILIZES AND AN ENHANCED UPPER CONVERGENT PATTERN
ESTABLISHES...EXPECT A RAPID DECREASE IN AMOUNTS AFTER
THURSDAY...TO MAXIMA OF 15-25MM BY THURSDAY-FRIDAY. TO THE
WEST...ENHANCED MOISTURE CONVERGENCE IN THE LOWER LEVELS WILL
FAVOR MODERATE AFTERNOON/EVENING CONVECTION IN CENTRAL COLOMBIA ON
WEDNESDAY...AIDED BY ENHANCED VENTILATION TO THE SOUTH OF THE
SUBEQUATORIAL RIDGE. EXPECT 15-20MM/DAY AND MAXIMA OF 25-50MM.
ITCZ CONVERGENCE WILL ALSO FAVOR MODERATE AMOUNTS IN THE PACIFIC
BASIN OF ECUADOR AND NORTHERN PERU ON WEDNESDAY...WHERE EXPECT
10-15MM/DAY AND MAXIMA OF 20-45MM. ON THURSDAY...AN INCREASE IN
THE ONSHORE FLOW COMPONENT IN THE LOW-LEVELS WILL STIMULATE
MOISTURE CONVERGENCE ALONG THE PACIFIC BASINS OF COLOMBIA AND
ECUADOR. THIS WILL FAVOR 15-20MM/DAY AND MAXIMA OF 40-80MM ON
THURSDAY. ACTIVE CONVECTION IS ALSO EXPECTED EAST OF THE ANDES IN
RESPONSE TO INCREASING VENTILATION BETWEEN THE SUBEQUATORIAL RIDGE
AND THE BOLIVIAN HIGH...AND INCREASED MOISTURE CONVERGENCE AS
EASTERLY TRADES INCREASE ACROSS THE CENTRAL AMAZON BASIN. THIS
WILL FAVOR 15-20MM/DAY AND MAXIMA OF 30-60MM IN NORTHERN
PERU/EASTERN ECUADOR...AND 10-15MM/DAY AND MAXIMA OF 20-40MM FROM
SOUTHERN/WESTERN VENEZUELA INTO MOST OF EASTERN COLOMBIA BY
THURSDAY. ON FRIDAY...A PEAK IN ONSHORE FLOW WILL TRIGGER
15-30MM/DAY AND MAXIMA OF 50-100MM IN COASTAL ECUADOR/SOUTHWEST
COLOMBIA...WITH A RISK FOR MCS FORMATION. IN THE EJE CAFETERO
EXPECT 15-20MM/DAY AND MAXIMA OF 30-60MM...WHILE ACTIVITY IN
NORTHEAST COLOMBIA/WESTERN AND CENTRAL VENEZUELA FAVORS
10-15MM/DAY AND MAXIMA OF 20-45MM.
GALVEZ/ACOSTA...WPC (USA)
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