949
FXCA20 KWBC 031422
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1021 AM EDT WED MAY 03 2023
FORECAST BULLETIN FROM 03 MAY 2023 AT 1500 UTC: EMBEDDED IN
WEST-SOUTHWESTERLY FLOW IN THE UPPER TROPOSPHERE...SHORT WAVE
TROUGHS ARE PROPAGATING EASTWARD ACROSS MEXICO. AVAILABLE MOISTURE
CONTINUES LIMITED AND CORNERED ALONG THE SIERRA MADRE
ORIENTAL...WHERE MOIST CONVECTION AND ISOLATED PRECIPITATION IS
EXPECTED ON A DAILY BASIS. ON WEDNESDAY...A SHORT WAVE TROUGH WILL
PRODUCE SUFFICIENT LIFT TO TRIGGER LIGHT PRECIPITATION IN PORTIONS
OF THE SIERRA MADRE OCCIDENTAL WHERE EXPECT MAXIMA UNDER 10MM/DAY.
THE UPPER TROUGH WILL ALSO VENTILATE AFTERNOON CONVECTION IN
COAHUILA WHERE EXPECT 05-10MM/DAY AND ISOLATED MAXIMA OF 15MM WITH
A SLIGHT RISK FOR SEVERITY. ALSO ON WEDNESDAY...AFTERNOON
CONVECTION IS EXPECTED IN OAXACA/PUEBLA WHERE AMOUNTS ARE FORECAST
IN THE 05-10MM/DAY AND MAXIMA OF 15MM RANGE. ON THURSDAY...EXPECT
HIGHER ACCUMULATIONS IN COAHUILA AS MOIST INFLOW FROM THE NORTHERN
GULF OF MEXICO INCREASES. THIS WILL FAVOR 05-10MM/DAY AND MAXIMA
OF 15-25MM WITH A RISK FOR SEVERITY. THE APPROACHING UPPER TROUGH
WILL ALSO FAVOR AN INCREASE IN EASTERN PORTIONS OF THE EJE
VOLCANICO TO TRIGGER 05-10MM/DAY AND MAXIMA OF 15-25MM FROM
HIDALGO/QUERETARO INTO PUEBLA/TLAXCALA. ON FRIDAY...A SHORT WAVE
TROUGH APPROACHING INTO SOUTHERN MEXICO WILL FAVOR AN INCREASE IN
THE COVERAGE OF DIURNAL CONVECTION...FAVORING AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM ALONG THE SIERRA MADRE ORIENTAL
INTO PORTIONS OF CENTRAL MEXICO.
A MID-LEVEL RIDGE CONTINUES EXTENDING OVER THE ENTIRE CARIBBEAN
WHILE CENTERING OVER THE GREATER ANTILLES ON WEDNESDAY.
THIS...TOGETHER WITH AN ENHANCED UPPER CONVERGENT PATTERN FAVORED
BY PHASES 4 AND 5 OF THE MJO...WILL CONTINUE TO LIMIT VERTICAL
DEVELOPMENT ACROSS THE CARIBBEAN RESULTING IN LOW RAINFALL
ACCUMULATIONS. THIS IS CONSISTENT AS WELL WITH A GRADUAL
ACCELERATION OF THE EASTERLY TRADES ACROSS THE ENTIRE
BASIN...WHICH WILL ADD LOW-LEVEL SHEAR TO REINFORCE THE CURRENT
DRY PATTERN ACROSS THE REGION. MODELS SHOW THE MID-LEVEL RIDGE
SPLITTING IN TWO BY THURSDAY AND ON...AS A BROAD MID/UPPER TROUGH
DEEPENS OVER THE BAHAMAS/NORTH OF HISPANIOLA. THIS TROUGH WILL
EVENTUALLY LEAD TO A DECREASE IN THE SURFACE PRESSURES IN NORTHERN
COLOMBIA...FAVORING A TRANSITION TOWARDS WETTER CONDITIONS DURING
THE WEEKEND. BUT IN THE MEAN TIME...EXPECT VERY LITTLE
PRECIPITATION IN THE ENTIRE CARIBBEAN AND NORTHERN
COLOMBIA/NORTHERN VENEZUELA. ISOLATED MODERATE AMOUNTS ARE STILL
POSSIBLE IN PORTIONS OF HISPANIOLA...SOUTHEAST CUBA AND PUERTO
RICO IN AFTERNOON CONVECTION...HIGHLIGHTED BY OROGRAPHY. BUT ANY
SIGNIFICANT AMOUNTS WILL BE ISOLATED.
IN THE LOW-LEVELS...A STATIONARY FRONT IS WEAKENING ACROSS THE
CENTRAL BAHAMAS ON WEDNESDAY. THIS IS STILL A FOCUS FOR MOISTURE
CONVERGENCE AND WILL FAVOR MAXIMA UNDER 10MM/DAY. ANOTHER FRONT IS
ORGANIZING AND MOVING SOUTHWARD ACROSS THE EXTREME NORTHWEST
BAHAMAS...AND BY WEDNESDAY EVENING IS FORECAST JUST TO THE NORTH
OF ELEUTHERA. BY THURSDAY EVENING EXPECT A STATIONARY BOUNDARY
ACROSS THE CENTRAL BAHAMAS INTO BIMINI. BY FRIDAY EVENING...EXPECT
THE BOUNDARY TO EXTEND ACROSS THE CENTRAL BAHAMAS INTO ANDROS
ISLAND. ALSO ON FRIDAY...A PREFRONTAL SHEAR LINE IS EXPECTED TO
DEVELOP ACROSS HISPANIOLA AND JAMAICA. THE FRONT WILL PRODUCE
LITTLE PRECIPITATION IN THE BAHAMAS...WHILE IN HISPANIOLA...EXPECT
DIURNAL CONVECTION ON A DAILY BASIS WITH FORECAST AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. THE SHEAR LINE WILL FAVOR
SIMILAR AMOUNTS ON FRIDAY. WETTER CONDITIONS ARE POSSIBLE IN
HISPANIOLA DURING THE WEEKEND AS THE FRONT MEANDERS SOUTHWARD
AGAIN.
IN CENTRAL AMERICA...AN ILL-DEFINED EASTERLY WAVE IS PROPAGATING
ACROSS SOUTHERN GUATEMALA ON WEDNESDAY...AND IS FORECAST TO
RAPIDLY EXIT INTO OPEN WATERS OF THE EASTERN PACIFIC. IN THE
MID-UPPER LEVELS...A SHORT WAVE TROUGH IS PROPAGATING ACROSS
HONDURAS/EL SALVADOR ON WEDNESDAY. THIS IS INTERACTING WITH A
45-50MM PRECIPITABLE WATER POOL LOCATED IN NORTHERN
HONDURAS/SOUTHERN BELIZE...FAVORING A FEW DEEP CONVECTIVE CELLS ON
WEDNESDAY MORNING. THIS INTERACTION WILL FAVOR ACTIVE AFTERNOON
CONVECTION IN HONDURAS...EL SALVADOR AND CENTRAL GUATEMALA/BELIZE
ON WEDNESDAY...WHERE EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM. IN
SOUTHERN GUATEMALA EXPECT 05-10MM/DAY AND MAXIMA OF 15-25MM.
ACCUMULATIONS ARE BOUND TO DECREASE AFTER AS A CELL OF THE
MID-LEVEL RIDGE STRENGTHENS OVER THE REGION. IN SOUTHERN CENTRAL
AMERICA...EXPECT LIGHT PRECIPITATION PRIMARILY IN COSTA RICA AND
WESTERN PANAMA ASSOCIATED WITH TRADE WIND CONVERGENCE. LIMITED
AVAILABLE MOISTURE WILL FAVOR MAXIMA GENERALLY UNDER 15MM/DAY.
THIS INCREASES ON THURSDAY TO MAXIMA OF 15-25MM DUE TO AN INCREASE
IN MOISTURE CONVERGENCE...DECREASING AGAIN ON FRIDAY.
A DRY SPELL CONTINUES IN NORTHERN SOUTH AMERICA AS A DRY AIR MASS
HAS SET UP IN LATITUDES TO THE NORTH OF 05N...WHICH SHOWS AS A
BROAD REGION OF BELOW AVERAGE PRECIPITABLE WATER. DEEP CONVECTION
IS LIMITED TO THE NET...LOCATED ALONG NORTHERN BRASIL INTO
SOUTHERN COLOMBIA...WHILE AREAS TO THE NORTH ARE PRONE TO
GENERALLY FAIR WEATHER CONDITIONS AND VERY ISOLATED DEVELOPMENT.
HIGHER ACCUMULATIONS ARE EXPECTED IN THE PACIFIC BASINS OF ECUADOR
AND SOUTHWEST COLOMBIA...WHERE ENHANCED ONSHORE FLOW WILL FAVOR
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM ON WEDNESDAY AND
THURSDAY. AS AN UPPER TROUGH DEEPENS ACROSS THE CENTRAL CARIBBEAN
INTO NORTHERN COLOMBIA ON FRIDAY AND SATURDAY...EXPECT A LOWERING
OF THE PRESSURES IN NORTHWEST AND NORTH-CENTRAL COLOMBIA INTO THE
WEEKEND. THIS WILL FAVOR AN INCREASE IN THE ONSHORE COMPONENT OF
THE LOW-LEVEL WINDS IN THE PACIFIC...FAVORING 10-15MM/DAY AND
MAXIMA OF 20-45MM IN WESTERN COLOMBIA BY FRIDAY. AN ADDITIONAL
INCREASE IS EXPECTED BY SATURDAY...WHEN SCATTERED CONVECTION
SHOULD RETURN TO PORTIONS OF NORTHERN AND NORTH-CENTRAL COLOMBIA.
GALVEZ/ACOSTA/ALAMO...WPC (USA)
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