996
FXCA20 KWBC 041814
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
214 PM EDT TUE APR 04 2023
FORECAST BULLETIN FROM 04 APR 2023 AT 1845 UTC: A WET SPELL IS
EXPECTED TO CONTINUE ACROSS THE WESTERN SECTORS OF
ECUADOR...COLOMBIA AND THE NORTHWESTERN SECTIONS OF PERU. THE
3-DAY RAINFALL MAXIMA COULD BE AS MUCH AS 100-200MM...BUT SOME
ISOLATED AREAS OF ECUADOR AND NORTHWESTERN PERU HAS THE POTENTIAL
OF OBSERVING 200-300MM. THE FAVORABLE MJO PHASE IS ASSOCIATED WITH
A LONG FETCH LOW LEVEL WESTERLY WIND FLOW...WHICH IS OVER
ANOMALOUSLY WARM WATERS...COMBINED WITH A LOW SHEAR MID LEVEL
FLOW...AND WILL ENHANCE MOISTURE CONVERGENCE AT THE FOOTHILLS OF
THE CORDILLERA. GIVEN THIS PATTERN...THERE IS A RISK OF MCS ACROSS
THE AREA...AND THEREFORE PERSISTENT MODERATE TO HEAVY RAINFALL
WITH THE THUNDERSTORMS. THE RAINFALL MAXIMA FOR TODAY WILL RANGE
BETWEEN 30-60MM ACROSS NORTHWESTERN ECUADOR AND WESTERN
COLOMBIA...TO 50-100MM ACROSS WEST CENTRAL ECUADOR TO NORTHWESTERN
PERU. FOR WEDNESDAY...NORTHWESTERN PERU...NORTHWESTERN ECUADOR AND
SOUTHWESTERN COLOMBIA WILL HAVE MAXIMA BETWEEN 75-100MM...WHILE
WEST CENTRAL ECUADOR AND WEST CENTRAL COLOMBIA WILL RANGE BETWEEN
30-70MM. ON THURSDAY INTO VERY EARLY FRIDAY...WEST CENTRAL TO
SOUTHWEST COLOMBIA WILL OBSERVE MAXIMA BETWEEN 30-100MM...BUT
WESTERN ECUADOR INTO NORTHWESTERN PERU HAS THE POTENTIAL OF
OBSERVING MAXIMA BETWEEN 100-200MM WITH A RISK OF MCS.
A HIGH PRESSURE LOCATED WEST OF THE AZORES WILL MEANDER OVER THE
AREA TODAY AND WEDNESDAY...BUT WILL MOVE EAST BY
THURSDAY...ALLOWING FOR ANOTHER SURFACE HIGH PRESSURE TO POSITION
ITSELF ACROSS THE CENTRAL ATLANTIC. THIS WILL CAUSE AN EASTERLY
WIND FLOW ACROSS THE CARIBBEAN AND SOUTHEASTERLY TO SOUTHERLY
WINDS ACROSS THE GULF OF MEXICO. THERE IS ALSO A SURFACE LOW
ACROSS THE CENTRAL US THAT IS HELPING WITH THE SOUTHERLY WIND FLOW
ACROSS THE GULF OF MEXICO...AND WILL CONTINUE INTO WEDNESDAY...BUT
A SURFACE HIGH PRESSURE WILL MOVE INTO THE CENTRAL US BY
THURSDAY...CAUSING THE WINDS ACROSS THE GULF OF MEXICO TO BECOME
SOUTHEASTERLY ONCE AGAIN. MID AND UPPER LEVEL TROUGHS WILL AFFECT
PORTIONS OF THE WESTERN ATLANTIC INTO THE CARIBBEAN. THE MID TO
UPPER LEVEL TROUGHS WILL ENHANCE INSTABILITY OVER THE AREA AND
WILL BE REFLECTED AT THE SURFACE AS AN INDUCED TROUGH. AN INCREASE
IN SHOWER AND THUNDERSTORM DEVELOPMENT IS EXPECTED ON WEDNESDAY
AND THURSDAY ACROSS PUERTO RICO AND OTHER ISLANDS OF THE NORTHEAST
CARIBBEAN. THE AVAILABLE MOISTURE WILL REMAIN NEAR NORMAL TODAY
ACROSS THE CARIBBEAN...BUT IT IS INCREASING GRADUALLY...AND BY
WEDNESDAY INTO THURSDAY...THE AVAILABLE MOISTURE WILL BE JUST
ABOVE NORMAL. THE RELATIVE HUMIDITY IN THE MID LEVELS WILL BE WELL
ABOVE NORMAL ON WEDNESDAY AND THURSDAY...SO THE MOISTURE COLUMN IS
FAIRLY DEEP INTO THE ATMOSPHERE...WHICH WILL ENHANCE THE POTENTIAL
FOR SIGNIFICANT RAINFALL. THE DAILY RAINFALL TOTALS TODAY ARE NOT
EXPECTED TO BE SIGNIFICANT...BUT ON WEDNESDAY AND THURSDAY...THE
RAINFALL MAXIMA COULD BE COULD BE IN THE 25-50MM RANGE FOR PUERTO
RICO AND THE USVI...WHILE THE LESSER ANTILLES AND OTHER SECTIONS
OF THE GREATER ANTILLES COULD SEE MAXIMA BETWEEN 15-30MM EACH DAY.
SOUTHERLY WINDS ACROSS THE GULF OF MEXICO TODAY WILL ALLOW FOR
ONLY A FEW SHOWERS ACROSS MEXICO...BUT NOTHING SIGNIFICANT.
HOWEVER...A LLJ FROM THE EAST OVER THE GULF OF MEXICO WILL BRING
ONSHORE FLOW ACROSS EASTERN TO NORTHEASTERN MEXICO ON
WEDNESDAY...COMBINED WITH A STATIONARY FRONT THAT WILL POSITION
ITSELF ACROSS NORTHEASTERN MEXICO ON WEDNESDAY AND THURSDAY.
SHOWER ACTIVITY ON WEDNESDAY IS EXPECTED TO PRODUCE 10-15MM WITH
MAXIMA UP TO 35MM ACROSS SECTIONS OF HIDALGO AND BORDERING
STATES...WHILE COAHUILA...NUEVO LEON...TAMAULIPAS AND
VERACRUZ...COULD HAVE 05-10MM OF RAIN WITH MAXIMA BETWEEN 15-25MM.
ON THURSDAY...THE STATIONARY FRONT OVER NORTHEASTERN MEXICO...AND
AN UPPER TROUGH AND DIVERGENCE ALOFT WITH AN UPPER JET WILL ALLOW
FOR THUNDERSTORMS TO DEVELOP ACROSS EAST CENTRAL TO NORTHEASTERN
MEXICO. RAINFALL TOTALS OF 15-20MM WITH MAXIMA OF 25-50MM COULD BE
OBSERVED ACROSS HIDALGO...EASTERN SAN LUIS POTOSI AND
VERACRUZ...AS WELL AS THE NORTHERN PORTIONS OF TAMAULIPAS AND
NUEVO LEON...WHILE WESTERN NUEVO LEON...EASTERN COAHUILA AND
CENTRAL TO SOUTHERN TAMAULIPAS COULD OBSERVE 05-10MM WITH MAXIMA
OF 15-30MM.
CENTRAL AMERICA WILL CONTINUE TO HAVE HAVE ONSHORE WIND FLOW TODAY
AND FOR THE NEXT FEW DAYS. THE RAINFALL TOTALS DO NOT APPEAR TO BE
TOO SIGNIFICANT TODAY AND ON WEDNESDAY...WITH RAINFALL TOTALS OF
05-10MM AND MAXIMA OF 15-25MM TODAY AND WEDNESDAY ON THE CARIBBEAN
COAST OF PANAMA TO NICARAGUA. EVEN LESS RAINFALL IS EXPECTED ON
THURSDAY INTO FRIDAY...WITH ONLY A FEW BRIEF SHOWERS IN THE
FORECAST.
ACROSS NORTHERN SOUTH AMERICA...THE BIG STORY WAS DISCUSSED ABOVE
REGARDING THE WET SPELL EXPECTED FOR NORTHWESTERN PERU TO WESTERN
ECUADOR AND COLOMBIA. ELSEWHERE ACROSS NORTHERN SOUTH
AMERICA...MOSTLY OVER NORTHEASTERN PERU...SOUTHERN COLOMBIA...AND
BRAZIL...ALONG THE NET...A LARGE AREA OF CONVECTION IS FORECAST TO
PRODUCE MAINLY BETWEEN 05-15MM/DAY WITH MAXIMA UP TO 35MM TODAY
AND ON WEDNESDAY. PORTIONS OF AMAPA AND PARA COULD OBSERVE
SLIGHTLY MORE RAINFALL UP TO 45MM ON WEDNESDAY. ON
THURSDAY...NORTHEASTERN PERU AND THE WESTERN PORTIONS OF THE
AMAZONAS WILL HAVE THUNDERSTORMS...CAUSING 15-20MM WITH MAXIMA OF
25-50MM...WHILE FURTHER EAST OVER PARA...THE RAINFALL FORECAST IS
LOWER...WITH MAXIMA UP TO 35MM.
ALAMO/GALVEZ/ACOSTA...WPC (USA)
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