757
FXCA20 KWBC 111800
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 PM EDT WED MAR 11 2026
FORECAST BULLETIN 11 MARCH 2026 AT 1800 UTC:
AN UPPER-LEVEL TROUGH OVER NICARAGUA, EXTENDING TO THE CARIBBEAN
AT MID-LEVELS, WILL PROVIDE SOME INSTABILITY TO SUPPORT
CONVECTION, PARTICULARLY OVER HISPANIOLA, PUERTO RICO, AND
PORTIONS OF THE LESSER ANTILLES. AT LOW LEVELS, EASTERLY WINDS AND
LOW-LEVEL TROUGHS WILL ADVECT MOISTURE, SUPPORTING RAINFALL OVER
HISPANIOLA TODAY THROUGH THURSDAY, WHERE ACCUMULATIONS ARE
EXPECTED TO BE AROUND 15-25MM, THE UPPER-LEVEL TROUGH IS THEN
ANTICIPATED TO WEAKEN, RESULTING IN MORE STABLE CONDITIONS AND
LOWER PRECIPITATION TOTALS OVER THE EASTERN CARIBBEAN. HOWEVER,
UPPER-LEVEL SPEED DIVERGENCE WILL LIKELY CONTINUE OVER EASTERN
HISPANIOLA AND PUERTO RICO THROUGH FRIDAY, WHICH WILL STILL
SUPPORT THE DEVELOPMENT OF RAINFALL. EASTERLY FLOW WILL ADVECT
MOISTURE INTO HISPANIOLA, PUERTO RICO AND PORTIONS OF THE LESSER
ANTILLES FROM THURSDAY THROUGH FRIDAY, ENHANCING PASSING SHOWERS.
ADDITIONAL 15-25MM OF PRECIPITATION ARE EXPECTED FROM THURSDAY
THROUGH FRIDAY. OVERALL, PRECIPITATION ACCUMULATIONS ARE EXPECTED
TO REMAIN RELATIVELY LOW DUE TO LIMITED PRECIPITABLE WATER
AVAILABILITY IN THE REGION, BUT SHOWERS ARE LIKELY PARTICULARLY IN
THE AFTERNOON DUE TO DIURNAL HEATING AND LOCAL EFFECTS ACROSS THE
REGION.
A FRONTAL BOUNDARY IS FORECASTED TO APPROACH THE BAHAMAS AND
EXTEND INTO THE YUCATAN PENINSULA ON FRIDAY MORNING. THIS WILL
INCREASE LOW-LEVEL CONVERGENCE OVER THE NORTHERN BAHAMAS, WESTERN
CUBA, AND OVER THE YUCATAN PENINSULA AND GUATEMALA. FURTHER
UPPER-LEVEL SUPPORT IS ANTICIPATED OVER THE NORTHERN BAHAMAS WITH
AN UPPER-LEVEL TROUGH OVER THE EASTERN US ON FRIDAY, AND RAINFALL
TOTALS WILL RANGE BETWEEN 15-20MM. OVER SOUTHERN MEXICO AND
PORTIONS OF GUATEMALA, UPPER-LEVEL DIFFLUENCE WILL LIKELY SUPPORT
THE DEVELOPMENT OF THUNDERSTORMS FROM THURSDAY THROUGH FRIDAY.
THIS, IN ADDITION WITH THE PROPAGATION OF THE COLD FRONT WILL
ENHANCE ONSHORE MOISTURE ADVECTION OVER THE VERACRUZ/ REGION FROM
THURSDAY THROUGH FRIDAY, INCREASING RAINFALL ACTIVITY.
ACCUMULATIONS ARE LIKELY TO REACH 25-50MM WITH ISOLATED HIGHER
VALUES. PRECIPITATION WILL LIKELY DECREASE IN THAT AREA FROM
FRIDAY THROUGH SATURDAY AS THE LOW-LEVEL FLOW WEAKENS AND BECOMES
LESS ORGANIZED. HOWEVER, AS THE FRONTAL BOUNDARY BECOMES
STATIONARY, LOW-LEVEL MOISTURE CONVERGENCE WILL CONTINUE FROM
FRIDAY THROUGH SATURDAY, PARTICULARLY OVER SOUTHERN MEXICO AND
GUATEMALA, WHERE ADDITIONAL 15 - 30MM ARE ANTICIPATED. MID- TO
UPPER-LEVEL DIFFLUENCE WILL LIKELY ENHANCE THE DEVELOPMENT OF
THUNDERSTORMS OVER YUCATAN AND WESTERN CUBA FROM FRIDAY THROUGH
SATURDAY WITH THE PRESENCE OF A MID- TO UPPER-LEVEL TROUGH OVER
THE GULF TOWARD THE END OF THE FORECAST PERIOD.
OVER THE REST OF CENTRAL AMERICA, LIGHT PRECIPITATION IS
ANTICIPATED EACH DAY OF THE FORECAST PERIOD, MAINLY DUE TO LOCAL
EFFECTS, MOISTURE ADVECTION, DIURNAL HEATING, AND THE PRESENCE OF
LOW-LEVEL TROUGHS ENHANCING LOW-LEVEL MOISTURE CONVECTION. TOTALS
ARE ANTICIPATED TO BE RELATIVELY LOW DUE TO THE LACK OF DEEP
MOISTURE IN THE REGION AND THE ABSENCE OF MID- TO UPPER-LEVEL
SUPPORT FOR THE DEVELOPMENT OF DEEP CONVECTION IN THE AREA.
IN TROPICAL SOUTH AMERICA, THE PRESENCE OF THE BOLIVIAN HIGH AND
AN UPPER-LEVEL HIGH OVER NORTHERN SOUTH AMERICA WILL INCREASE
UPPER-LEVEL DIFFLUENCE ACROSS THE TROPICAL REGION. OVER ECUADOR
MODERATE TO HEAVY RAINFALL IS ANTICIPATED TODAY THROUGH FRIDAY,
WITH ONSHORE FLOW ADVECTING MOISTURE FROM THE PACIFIC AND
NORTHEASTERLY FLOW ADVECTING MOISTURE FROM THE AMAZON OVER THE
REGION. STARTING TODAY THROUGH THURSDAY, PRECIPITATION OVER
ECUADOR WILL RANGE FROM 20-45MM. FURTHER SUPPORT IS LIKELY WITH
THE PRESENCE OF A MID-LEVEL TROUGH OVER THE REGION, PROVIDING
ADDITIONAL INSTABILITY FOR THE DEVELOPMENT OF CONVECTIVE ACTIVITY
THROUGHOUT THE FORECAST PERIOD FROM THURSDAY THROUGH FRIDAY, AND
TOTALS ARE EXPECTED TO RANGE BETWEEN 30-60MM OVER WESTERN ECUADOR
AND NORTHWESTERN PERU, AND BETWEEN 20-35MM OVER EASTERN ECUADOR
AND THE AMAZON REGION OF PERU. ONSHORE FLOW FROM THE PACIFIC INTO
ECUADOR IS EXPECTED TO DECREASE FROM FRIDAY THROUGH SATURDAY, BUT
MOISTURE ADVECTION FROM THE AMAZON WILL CONTINUE TO SUPPORT
SHOWERS IN THE AREA.
ANOTHER AREA OF INTEREST IS THE GUIANAS AND NORTHERN BRAZIL, AS A
PLUME OF MOISTURE CONTINUES TO BE ADVECTED BY EASTERLY LOW-LEVEL
FLOW, AND A SERIES OF LOW-LEVEL TROUGHS HELP TO INCREASE LOW-LEVEL
MOISTURE CONVERGENCE. THE HEAVIEST PRECIPITATION IS ANTICIPATED
FROM TODAY THROUGH FRIDAY, AS AN UPPER-LEVEL TROUGH OVER THE
NORTHEASTERN COAST OF BRAZIL WILL ENHANCE UPPER-LEVEL DIVERGENCE
OVER THE GUIANAS AND BRAZIL. ACCUMULATIONS ARE LIKELY TO EXCEED
50MM EACH DAY. LESS PRECIPITATION IS EXPECTED FROM FRIDAY THROUGH
SATURDAY.
LOW-LEVEL CONVERGENCE IS EXPECTED OVER THE EASTERN AND CENTRAL
AMAZON, WHICH, COMBINED WITH DEEP MOISTURE IN THE REGION, WILL
PROVIDE ENOUGH INSTABILITY FOR THE DEVELOPMENT OF THUNDERSTORMS
AND STRONG RAINFALL FROM TODAY THROUGH FRIDAY. AS THE LOW-LEVEL
FLOW IS EXPECTED TO BECOME MORE EASTERLY ON FRIDAY, THE LOW-LEVEL
CONVERGENCE WILL ENHANCE PRECIPITATION OVER THE CENTRAL AMAZON
BASIN, ALTHOUGH UPPER-LEVEL DIFFLUENCE OVER THE EASTERN AMAZON
BASIN WILL CONTINUE TO SUPPORT THUNDERSTORMS IN THAT REGION.
RIVERA-TORRES...(WPC)
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