546
FXCA20 KWBC 121809
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
209 PM EDT THU MAR 12 2026
FORECAST BULLETIN 12 MARCH 2026 AT 1800 UTC:
A WEAKENING UPPER-LEVEL TROUGH OVER THE CARIBBEAN WILL CONTINUE TO
AID THE DEVELOPMENT OF THUNDERSTORMS TODAY THROUGH FRIDAY,
PARTICULARLY OVER HISPANIOLA, PUERTO RICO, AND THE LEEWARD
ISLANDS. ALTHOUGH THE UPPER-LEVEL TROUGH IS EXPECTED TO WEAKEN BY
FRIDAY, SOME SPEED DIVERGENCE IS LIKELY TO CONTINUE OVER PUERTO
RICO AND THE LESSER ANTILLES, SUPPORTING CONVECTIVE ACTIVITY FROM
FRIDAY THROUGH SATURDAY. OVER THE LEEWARD ISLANDS AND PUERTO RICO,
A LOW-LEVEL TROUGH WILL AID MOISTURE ADVECTION THROUGH FRIDAY
AFTERNOON, SUPPORTING THE DEVELOPMENT OF SHOWERS. ACCUMULATIONS
ARE EXPECTED TO BE AROUND 15-25MM FROM TODAY THROUGH FRIDAY, AND
AN ADDITIONAL 15-20MM IS EXPECTED FROM FRIDAY THROUGH SATURDAY.
THE LOW-LEVEL TROUGH AND HIGHER VALUES OF PWAT ARE ANTICIPATED TO
REACH HISPANIOLA AND JAMAICA ON SATURDAY, WHICH, COMBINED WITH
LOCAL EFFECTS, WILL BRING SOME SHOWERS TO THE AREA. A MID-LEVEL
HIGH, HOWEVER, IS ANTICIPATED TO DEVELOP OVER THE CARIBBEAN ON
SATURDAY, BRINGING MORE STABLE CONDITIONS TO THE REGION THROUGH
THE END OF THE FORECAST PERIOD.
A FRONTAL BOUNDARY CURRENTLY EXTENDING FROM THE EASTERN US INTO
VERACRUZ IS EXPECTED TO INCREASE RAINFALL ACTIVITY OVER THE
NORTHERN BAHAMAS, CUBA, AND PORTIONS OF MEXICO AND CENTRAL AMERICA
THROUGH SATURDAY, PRIMARILY AS A RESULT OF ENHANCED LOW-LEVEL
MOISTURE CONVERGENCE. MOST OF THE PRECIPITATION ASSOCIATED WITH
THE FRONTAL BOUNDARY IS ANTICIPATED TO START TODAY THROUGH FRIDAY
MORNING, PARTICULARLY OVER VERACRUZ, TABASCO, AND THE YUCATAN
PENINSULA. ACCUMULATIONS OF PRECIPITATION OVER THE VERACRUZ AND
TABASCO BORDER ARE ANTICIPATED TO REACH 35-70MM TODAY THROUGH
FRIDAY MORNING, AS AN ENHANCEMENT IN PRECIPITATION IS LIKELY WITH
THE DEVELOPMENT OF THE TEHUANTEPECER LOW-LEVEL JET AND UPPER-LEVEL
DIFFLUENCE IN THE REGION. OVER THE YUCATAN PENINSULA, GUATEMALA,
AND BELIZE, TOTALS WILL RANGE BETWEEN 20-35MM. THE FRONTAL
BOUNDARY IS THEN EXPECTED TO BECOME NEARLY STATIONARY AND START TO
WEAKEN FROM FRIDAY THROUGH SATURDAY, BUT LOW-LEVEL MOISTURE
CONVERGENCE WILL PERSIST OVER GUATEMALA AND BELIZE, AND TOTALS ARE
ANTICIPATED TO RANGE BETWEEN 20-45MM. ADDITIONALLY, STRONG
UPPER-LEVEL WINDS WILL SUPPORT STRONG CONVECTION OVER THE YUCATAN
PENINSULA, WESTERN CUBA, AND THE NORTHERN BAHAMAS FROM FRIDAY
AFTERNOON THROUGH SATURDAY. AN UPPER-LEVEL TROUGH WILL ALSO
APPROACH THE GULF ON SUNDAY, MAINTAINING STRONG CONVECTION IN THE
AREA.
OVER MOST OF CENTRAL AMERICA, CONDITIONS ARE EXPECTED TO REMAIN
FAIRLY STABLE THROUGHOUT THE FORECAST PERIOD, MOSTLY DUE TO DRY
CONDITIONS DOMINATING THE REGION. LIGHT RAINFALL CAN BE EXPECTED,
WITH TOTAL DAILY ACCUMULATIONS AROUND 15MM WITH THE PRESENCE OF
WEAK LOW-LEVEL TROUGHS, SLIGHT INCREASES IN PRECIPITABLE WATER,
DIURNAL HEATING, AND OTHER LOCAL EFFECTS.
IN TROPICAL SOUTH AMERICA, HEAVY PRECIPITATION IS EXPECTED TODAY
THROUGH FRIDAY OVER THE GUIANAS AND THE EASTERN AMAZON BASIN IN
BRAZIL, WITH TOTALS REACHING 40-80MM DUE TO THE PRESENCE OF A
PLUME OF MOISTURE EAST OF THE CONTINENT, LOW-LEVEL FLOW
CONVERGENCE, AND THE PROPAGATION OF A LOW-LEVEL TROUGH INCREASING
INSTABILITY IN THE REGION. FURTHER SUPPORT FOR THE DEVELOPMENT OF
THUNDERSTORMS AND CONVECTIVE ACTIVITY IS ANTICIPATED WITH
MID-LEVEL SHORTWAVE TROUGHS AND UPPER-LEVEL DIFFLUENCE. AS THE
LOW-LEVEL TROUGH PROPAGATES AND MOISTURE CONTINUES TO BE ADVECTED
INTO THE REGION, PRECIPITATION WILL REMAIN HIGH IN THE AREA AND
REACH THE CENTRAL AMAZON BASIN IN BRAZIL AND EASTERN VENEZUELA.
HEAVY PRECIPITATION IS ALSO EXPECTED OVER ECUADOR TODAY THROUGH
FRIDAY MORNING WITH DEEP MOISTURE BEING ADVECTED FROM THE AMAZON
REGION AND LOW-LEVEL FLOW CONVERGING IN THE AREA. ADDITIONALLY,
FLOW PERPENDICULAR TO THE PACIFIC COAST OF ECUADOR WILL BRING
MOISTURE ONSHORE. TOTALS ARE FORECASTED TO RANGE BETWEEN 40-80MM.
THUNDERSTORMS AND STRONG SHOWERS WILL CONTINUE FROM FRIDAY THROUGH
SUNDAY OVER ECUADOR AND WILL INCREASE OVER PERU, AS A MID-LEVEL
TROUGH DEVELOPS IN THE REGION AND UPPER-LEVEL DIFFLUENCE
INCREASES, FURTHER ENHANCING CONVECTIVE ACTIVITY.
RIVERA-TORRES...(WPC)
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