558
FXCA20 KWBC 311843
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT TUE MAR 31 2026
FORECAST BULLETIN 31 MARCH 2026 AT 1845 UTC:
MEXICO AND NORTH CENTRAL AMERICA...
AN UPPER LEVEL TROUGH IS SITUATED OVER MEXICO WITH ITS BASE OVER
THE EAST PACIFIC ON TUESDAY MORNING. THE SUBTROPICAL JET IS
LOCATED ON THE DIVERGENT SIDE OF THE UPPER LEVEL TROUGH, EXTENDING
FROM SOUTHERN MEXICO AND THROUGH THE NORTH CARIBBEAN, AND
INTERACTS WITH THE RIDGING OVER THE CARIBBEAN SEA AND SOUTH
CENTRAL AMERICA. THIS PATTERN IS REFLECTED IN THE MID-LEVELS,
WHERE SHORTWAVE TROUGHS ARE PROPAGATING IN THE PERIPHERY OF THE
MID TO UPPER TROUGH, FAVORING LIFT OVER SOUTHERN MEXICO ON
TUESDAY, AND THEN IN THE YUCATAN PENINSULA, AND NORTHERN CENTRAL
AMERICA ON WEDNESDAY. IN THE LOWER LEVELS, MOIST AIR IS ADVECTED
ALONG THE TRADE WINDS WITH THE PRESENCE OF MOIST PLUMES ENTERING
THE YUCATAN PENINSULA AND NORTHERN CENTRAL AMERICA ON TUESDAY AND
WEDNESDAY. WITH THE UPPER LEVEL SUPPORT, EXPECT MODERATE
PRECIPITATION ON TUESDAY AND WEDNESDAY, AS WELL AS THE RISK OF
SEVERE WEATHER IN NORTH CENTRAL AMERICA AND PORTIONS OF THE
YUCATAN PENINSULA, PARTICULARLY ON WEDNESDAY. BY THURSDAY, THE
UPPER LEVEL TROUGH IS EXPECTED TO PROPAGATE EAST INTO THE WESTERN
CARIBBEAN BY THURSDAY EVENING, DECREASING THE DIVERGENCE IN THE
REGION, AND DECREASING THE TOTAL PRECIPITATION FOR THE DAY TO
LIGHT AMOUNTS.
CARIBBEAN...
A RIDGING PATTERN IS IN EFFECT IN THE UPPER LEVELS OVER MUCH OF
THE CARIBBEAN, WHICH IS REFLECTED MOSTLY IN THE WESTERN SIDE OF
THE CARIBBEAN IN THE MID LEVELS. MOISTURE OVER THE REGION REMAINS
LOW, WITH THE EXCEPTION OF THE PROPAGATION OF MOIST PLUMES THAT
ARE EMBEDDED IN THE TRADE WINDS, MAKING THEIR WAY DAILY ON TUESDAY
AND WEDNESDAY. EXPECT THIS PATTERN TO FAVOR LIGHT TOTALS OF
PRECIPITATION. THE PATTERN BEGINS TO SHIFT FROM LATE WEDNESDAY
INTO THURSDAY AS THE UPPER LEVEL TROUGH OVER MEXICO AND NORTH
CENTRAL AMERICA PROPAGATES INTO THE WESTERN CARIBBEAN, WITH ITS
DIVERGENT SIDE OVER WEST CUBA AND EXTENDING EASTWARD THROUGHOUT
THE DAY ON THURSDAY. THIS WILL FAVOR A MARGINAL RISK OF SEVERE
WEATHER ON THURSDAY IN WESTERN CUBA. IN TERMS OF PRECIPITATION,
MUCH OF THE TOTALS ARE EXPECTED TO REMAIN LIGHT TO MODERATE, AS
THE AMOUNTS OF AVAILABLE MOISTURE REMAINS LOW IN THE AREA,
ALTHOUGH UPPER LEVEL SUPPORT IS PRESENT.
SOUTHERN CENTRAL AMERICA...
MUCH OF THE SUPPORT FOR PRECIPITATION IN THE REGION WILL BE DUE TO
LOW LEVEL MOISTURE CONVERGENCE THAT WILL BE DECREASING OVER THE
NEXT THREE DAYS. ON TUESDAY, THE MOIST ONSHORE FLOW EXTENDING FROM
THE CARIBBEAN SEA AND REACHING THE EASTERN COASTS OF COSTA RICA
AND PANAMA WILL BE PRESENT, AS WELL AS LOW LEVEL CYCLONIC
CIRCULATION ON THE PACIFIC COASTS OF COSTA RICA AND PANAMA. THE
AVAILABLE MOISTURE IN THE REGION WILL EXCEED 50MM AND PROVIDE FUEL
FOR LIGHT TO MODERATE AMOUNTS OF PRECIPITATION ON TUESDAY. THE
PRECIPITABLE WATER VALUES ON WEDNESDAY ARE EXPECTED TO DECREASE,
PARTICULARLY ON THE CARIBBEAN COASTS OF SOUTH CENTRAL AMERICA,
FAVORING A DECREASE IN TOTAL PRECIPITATION VALUES ON WEDNESDAY. BY
THURSDAY, ALTHOUGH MODEL GUIDANCE IS SUGGESTING AN INCREASE IN
MOISTURE IN THE CARIBBEAN COASTS OF THE REGION, THE SPEED OF THE
ONSHORE FLOW IN THE LOW LEVELS IS NOT EXPECTED TO REMAIN LOW, AND
THUS NOT ENHANCE OROGRAPHIC LIFT ALONG THE EASTERN SHORES OF THE
REGION, FAVORING LIGHT PRECIPITATION ON THURSDAY.
NORTH SOUTH AMERICA...
SINCE THE BEGINNING OF THE WORK WEEK, AN ATMOSPHERIC KELVIN WAVE
IS PROPAGATING OVER THE TROPICAL REGION OF SOUTH AMERICA,
ENHANCING UPPER LEVEL DIVERGENCE AS IT CONTINUES ITS EASTWARD
TRAJECTORY. THERE ARE LARGE SCALE UPPER LEVEL RIDGES THAT SURROUND
THE REGION, WITH THE BOLIVIAN HIGH TO THE SOUTH, A RETROGRADING
UPPER RIDGE IN THE CENTRAL ATLANTIC, AND ANOTHER RIDGE OVER THE
EASTERN PACIFIC, WHICH MAKES THE NORTHWEST SOUTH AMERICA REGION AN
AREA OF DIFFLUENCE BETWEEN THESE SYSTEMS. THIS PATTERN IS EXPECTED
TO REMAIN IN PLACE FOR THE NEXT THREE DAYS AND WILL FAVOR DEEP
CONVECTION OVER THE AMAZON REGION. IN THE LOWER LEVELS, THE TRADE
WINDS ARE CONVERGING OVER THE AMAZON BASIN, WITH SOME REGIONS
REACHING PRECIPITABLE WATER VALUES EXCEEDING 55MM IN THE REGION.
THE AREAS OF HEAVIEST PRECIPITATION ARE EXPECT IN THE EASTERN AND
CENTRAL AMAZON BASIN ON TUESDAY AND WEDNESDAY. BY THURSDAY, THE
AREAS OF STRONGEST LOW LEVEL MOISTURE CONVERGENCE IS EXPECTED OVER
THE WESTERN AMAZON BASIN, WHERE EXPECT HEAVY PRECIPITATION TOTALS.
CASTELLANOS...(WPC)
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