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FXCA20 KWBC 131843
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT WED MAY 13 2026
CORRECTED VERSION:
FORECAST BULLETIN 13 MAY 2026 AT 1825 UTC:
ACROSS MEXICO...
A LOW LEVEL TROUGH WILL BE PRESENT ACROSS THE SOUTHERN GULF REGION
ON WEDNESDAY AND THURSDAY AND IT WILL SUPPORT MOISTURE CONVERGENCE
AND ENHANCED LOW LEVEL CYCLONIC CIRCULATION. THERE WILL ALSO BE
MOISTURE POOLING DUE TO THE INTERACTION BETWEEN THE NORTH TO
NORTHEASTERLY LOW LEVEL WINDS AND THE LOCAL TOPOGRAPHY. MODERATE
TOTAL PRECIPITATION MAXIMA ARE LIKELY IN TABASCO AND NORTH
CHIAPAS. ALONG THE WEST COAST, EXPECT DAILY SHOWERS AND
THUNDERSTORMS DUE TO THE PRESENCE OF LOW LEVEL ONSHORE FLOW AND
HIGH PRECIPITABLE WATER VALUES. EXPECT DAILY MODEST TOTAL
PRECIPITATION MAXIMA IN THIS REGION THROUGH THE FORECAST CYCLE.
ACROSS THE REST OF THE COUNTRY, EXPECT STABLE CONDITIONS TO
PREVAIL DUE TO THE PRESENCE OF A MID-TO-UPPER LEVEL RIDGE.
IN THE BAHAMAS, CARIBBEAN, AND CENTRAL AMERICA...
A WEAKENING COLD FRONT WILL BE TO THE NORTH OF THE BAHAMAS AND IT
WILL FAVOR THE INCREASE IN SOUTHWESTERLY LOW LEVEL WINDS ACROSS
CUBA AND THE SOUTHEAST BAHAMAS FOR WEDNESDAY AND THURSDAY. THE
INCREASE IN PRECIPITABLE WATER AND LOCAL EFFECTS WILL SUPPORT
MODEST TOTAL PRECIPITATION MAXIMA IN THE REGION FROM WEDNESDAY
MORNING THROUGH THURSDAY MORNING. ON THURSDAY, EXPECT THE
AMPLIFICATION OF AN UPPER LEVEL TROUGH WHOSE AXIS WILL EXTEND INTO
CENTRAL AMERICA ON FRIDAY. SPEED DIVERGENCE WILL BE PRESENT ACROSS
CUBA AND THE BAHAMAS. THE AFOREMENTIONED CONDITIONS WILL FAVOR
MODERATE TOTAL PRECIPITATION MAXIMA FROM THURSDAY MORNING THROUGH
FRIDAY MORNING IN CUBA AND THE BAHAMAS. BY FRIDAY, EASTERLY LOW
LEVEL WINDS WILL AGAIN DOMINATE IN THE GREATER ANTILLES AND
BAHAMAS AND LOCALLY INDUCED TROUGHS WILL FAVOR THE INCREASE IN
PRECIPITATION CHANCES.
ON WEDNESDAY, A LOW LEVEL TROUGH WILL BE MOVING WEST OF THE ANDES
IN NORTHERN COLOMBIA THAT WILL HELP INCREASE PRECIPITATION CHANCES
IN THE REGION. IT WILL FAVOR MODERATE TOTAL PRECIPITATION MAXIMA
THROUGH THURSDAY MORNING. THEREAFTER, THE AFOREMENTIONED UPPER
TROUGH WILL EXTEND INTO THE SOUTHERN CARIBBEAN SEA AND IT WILL
SUPPORT UPPER DIVERGENCE ACROSS COSTA RICA, PANAMA, AND COLOMBIA.
WITH THE ARRIVAL OF THE UPPER TROUGH, EXPECT THE DEVELOPMENT OF A
SURFACE-TO-MID LEVEL TROUGH THAT WILL ENHANCE CYCLONIC ROTATION.
MEANWHILE, PRECIPITABLE WATER VALUES WILL EXCEED 50MM. THESE
CONDITIONS WILL SUPPORT ENHANCED TOTAL PRECIPITATION MAXIMA FOR
FRIDAY IN COLOMBIA AND MODERATE TOTAL PRECIPITATION MAXIMA
ELSEWHERE.
ELSEWHERE IN THE REGION, SEASONAL CONDITIONS WILL PREVAIL FOR THE
NEXT THREE DAYS.
IN TROPICAL SOUTH AMERICA...
A LOW LEVEL TROUGH THAT WILL BE EMBEDDED WITHIN A STRONG MOISTURE
PLUME, WHICH WILL CONTAIN PRECIPITABLE WATER VALUES IN EXCESS FOR
50MM, WILL BE MOVING INTO THE AMAZON DELTA AND GUIANAS ON
WEDNESDAY. AT THE SAME TIME, EXPECT A DIFFLUENT UPPER LEVEL
PATTERN THAT WILL SUPPORT UPPER DIVERGENCE AND THE DEVELOPMENT OF
MID-LEVEL SHORTWAVE TROUGHS. STARTING THURSDAY, THE UPPER LEVEL
SUPPORT WILL DIMINISH THOUGH THE MID-LEVEL SHORTWAVE TROUGHS WILL
REMAIN IN THE REGION THROUGH THE FORECAST CYCLE. THE LOW LEVEL
TROUGH WILL CONTINUE TO MOVE ACROSS THE GUIANAS AND INTO VENEZUELA
FOR THURSDAY AND FRIDAY, THOUGH THE MOISTURE PLUME WILL WEAKEN.
REGARDLESS, PRECIPITABLE WATER VALUES WILL REMAIN HIGH. THUS,
EXPECT THE MOST INTENSE TOTAL PRECIPITATION MAXIMA FOR WEDNESDAY
AND MODERATE TOTAL PRECIPITATION MAXIMA IN THE VICINITY OF THIS
LOW LEVEL TROUGH ON THURSDAY AND FRIDAY. MEANWHILE IN THE
NORTHWEST AMAZON BASIN, EXPECT A MOISTENING TREND THROUGH THE END
OF THE WEEK, PRIMARILY DUE TO THE RESURGENCE OF EASTERLY LOW LEVEL
WINDS. THUS, EXPECT ENHANCED TOTAL PRECIPITATION MAXIMA FOR
FRIDAY.
TINOCO-MORALES...(WPC)
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