201
FXCA20 KWBC 241921
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
321 PM EDT MON AUG 24 2026
FORECAST BULLETIN 24 AUGUST 2026 AT 1920 UTC:
MEXICO AND NORTH CENTRAL AMERICA
ON MONDAY, THE NORTHERN PORTION OF MEXICO REMAINS UNDER SUBSIDENCE
OF A RIDGE IN THE UPPER LEVELS CENTERED OVER WEST TEXAS-UNITED
STATES, WHILE THE SOUTHERN PORTION OF THE COUNTRY IS AFFECTED BY A
STRENGTHENING UPPER TROUGH, EXPECTED TO EXTEND OVER MUCH OF
SOUTHWEST MEXICO. IN THE MID LEVELS OF THE ATMOSPHERE, THE RIDGE
OVER NORTH MEXICO IS STRONGER, SUBSIDENCE IS ACCOMPANIED BY
MID-LEVEL DRYNESS EXTENDING OVER MUCH OF NORTH MEXICO. TO THE
SOUTH, A SHORT WAVE TROUGH IS PROPAGATING WESTWARD OVER SOUTHWEST
MEXICO THROUGHOUT THE DAY ON MONDAY AND INTO EARLY TUESDAY. A
TROPICAL WAVE IS EXPECTED INTO SOUTH GUERRERO AND A SECOND WAVE IS
MAKING ITS WAY OUT INTO THE PACIFIC OCEAN. IN NORTHERN CENTRAL
AMERICA, AN UPPER LEVEL TROUGH RETROGRADES INTO THE REGION,
INTERACTING WITH RIDGING OVER THE WEST CARIBBEAN, BUT REMAINS
WEAK. IN THE MID LEVELS, THE PREVAILING EASTERLY FLOW IS
ACCOMPANIED BY DRY AIR, FUELING WEAK TRADE WIND INVERSIONS,
PRIMARILY FROM THE YUCATAN PENINSULA INTO BELIZE, EAST GUATEMALA,
AND NORTHERN HONDURAS. BY TUESDAY, THE STRENGTHENING MID TO UPPER
LEVEL TROUGH CONTINUES RETROGRADING INTO SOUTHWEST MEXICO AND INTO
THE EAST PACIFIC OCEAN, CONTINUING TO FAVOR DEEP CONVECTION IN THE
REGION WITH THE PASSING TROPICAL WAVES. IN NORTHERN CENTRAL
AMERICA, A SHIFT IN THE MID LEVEL CONDITIONS FAVORS THE ENTRY OF A
SHORTWAVE TROUGH OVER NICARAGUA, HONDURAS, AND EL SALVADOR FROM
TUESDAY INTO EARLY WEDNESDAY, AND WITH IT AN INCREASE IN MOISTURE
AS A TROPICAL WAVE PROPAGATES IN THE REGION, INTERACTING WITH THE
MOUNTAINOUS TERRAIN. BY WEDNESDAY, THE UPPER LEVEL TROUGH OVER
SOUTHWEST MEXICO ENTERS THE EAST PACIFIC OCEAN FAVORING A DECREASE
IN AVAILABLE MOISTURE FROM THE EAST AND A DECREASE IN TOTAL DAILY
PRECIPITATION IN MUCH OF THE COUNTRY. AND IN CENTRAL AMERICA, A
REORGANIZATION OF THE UPPER LEVEL TROUGH PROVIDES DIVERGENCE ALOFT
FOR CONVECTION WITH THE TROPICAL WAVE EXITING THE REGION.
CARIBBEAN AND SOUTHERN CENTRAL AMERICA
A TROPICAL WAVE CURRENTLY LOCATED OVER THE CENTRAL CARIBBEAN IS
INTERACTING WITH AN UPPER-LEVEL TROUGH EXTENDING ACROSS THE
WESTERN CARIBBEAN. THE AVAILABLE MOISTURE REMAINS UNEVENLY
DISTRIBUTED ACROSS THE REGION, WITH THE HIGHEST MOISTURE
CONCENTRATIONS GENERALLY CONFINED TO THE NORTHERN PORTIONS OF
SOUTH AMERICA AND CENTRAL AMERICA, WHILE COMPARATIVELY DRIER
CONDITIONS PERSIST ACROSS MUCH OF THE CARIBBEAN. THIS MOISTURE
DISTRIBUTION, COMBINED WITH THE EXISTING UPPER-LEVEL DYNAMICS, IS
SUPPORTING ISOLATED TO MODERATE SHOWERS AND THUNDERSTORMS,
PRIMARILY ACROSS NORTHERN AND CENTRAL PORTIONS OF SOUTH AMERICA.
ACROSS THE GREATER ANTILLES, THE UPPER-LEVEL TROUGH IS
CONTRIBUTING TO ENHANCED UPPER-LEVEL DIVERGENCE, WHICH IS FAVORING
THE DEVELOPMENT OF DEEP DIURNAL CONVECTION, PARTICULARLY OVER CUBA
AND HISPANIOLA. HOWEVER, THE RELATIVELY LIMITED MOISTURE
AVAILABILITY ACROSS PORTIONS OF THE SURROUNDING CARIBBEAN SHOULD
CONSTRAIN THE OVERALL COVERAGE AND INTENSITY OF CONVECTION OUTSIDE
THE AREAS WITH GREATER MOISTURE CONCENTRATIONS. THE CARIBBEAN
LOW-LEVEL JET IS EXPECTED TO GRADUALLY STRENGTHEN THROUGH THE
FORECAST PERIOD. THE STRENGTHENING LOW-LEVEL FLOW SHOULD
CONTRIBUTE TO INCREASED MOISTURE TRANSPORT AND ENHANCED CYCLONIC
CIRCULATION ACROSS THE PANAMA AND COSTA RICA REGION, PARTICULARLY
BY WEDNESDAY AND THURSDAY. AT THE SAME TIME, THE STRONGER
LOW-LEVEL FLOW IS EXPECTED TO PROMOTE INCREASING SUBSIDENCE AND
DRIER CONDITIONS ACROSS PORTIONS OF THE CARIBBEAN, CONTRIBUTING TO
A GRADUAL REDUCTION IN SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE
REGION. BY TUESDAY, THE TROPICAL WAVE IS FORECAST TO MOVE INTO THE
WESTERN CARIBBEAN, WHERE IT WILL CONTINUE TO INTERACT WITH A
DEEPENING UPPER-LEVEL TROUGH EXTENDING ACROSS CENTRAL AMERICA. THE
COMBINATION OF ENHANCED LOW-LEVEL CONVERGENCE, INCREASING MOISTURE
AVAILABILITY, AND FAVORABLE UPPER-LEVEL DYNAMICS SHOULD SUPPORT
THE DEVELOPMENT OF MODERATE TO STRONG SHOWERS AND THUNDERSTORMS,
PARTICULARLY ACROSS EASTERN NICARAGUA AND COSTA RICA. THE MONSOON
TROUGH EXTENDING ACROSS THE COSTA RICAâ€PANAMA BORDER WILL
FURTHER ENHANCE LOW-LEVEL CONVERGENCE AND MOISTURE POOLING ACROSS
THE REGION. CONSEQUENTLY, PERIODS OF LOCALLY HEAVY RAINFALL ARE
EXPECTED, PARTICULARLY WHERE THE MONSOON TROUGH, TROPICAL WAVE,
AND STRENGTHENING CYCLONIC CIRCULATION INTERACT. BY WEDNESDAY,
ANOTHER UPPER-LEVEL LOW-PRESSURE AREA IS EXPECTED TO MOVE ACROSS
THE NORTHERN LESSER ANTILLES AND INTERACT WITH A TROPICAL WAVE
APPROACHING THE REGION. WHILE SOME MOISTURE WILL REMAIN AVAILABLE
ACROSS THE WINDWARD ISLANDS AND NORTHERN GUIANAS, OVERALL MOISTURE
AVAILABILITY ACROSS THE EASTERN CARIBBEAN IS EXPECTED TO BECOME
INCREASINGLY LIMITED. A DRYING TREND AT THE MID-LEVELS IS ALSO
EXPECTED TO BEGIN FROM THE EAST DURING WEDNESDAY, BECOMING
INCREASINGLY EVIDENT ACROSS THE LEEWARD ISLANDS BEFORE GRADUALLY
PROGRESSING WESTWARD. THE DEVELOPING DRY AIR, SHOULD INCREASINGLY
SUPPRESS DEEP CONVECTION ACROSS THE EASTERN CARIBBEAN DURING
WEDNESDAY.
NORTHERN SOUTH AMERICA
ON MONDAY, POTENT UPPER LEVEL SYSTEMS FROM THE SOUTHERN HEMISPHERE
ARE REACHING THE SOUTHERN EXTENT OF THE FORECAST REGION, WITH A
TROUGH AXIS ENTERING SOUTH COLOMBIA/ECUADOR, AND A MID TO UPPER
LEVEL RIDGE EXTENDING INTO THE AMAZON BASIN FROM EASTERN BRASIL.
THROUGHOUT THE DAY ON MONDAY, THE MID TO UPPER LEVEL RIDGE IS
RETROGRADING INTO THE AMAZON BASIN, FAVORING DRY CONDITIONS INTO
THE REGION, AND FAVORING MOISTURE TO REMAIN ALONG THE NORTHERN
SECTORS OF COLOMBIA, VENEZUELA AND THE GUIANAS. THE PROPAGATION OF
TROPICAL WAVES INTO THE REGION WILL MOSTLY FAVOR PRECIPITATION
OVER THE NORTHERN PORTIONS OF THE REGIONS AFOREMENTIONED. ON
TUESDAY, THE DRYING TREND CONTINUES INTO THE AMAZON BASIN AND
EXTENDS NORTHWARD INTO THE GUIANAS. A TROPICAL WAVE ENTERING THE
PANAMA REGION WILL FAVOR MOIST ONSHORE FROM THE WEST INTO COLOMBIA
FROM THE PACIFIC OCEAN, FAVORING DEEP CONVECTION AND HEAVY
PRECIPITATION ON TUESDAY. BY WEDNESDAY, SIMILAR CONDITIONS COULD
PERSIST IN COLOMBIA, WHILE A GENERAL DRY TREND EXTENDS INTO
VENEZUELA AND INTO THE EASTERN AMAZON BASIN AND GUIANAS.
TROPICAL WAVES INITIALIZED AT 12 UTC:
TYP SOF 25/00 25/12 26/00 26/12 27/00 27/12 28/00 28/12
TW 15N 18W 20W 22W 25W 28W 31W 34W 37W 40W
TW 15N 41W 44W 47W 50W 53W 56W 59W 61W 63W
TW 11N 65W 69W 72W 74W 77W 80W 83W 86W 89W
TW 13N 79W 81W 83W 85W 87W 89W 92W 95W 98W
TW 17N 94W 97W 100W 104W ABS --- --- --- ---
TW 19N 105W 106W 107W 108W 109W 110W 111W 112W 113W
LUCIANO...(MDC)
CASTELLANOS...(WPC)
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