061
FXCA20 KWBC 201808
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
107 PM EST THU NOV 20 2025
FORECAST BULLETIN 20 NOVEMBER 2025 AT 1800 UTC:
MEXICO, CENTRAL AMERICA, THE BAHAMAS, AND THE CARIBBEAN:
A SERIES OF UPPER-LEVEL TROUGHS, EACH REFLECTED DOWN TO THE
MID-LEVELS, ARE EXPECTED TO MAKE THEIR WAY THROUGH THE NORTHERN
REGION OF BAJA CALIFORNIA AND SONORA THROUGHOUT THE NEXT THREE
DAYS. THE FIRST TROUGH WILL PASS THROUGH NORTHERN MEXICO AND ENTER
THE SOUTHWEST UNITED STATES TODAY, WHILE ANOTHER UPPER-LEVEL
TROUGH, IN THE FORM OF A CUTOFF LOW, IS EXPECTED TO ARRIVE INTO
THE BAJA CALIFORNIA REGION ON FRIDAY. IN THE LOWER LEVELS, A COLD
FRONT WILL ENTER BAJA CALIFORNIA FROM THE PACIFIC ON FRIDAY
MORNING BEFORE THE ARRIVAL OF ANOTHER COLD FRONT ON SATURDAY
MORNING, BRINGING PRECIPITATION FROM FRIDAY MORNING UNTIL SUNDAY
MORNING. THE SUBSEQUENT COLD FRONT WILL BECOME ABSORBED INTO THE
PRIMARY FRONT BEFORE ALSO MOVING INTO THE SOUTHWEST UNITED STATES.
THE HEAVIEST PRECIPITATION IS EXPECTED TO OCCUR IN NORTHERN BAJA
CALIFORNIA ON SATURDAY, WITH A MAXIMUM OF 25-50MM EXPECTED. ON
SUNDAY, HEAVY PRECIPITATION WILL CONTINUE, AND A MAXIMUM OF
20-45MM IS EXPECTED.
IN COSTA RICA AND PANAMA, THE PRESENCE OF THE PANAMANIAN LOW WILL
CONTINUE TO ALLOW MOISTURE TO FUNNEL ONSHORE INTO THE ATLANTIC
COAST THROUGHOUT THE NEXT THREE DAYS. WITH A SUBTLE BUT PRESENT
LOW-LEVEL JET, WITH WINDS AROUND AND EXCEEDING 15KTS, INCOMING
MOISTURE WILL BE OROGRAPHICALLY LIFTED BY THE HIGH TERRAIN, WHICH
WILL YIELD LOCALLY HIGH TOTALS IN THE REGION.
IN NICARAGUA AND HONDURAS, AN UPPER-LEVEL TROUGH WILL DEVELOP ON
FRIDAY, WHILE IN THE MID-LEVELS, REFLECTION OF THE TROUGH IN THE
FORM OF AN INVERTED TROUGH IS EXPECTED TO DEVELOP LATER INTO THE
WEEKEND. IN THE LOWER LEVELS, A TROUGH WITH SUBTLE MOISTURE BEING
BROUGHT IN FROM THE PANAMANIAN LOW WILL RESULT IN LIGHT
PRECIPITATION ON SATURDAY AND SUNDAY, WITH HIGHER AMOUNTS POSSIBLE
IN LOCALIZED AREAS. MAXIMA OF 15-25MM ARE EXPECTED FOR BOTH
SATURDAY AND SUNDAY FOR THE EAST COAST OF NICARAGUA AND EAST
HONDURAS.
IN THE BAHAMAS AND THE CARIBBEAN, A LARGE AND POTENT AREA OF HIGH
PRESSURE WILL CONTINUE TO REMAIN IN PLACE AND PREVENT ANY
ORGANIZED PRECIPITATION FROM FORMING. ANY PRECIPITATION IN THIS
REGION WILL BE LOCALIZED, PARTICULARLY IN HISPANIOLA, WITH
MOISTURE BEING BROUGHT IN FROM THE MID-LATITUDE FRONTAL SYSTEMS
PASSING THROUGH INTO THE ATLANTIC, NORTH OF THE BAHAMAS.
TROPICAL SOUTH AMERICA:
IN WESTERN COLOMBIA, THE DEVELOPMENT OF THE PANAMANIAN LOW WILL
DEVIATE MUCH OF THE MOISTURE AWAY FROM THE COAST TODAY AND FRIDAY,
BEFORE REDIRECTING ITSELF BACK INTO A WESTERLY ONSHORE FLOW ON
SATURDAY. PRECIPITATION IN THIS REGION WILL BECOME HEAVIER ON
SATURDAY, WITH TOTALS REACHING A MAXIMUM OF 25-50MM. IN TRINIDAD
AND TOBAGO, AND NEARBY REGIONS OF NORTHERN SOUTH AMERICA, A LONG
FETCH PLUME OF MOISTURE FROM WITH THE ITCZ WILL ADVECT INTO THE
REGION FROM THE EAST. WITH PROLONGED 15KT FLOW IN THE LOW LEVELS
ALONG WITH SUFFICIENT PRECIPITABLE WATER AVAILABLE, PRECIPITATION
IS EXPECTED TO OCCUR DAILY FOR THE NEXT THREE DAYS. PRECIPITATION
MAXIMA OF 15-30MM ARE EXPECTED OVER THE WEEKEND FOR THIS REGION.
IN THE INTERIOR REGIONS OF TROPICAL SOUTH AMERICA, MOISTURE
AVAILABILITY WILL INCREASE LATE INTO THE WEEKEND AND MOVE FROM THE
EASTERN PORTIONS OF THE AMAZON. THIS MOISTURE WILL PROVIDE FUEL
FOR CONVECTION DUE TO LOCALIZED, DIURNAL, AND OROGRAPHIC EFFECTS,
WITH THE HEAVIEST PRECIPITATION OCCURRING ON SATURDAY IN SOUTHERN
VENEZUELA, NORTHWEST BRAZIL, AND EASTERN COLOMBIA.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYP SOF INIT 21/00 21/12 22/00 22/12 23/00 23/12 24/00
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