980
FXCA20 KWBC 111856
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EDT THU SEP 11 2025
FORECAST BULLETIN 10 SEPTEMBER 2025 AT 1930 UTC:
SYNOPSIS:
DIURNAL AND LOCALLY INDUCED CONVECTION WILL CONTINUE TO BE THE
MAIN CATALYST FOR PRECIPITATION IN THE REGION THROUGHOUT THE NEXT
FEW DAYS, ESPECIALLY ACROSS THE CARIBBEAN AND SOUTH AMERICA. IN
THE MID TO UPPER LEVELS, A DEEP TROUGH IS DIGGING INTO THE GULF,
AND IN THE LOWER LEVELS, A STATIONARY FRONT WILL REMAIN IN PLACE
AFFECTING THE BAHAMAS AND PARTS OF THE GREATER ANTILLES THROUGH
THE REST OF THE WEEK AND INTO THE WEEKEND. THE NATIONAL HURRICANE
CENTER CONTINUES TO MONITOR A POTENTIAL TROPICAL CYCLONE TO THE
SOUTH OF MEXICO, AND HAS GIVEN IT A 90% CHANCE OF DEVELOPING IN
THE NEXT TWO DAYS. THE INFLUENCE OF THE PANAMANIAN LOW WILL BE OF
INTEREST FOR COSTA RICA AND PANAMA OVER THE COMING DAYS, WITH
HEAVY PRECIPITATION EXPECTED THROUGHOUT MUCH OF THE WEEKEND. THIS
WILL ALSO BRING DAILY RAINFALL TO THE WEST COAST OF COLOMBIA AS AN
ABUNDANCE OF MOISTURE IS ADVECTED IN, WITH LOW-LEVEL FLOW ALLOWING
IT TO MOVE ONSHORE. PRECIPITATION IS ALSO EXPECTED FOR THE
WINDWARD PARTS OF THE SOUTH AMERICAN MOUNTAIN RANGES OF COLOMBIA
AND VENEZUELA, WITH DRIER AIR ADVECTING INTO THE NORTHERN PORTION
OF THE CONTINENT OVER THE WEEKEND.
MEXICO AND CENTRAL AMERICA:
THE MAIN AREA OF INTEREST IN MEXICO IS TO THE SOUTH AND WEST,
WHERE THERE ARE POTENTIAL IMPACTS POSSIBLE ALONG THE SOUTHERN
COAST, TO INCLUDE JALISCO, COLIMA, MICHOACĂN, AND GUERRERO, DUE
TO A TROPICAL WAVE IN THE EAST PACIFIC , WHICH IS EXPECTED TO
BECOME A TROPICAL CYCLONE IN THE COMING DAYS. THERE IS STILL
UNCERTAINTY AS TO HOW CLOSE THIS SYSTEM WILL GET TO THE COAST, BUT
REGARDLESS, THE PROXIMITY OF THE SYSTEM IS STILL EXPECTED TO
PROVIDE AMPLE MOISTURE TO THE REGION, AND LOCALLY INDUCED
THUNDERSTORMS WITH TOTALS OF UP TO 20-45MM ARE EXPECTED DAILY
THROUGH SATURDAY.
IN EAST MEXICO, A DEEP UPPER LEVEL TROUGH CONTINUES TO ENCROACH
INTO THE GULF AND EXTEND AS FAR DOWN AS THE YUCATĂN PENINSULA,
WITH ADDITIONAL SUPPORT IN THE MID-LEVELS BY WAY OF AN INVERTED
TROUGH. GIVEN THE UPPER-LEVEL DIVERGENCE AND LOW-LEVEL MOISTURE
ADVECTION ENTERING ONSHORE FROM THE ATLANTIC, HEAVY PRECIPITATION
OF UP TO 20-45MM ON FRIDAY, AND UP TO 30-60MM ON SATURDAY IS
EXPECTED, PARTICULARLY AFFECTING CAMPECHE, TABASCO, AND SOUTHEAST
VERACRUZ. LOWER TOTALS ASSOCIATED WITH THIS SAME SETUP ARE ALSO
EXPECTED IN BELIZE AND GUATEMALA, WITH UP TO 20-45MM ON FRIDAY AND
20-35MM ON SATURDAY.
IN NICARAGUA AND HONDURAS, THE MAIN PRECIPITATION EVENT WILL OCCUR
ON SUNDAY CAUSED BY A LOW-LEVEL TROUGH WITH ORIGINS NEAR THE
MONSOON TROUGH IN COSTA RICA/PANAMA. WITH SUPPORT OF A MID-LEVEL
TROUGH AND SUFFICIENT MOISTURE ADVECTION BEING INFLUENCED BY THE
PANAMANIAN LOW, MAXIMUM PRECIPITATION WILL BE AROUND 15-25MM ON
SUNDAY, WITH LOCALLY HEAVIER AMOUNTS POSSIBLE. ON FRIDAY AND
SATURDAY, ANY POSSIBLE CONVECTION WILL BE INHIBITED AND
PRECIPITATION WILL BE LIGHT DUE TO AN INTRUSION OF SAHARAN DUST.
IN COSTA RICA AND PANAMA, THE PANAMANIAN LOW IS FORECAST TO
INFLUENCE MUCH OF THE RAINFALL OVER THE WEEKEND. MAX RAINFALL
TOTALS OF UP TO 25-50MM ON SATURDAY AND 30-60MM ON SUNDAY ARE
EXPECTED, WITH POTENTIALLY HIGHER AMOUNTS POSSIBLE IN ISOLATED
AREAS.
BAHAMAS AND THE CARIBBEAN:
THE STATIONARY FRONT IN THE ATLANTIC, FLORIDA, AND THE NORTHERN
ISLANDS OF THE BAHAMAS IS EXPECTED TO REMAIN IN PLACE FOR THE NEXT
FEW DAYS, BRINGING MODERATE PRECIPITATION OF UP TO 15-30MM TO THE
BAHAMAS EACH DAY THROUGH THE FORECAST PERIOD. THE AFOREMENTIONED
DEEP TROUGH DIGGING INTO THE GULF, ALONG WITH A LOW-LEVEL TROUGH
ASSOCIATED WITH THE STATIONARY FRONT SHOULD AID IN BRINGING
MOISTURE INTO CUBA. ALONGSIDE OROGRAPHIC EFFECTS, THIS SHOULD AID
IN THE DEVELOPMENT OF CONVECTION EACH DAY, WITH DAILY RAINFALL
AMOUNTS REACHING UP TO 15-25MM. IN HISPANIOLA, DRY AIR IS EXPECTED
TO INTRUDE ON FRIDAY AND SATURDAY DUE TO A PLUME OF SAHARAN DUST,
AND ANY PRECIPITATION THAT FALLS WILL BE LOCALIZED DUE TO THE
ASSOCIATED GENERAL LACK OF MOISTURE. ON SUNDAY, HOWEVER, THE
MAJORITY OF THE DRY AIR PLUME WILL HAVE PROGRESSED WESTWARD AND
CLEARED THE ISLAND, AND WITH SUPPORT FROM THE LOW-LEVEL TROUGH
ASSOCIATED WITH THE STATIONARY FRONT, LOCALIZED CONVECTION WILL
RESUME. FOR THE LESSER ANTILLES, THERE IS A TROPICAL WAVE LOCATED
AT 52W FORECAST TO ENTER THE ISLANDS ON SUNDAY, AND PRECIPITATION
OF UP TO 15-25MM IS EXPECTED.
TROPICAL SOUTH AMERICA:
THE BROAD CIRCULATION OF THE PANAMANIAN LOW IN CENTRAL AMERICA
WILL HELP TO BRING SIGNIFICANT AMOUNTS OF MOISTURE NEAR THE WEST
COAST OF COLOMBIA EACH DAY IN THE FORECAST PERIOD. WITH WEAK
LOW-LEVEL FLOW, THE HIGHEST TOTALS OF THE PRECIPITATION IS LIKELY
TO OCCUR OVER THE OCEAN, HOWEVER, GIVEN THE ORTHOGONAL FLOW TO THE
COAST, PRECIPITATION IN COLOMBIA IS STILL LIKELY. THE HIGHEST
TOTAL PRECIPITATION OVER COLOMBIA IS EXPECTED TO OCCUR ON
SATURDAY, WITH UP TO 25-50MM. MOISTURE IS ALSO EXPECTED TO
CONVERGE ON THE EASTERN SIDE OF THE CORDILLERA, WHICH WILL RESULT
IN SEASONAL PRECIPITATION FOR THIS TIME OF YEAR THROUGHOUT THE
WEEKEND. MAXIMUM PRECIPITATION IN THIS REGION SHOULD BE AROUND
20-35MM EACH DAY. FURTHER EAST, A PLUME OF DRY AIR IS ANTICIPATED
TO COME INTO THE NORTH OF BRAZIL, AND THE GUIANAS ON FRIDAY AND
SATURDAY. ANY PRECIPITATION IN THIS REGION DURING THAT TIME WILL
BE MODEST AND IN THE FORM OF LOCALIZED SHOWERS.
APPROXIMATE POSITIONS OF TROPICAL/EASTERLY WAVES
TYPE SOF 11/12 12/00 12/12 13/00 13/12 14/00 14/12
TW 24N 53W 55W 56W 57W 58W 60W 62W
TW 19N 99W 101W 104W --- --- --- ---
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