643
FXCA20 KWBC 251914
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
314 PM EDT THU SEP 25 2025
FORECAST BULLETIN 25 SEPTEMBER 2025 AT 1900 UTC:
THE BAHAMAS AND CARIBBEAN:
A TROPICAL WAVE (AL94), CURRENTLY LOCATED AROUND 70W, CONTINUES TO
GENERATE WIDESPREAD PRECIPITATION OVER THE CARIBBEAN AS IT
CONTINUES ITS WEST-NORTHWESTWARD MOVEMENT. OVER PUERTO RICO,
MOISTURE ADVECTION WILL CONTINUE TO FAVOR SHOWERS AND
THUNDERSTORMS MAINLY OVER THE SOUTHWESTERN COAST TODAY AND FRIDAY.
CONVECTIVE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE IS ALREADY
AFFECTING HISPANIOLA TODAY. THIS CONVECTIVE ACTIVITY IN
COMBINATION WITH ENHANCEMENT BY OROGRAPHIC LIFTING IS EXPECTED TO
CAUSE HEAVY RAINFALL OVER HISPANIOLA THROUGH TODAY AND FRIDAY. THE
MOST SIGNIFICANT IMPACTS ARE EXPECTED OVER EAST AND SOUTH
DOMINICAN REPUBLIC, WITH ACCUMULATIONS REACHING 100-200MM.
MOISTURE ADVECTION FROM THE SOUTH COMBINED WITH UPPER LEVEL
DYNAMICS WILL SUSTAIN PRECIPITATION ACROSS HISPANIOLA FROM FRIDAY
INTO SATURDAY.
THE WAVE IS FORECAST TO DEVELOP INTO A CLOSED LOW AFTER CROSSING
HISPANIOLA, AND IS FORECAST TO APPROACH THE TURKS AND CAICOS AS
WELL AS THE SOUTHEAST BAHAMAS. ACCORDING TO THE LATEST NATIONAL
HURRICANE CENTER ADVISORY, THE SYSTEM HAS A 70% CHANCE OF
DEVELOPING INTO A TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS.
REGARDLESS OF DEVELOPMENT, HEAVY RAINFALL AND THUNDERSTORMS ARE
EXPECTED TO AFFECT THE TURKS AND CAICOS WITH ACCUMULATIONS AROUND
75-150MM AND SOUTHERN BAHAMAS FROM 100-200MM FROM FRIDAY TO
SATURDAY. AS THE SYSTEM TRACKS NORTHWESTWARD PRECIPITATION WILL
CONTINUE OVER MOST OF THE BAHAMAS WITH ACCUMULATIONS AROUND
50-100MM FOR CENTRAL BAHAMAS. AN INCREASE IN PRECIPITABLE WATER
AND ENHANCED LOW-LEVEL MOISTURE CONVERGENCE WILL ALSO BRING
RAINFALL TO EASTERN CUBA FROM FRIDAY TO SATURDAY.
MEXICO AND CENTRAL AMERICA:
REMNANT MOISTURE FROM HURRICANE NARDA CONTINUES TO LINGER ALONG
THE WESTERN PACIFIC COAST OF MEXICO. ENHANCED MOISTURE OVER THE
BAJA CALIFORNIA, THE PRESENCE OF A LOW- TO MID- LEVEL TROUGH,
ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE AND UPPER-LEVEL
DIVERGENCE IN THE PERIPHERY OF AN UPPER-LEVEL HIGH WILL ENHANCE
PRECIPITATION ALONG THE SIERRA MADRE OCCIDENTAL FOR THE NEXT TWO
DAYS. AS AN UPPER-LEVEL TROUGH MOVES OVER THE BAJA CALIFORNIA
PENINSULA ON SATURDAY AND THE UPPER-LEVEL HIGH MOVES INTO CENTRAL
MEXICO, DIVERGENCE AND INSTABILITY WILL BE ENHANCED FURTHER SOUTH.
IN SOUTHWESTERN MEXICO A DISSIPATING TROPICAL WAVE IS BRINGING
SOME MOISTURE IN THE REGION, WITH LOW-LEVEL WINDS PERPENDICULAR TO
THE COAST TODAY THROUGH FRIDAY.
MOSTLY DRY CONDITIONS WILL PERSIST FOR YUCATAN AND PARTS OF
CENTRAL AMERICA, INCLUDING NICARAGUA, HONDURAS AND GUATEMALA, AS
DRY STABLE AIR PREVAILS IN THE REGION THROUGH SATURDAY, ALTHOUGH
LOCALIZED BUT BRIEF PRECIPITATION SHOULD BE EXPECTED. MORE
SEASONABLE PRECIPITATION IS LIKELY TO OCCUR FROM SATURDAY TO
SUNDAY, AS DEEPER MOISTURE ENTERS THE REGION. OVER COSTA RICA AND
PANAMA, MOST OF THE PRECIPITATION WILL BE DUE TO THE PRESENCE OF
THE MONSOON TROUGH IN THE AREA AND LOW-LEVEL CIRCULATION THAT WILL
FAVOR MOIST ONSHORE FLOW FOR THE NEXT THREE DAYS. FROM TODAY INTO
SATURDAY A MID-LEVEL TROUGH WILL ENHANCE INSTABILITY OVER COSTA
RICA AND PANAMA, WHICH WILL COMBINE WITH THE UPPER-LEVEL
DIVERGENCE LEADING TO RAINFALL ACCUMULATIONS AROUND 20-45MM EACH
DAY, WITH LOCALIZED HIGHER VALUES.
SOUTH AMERICA:
MOST PRECIPITATION ACROSS TROPICAL SOUTH AMERICA FOR THE NEXT
THREE DAYS WILL HAPPEN OVER THE NORTHWESTERN PORTION OF THE
REGION. IN THE WEST COAST OF COLOMBIA, MOIST FLOW COMING FROM THE
EASTERN PACIFIC WILL ENHANCE LOW LEVEL MOISTURE CONVERGENCE INTO
THE REGION. FURTHER NORTH, THE PANAMANIAN LOW, MOISTURE ADVECTION
AND THE PRESENCE OF A MID-LEVEL TROUGH WILL ENHANCE CONVECTIVE
ACTIVITY PARTICULARLY ON FRIDAY AND SATURDAY OVER WESTERN
COLOMBIA. OVER THE WESTERN AMAZON BASIN THE PRESENCE OF LOW-LEVEL
INDUCED TROUGHS WILL BRING THUNDERSTORMS TO THE AREA TODAY INTO
FRIDAY.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 26/00 26/12 27/00 27/12 28/00 28/12 29/00
TW 21N 70W 71W 72W LOW --- --- --- ---
TW 16N 101W 103W 105W 107W 109W --- --- ---
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