838
FXCA20 KWBC 061904
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
304 PM EDT TUE OCT 06 2026
FORECAST BULLETIN 06 OCTOBER 2026 AT 1900 UTC:
ACROSS THE CARIBBEAN...
A TROPICAL WAVE IS CURRENTLY MOVING ACROSS THE LESSER ANTILLES AND
IS EXPECTED TO MAINTAIN ITS ORGANIZATION AS IT CONTINUES MOVING
WEST ACROSS THE CARIBBEAN SEA. MEANWHILE IN THE UPPER LEVELS,
EXPECT THE PRESENCE OF AN TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) ACROSS THE WEST CARIBBEAN. AS THE TROPICAL WAVE APPROACHES
THE TUTT ON WEDNESDAY, EXPECT A SUBTLE INCREASE IN PRECIPITABLE
WATER ACROSS THE REGION AND IN ITS PROPAGATION SPEED.
ADDITIONALLY, THE MID-LEVEL MOISTURE WILL INCREASE BEHIND THE
TROUGH AXIS. THIS WAVE AXIS IS EXPECTED TO ARRIVE INTO THE SOUTH
DOMINICAN REPUBLIC ON WEDNESDAY AFTERNOON/EVENING AND RAIN CHANCES
WILL INCREASE SUBSEQUENTLY. THE TROPICAL WAVE WILL BE EXITING
HAITI ON THURSDAY MORNING AND IS EXPECTED TO MOVE INTO JAMAICA AND
SOUTHEAST CUBA. DAILY TOTAL PRECIPITATION MAXIMA OF 15 - 25MM IN
THE VICINITY OF THE TROPICAL WAVE FOR THE NEXT THREE DAYS.
OROGRAPHIC ENHANCEMENT AND LOCAL EFFECTS WILL ALSO FAVOR ISOLATED
HIGHER ACCUMULATIONS.
ACROSS TROPICAL SOUTH AMERICA...
A PERSISTENT SURFACE TO LOW LEVEL TROUGH WILL BE DEVELOPING ALONG
THE COAST OF ECUADOR WHILE WESTERLY LOW LEVEL WINDS WILL BE
DOMINANT ALONG THE COAST OF COLOMBIA FOR THE NEXT THREE DAYS.
OVERALL, THE ENVIRONMENT WILL REMAIN VERY MOIST AND UNSTABLE. THE
MAIN DRIVING FORCE FOR CONVECTIVE AND SHOWER INITIATION WILL BE
LOCAL EFFECTS AND OROGRAPHIC ENHANCEMENT. MODERATE TOTAL
PRECIPITATION MAXIMA ARE LIKELY IN THIS REGION THROUGH THE
FORECAST PERIOD. ALSO ALONG NORTH COLOMBIA AND VENEZUELA,
ANTICIPATE THE DEVELOPMENT OF ISOLATED THUNDERSTORMS AS THE
AFOREMENTIONED TROPICAL WAVE MOVES ACROSS THE CARIBBEAN SEA FOR
WEDNESDAY AND THURSDAY.
EAST OF THE ANDES, EXPECT CONTINUOUS EASTERLY MID-LEVEL WINDS INTO
THE FOOTHILLS THAT WILL FAVOR MOISTURE POOLING ACROSS THE WEST
AMAZON BASIN. REGIONS OF LOCALIZED LOW LEVEL WIND CONVERGENCE ARE
EXPECTED TO DEVELOP NEAR CABECA DO CACHORRO. EXPECT THE
DEVELOPMENT OF CONVECTION IN THIS AREA. ELSEWHERE IN THE REGION,
LOCAL EFFECTS AND OROGRAPHIC ENHANCEMENT WILL SUPPORT DIURNAL
CONVECTION AND SHOWERS ACROSS THE REST OF THE NORTHWEST AND
SOUTHWEST AMAZON.
ACROSS CENTRAL AMERICA...
THE AFOREMENTIONED TUTT WILL CONTINUE TO RESIDE OVER CENTRAL
AMERICA THROUGH THURSDAY, HELPING DESTABILIZE THE ENVIRONMENT AND
PROVIDING UPPER LEVEL VENTILATION ACROSS ITS BASE. ITS BASE WILL
BE SITUATED OVER PANAMA AND COSTA RICA. THE TUTTS STRUCTURE WILL
WEAKEN AFTER FRIDAY MORNING. SIMULTANEOUSLY, THE SURFACE-TO-925
HPA MONSOON TROUGH WILL BE ACROSS THE REGION, HELPING REINFORCE
ONSHORE FLOW ACROSS THE NICARAGUA AND COSTA RICAN CARIBBEAN COAST
AND THE ATLANTIC COAST OF SOUTH COSTA RICA AND PANAMA. NOTE THAT
WITH THE ARRIVAL OF THE AFOREMENTIONED TROPICAL WAVE INTO THE
REGION, A BROAD CYCLONIC CIRCULATION IN THE 850 HPA WIND FLOW WILL
DEVELOP AS WELL. CONVECTION IS EXPECTED TO DEVELOP DAILY ACROSS
THE REGION, WITH THE GREATEST PRECIPITATION ACCUMULATIONS
OCCURRING SOUTH OF THE CENTRAL CARIBBEAN COAST OF NICARAGUA.
ACROSS MEXICO...
TWO AREAS OF LOW PRESSURE WILL BE INFLUENCING THE PRECIPITATION
REGIME ACROSS MEXICO FOR THE REST OF THE WEEK. THE FIRST LOW
PRESSURE SYSTEM IS CURRENTLY LOCATED OFF THE COAST OF SOUTHWEST
MEXICO. STARTING ON WEDNESDAY, THIS SYSTEM WILL SUPPORT THE
TRANSPORT OF MOIST TROPICAL AIR INTO THE INTERIOR OF MEXICO,
SPECIFICALLY SOUTH-CENTRAL MEXICO. ADDITIONALLY, THERE WILL BE
MID-LEVEL SHORTWAVE PERTURBATIONS THAT WILL REINFORCE ASCENT IN
THE REGION PARTICULARLY FOR THURSDAY AND THUS LEADING TO AN
INCREASE IN PRECIPITATION MAXIMA ALONG THE COASTS. ON FRIDAY, THE
LOW PRESSURE SYSTEM WILL CONTINUE MOVING PARALLEL TO THE
SOUTHWEST/WEST COASTLINE OF MEXICO AND CONTINUE TO SUPPORT
MOISTURE CONVERGENCE ALONG THE COAST. ELEVATED TOTAL PRECIPITATION
MAXIMA ARE LIKELY FOR THURSDAY AND FRIDAY WITH THE AFOREMENTIONED
CONDITIONS.
THE SECOND LOW PRESSURE SYSTEM IS CURRENTLY RESIDING IN THE BAY OF
CAMPECHE AND IS EXPECTED TO MOVE PARALLEL TO THE WESTERN YUCATAN
PENINSULA BEFORE MOVING INTO THE NORTHEAST GULF. THIS SYSTEM WILL
HELP INDUCE SHOWERS ACROSS THE CAMPECHE AND WEST YUCATAN COAST
STARTING WEDNESDAY AND CONTINUING INTO THE DAY ON FRIDAY. ELEVATED
TOTAL PRECIPITATION MAXIMA IS LIKELY WITH THIS EVENT.
OTHER REGIONS BEING INDIRECTLY AFFECTED BY THE PRESENCE OF THESE
SYSTEMS IS CENTRAL MEXICO. THE INCREASE IN MOISTURE INTO THE
REGION WILL LEAD TO THE DEVELOPMENT OF DIURNAL SHOWERS AND
THUNDERSTORMS. THESE PRECIPITATION FEATURES WILL BE AIDED BY
OROGRAPHIC ENHANCEMENT AND DIURNAL/LOCAL EFFECTS. LASTLY, ACROSS
COAHUILA, EXPECT THE ARRIVAL OF A MID-LEVEL SHORTWAVE TROUGH FOR
THURSDAY THAT WILL HELP DEVELOP CONVECTION IN THE REGION AND
INCREASE THE RISK FOR SEVERE WEATHER. AS THE AFOREMENTIONED LOW
PRESSURE SYSTEM IN THE GULF SWINGS NORTHEASTWARD, THERE WILL BE
MOISTURE PLUMES CONVERGING INTO NORTHEAST MEXICO AND ALONG THE
GULF COAST THAT WILL ALSO SUPPORT THE SUSTENANCE OF PRECIPITATION
FOR THURSDAY.
TROPICAL WAVES INITIALIZED AT 12 UTC:
TYPE SOF INIT 07/00 07/12 08/00 08/12 09/00 09/12 10/00 10/12
TW 19N 64W 66W 69W 72W 75W 77W 79W 81W 83W
TW 17N 85W 87W 89W DISS --- --- --- --- ---
TINOCO-MORALES...(WPC)
ALAMO...(WPC)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page