557
AXPZ20 KNHC 171557
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED SEP 17 2025
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
03.4S TO 30N, EAST OF 120W INCLUDING THE GULF OF CALIFORNIA, AND
FROM THE EQUATOR TO 30N, BETWEEN 120W AND 140W. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY, WEATHER OBSERVATIONS,
RADAR, AND METEOROLOGICAL ANALYSIS.
BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1500 UTC.
..SPECIAL FEATURES
OFF THE COAST OF SOUTHWESTERN MEXICO (EP96): A BROAD AREA OF 1007
MB LOW PRESSURE LOCATED A FEW HUNDRED NAUTICAL MILES OFF THE
COAST OF SOUTHWESTERN MEXICO NEAR 13N105.5W IS PRODUCING A LARGE
AREA OF SHOWERS AND THUNDERSTORMS AS IS DESCRIBED BELOW.
CURRENTLY, ASSOCIATED WINDS ARE 20-25 KT WITH SEAS OF 8-10 FT.
ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT
OF THIS BROAD SYSTEM, AND A TROPICAL DEPRESSION IS LIKELY TO
FORM IN A COUPLE OF DAYS WHILE IT MOVES WEST-NORTHWESTWARD AT 10
TO 15 KT OVER THE CENTRAL PORTION OF THE EAST PACIFIC. THERE IS
A HIGH CHANCE FOR TROPICAL DEVELOPMENT IN THE NEXT 48 HOURS.
PLEASE READ THE LATEST NHC TROPICAL WEATHER OUTLOOK AT WEBSITE -
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIATWOEP.SHTML FOR MORE DETAILS.
..TROPICAL WAVES
A TROPICAL WAVE AXIS IS NEAR 84W TO THE N OF 06N TO ACROSS
PORTIONS OF WESTERN PANAMA, EASTERN NICARAGUA, AND EASTERN
HONDURAS INTO THE NW CARIBBEAN SEA, MOVING W AT 15-20 KT. NEARBY
CONVECTION IS DISCUSSED IN THE ITCZ/MONSOON TROUGH SECTION
BELOW.
A TROPICAL WAVE AXIS IS NEAR 105.5W, FROM 04N TO 18N NEAR THE SW
COAST OF MEXICO, MOVING SLOWLY W AT AROUND 5 KT. NEARBY
CONVECTION IS DISCUSSED IN THE ITCZ/MONSOON TROUGH SECTION BELOW.
PLEASE SEE THE SPECIAL FEATURES SECTION ABOVE FOR MORE ON THE
HIGH POTENTIAL OF TROPICAL CYCLONE FORMATION WITH THIS TROPICAL
WAVE AND ASSOCIATED LOW PRESSURE, INVEST EP96, ALONG IT.
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
THE MONSOON TROUGH EXTENDS FROM 09N77.5W TO LOW PRESSURE, INVEST
EP96, NEAR 13N105.5W TO 10N140W. SCATTERED TO NUMEROUS MODERATE
AND ISOLATED STRONG CONVECTION IS NOTED WITHIN 360 NM SW OF THE
MONSOON TROUGH BETWEEN 77W AND 100W, AND WITHIN 240 NM N OF THE
MONSOON TROUGH BETWEEN 86W AND 103W. SIMILAR CONVECTION IS NOTED
FROM 09N TO 18N BETWEEN 103W AND 115W. SCATTERED MODERATE
CONVECTION IS NOTED FROM 10N TO 12N BETWEEN 116W AND 120.5W.
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR INFORMATION
ON AN AREA BEING MONITORED FOR TROPICAL FORMATION, INVEST EP96.
FRESH TO STRONG GAP WINDS, AND SEAS OF 7-8 FT, ARE FUNNELING
ACROSS THE GULF OF TEHUANTEPEC. THE 1009 MB REMNANT LOW OF MARIO
IS CENTERED NEAR 24.5N119W. MODERATE TO FRESH WINDS, AND SEAS TO
7 FT, ARE POSSIBLE IN THE VICINITY OF THE REMNANT LOW. MODERATE
TO FRESH WINDS, LOCALLY STRONG, ASSOCIATED WITH EP96 ARE OFF THE
COAST OF SW MEXICO, WHERE SEAS ARE IN THE 7-10 FT RANGE. AN AREA
OF FRESH NE WINDS IS NOTED OFF BAJA CALIFORNIA NORTE DUE SOMEWHAT
TO THE FLOW AROUND AND ASSOCIATED WITH THE REMNANTS OF MARIO.
OTHERWISE, GENTLE TO MODERATE WINDS DOMINATE THE OPEN WATERS OFF
MEXICO. LIGHT TO GENTLE WINDS ARE OVER THE GULF OF CALIFORNIA.
SEAS ARE IN THE 4-6 FT RANGE OFF THE BAJA CALIFORNIA PENINSULA,
AND 6-* FT OVER THE REMAINDER OF OPEN WATERS OFF MEXICO. SEAS
ARE IN THE 1-3 FT RANGE OVER THE GULF OF CALIFORNIA, REACHING 5
FT AT THE ENTRANCE OF THE GULF.
FOR THE FORECAST, FRESH TO LOCALLY STRONG WINDS WILL PULSE IN
THE GULF OF TEHUANTEPEC THROUGH EARLY THU, WITH MODERATE TO
LOCALLY FRESH WINDS PULSING AFTERWARDS. INCREASING WINDS AND SEAS
ARE POSSIBLE WITH THE AREA OF LOW PRESSURE, EP96, BEING
MONITORED WITH A HIGH CHANCE OF TROPICAL CYCLONE FORMATION. AN
AREA OF FRESH TO LOCALLY STRONG WINDS OFF BAJA CALIFORNIA NORTE
WILL DIMINISH TONIGHT. WINDS WILL BE MODERATE OR WEAKER
ELSEWHERE WITH MODERATE TO LOCALLY ROUGH SEAS, EXCEPT SLIGHT SEAS
IN THE GULF OF CALIFORNIA.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
WINDS ARE MAINLY LIGHT TO GENTLE N OF THE MONSOON TROUGH, AND
MODERATE S OF THE MONSOON TOUGH. SEAS ARE IN THE 5-8 FT RANGE IN
S TO SW SWELL ACROSS THE DISCUSSION WATERS. ACTIVE CONVECTION IS
ACROSS MUCH OF THE OFFSHORE WATERS AS DESCRIBED ABOVE WITH
LOCALLY HIGHER WINDS AND SEAS POSSIBLE.
FOR THE FORECAST, ROUGH SEAS OVER THE REGIONAL WATERS WILL
GRADUALLY SUBSIDE THROUGH EARLY THU. MODERATE TO LOCALLY FRESH S
TO SW WINDS ARE EXPECTED S OF THE MONSOON TROUGH THROUGH EARLY
THU, WITH MODERATE OR WEAKER WINDS ELSEWHERE AND OTHERWISE,
EXCEPT LOCALLY FRESH NEAR THE AZUERO PENINSULA AND GULF OF PANAMA
THU.
..REMAINDER OF THE AREA
PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR INFORMATION
ON AN AREA BEING MONITORED FOR TROPICAL FORMATION, INVEST EP96.
THE 1009 MB REMNANT LOW OF MARIO IS CENTERED NEAR 24.5N119W.
MODERATE TO FRESH WINDS AND SEAS TO 7 FT ARE POSSIBLE IN THE
VICINITY OF THE REMNANT LOW. OUTSIDE OF CONDITIONS ASSOCIATED
WITH THE REMNANTS OF MARIO AND EP96, GENTLE TO MODERATE WINDS,
AND SEAS OF 4-7 FT PREVAIL N OF THE MONSOON TROUGH. MODERATE TO
FRESH WINDS PREVAIL S OF THE MONSOON TROUGH. SEAS S OF THE
MONSOON TROUGH ARE IN THE 5-8 FT RANGE W OF 120W, AND 6-10 FT
RANGE E OF 120W IN S TO SW SWELL. A WEAK COLD FRONT IS AT
30N140W.
FOR THE FORECAST, THE REMNANTS OF MARIO WILL MOVE NW AND
DISSIPATE BY THU EVENING. MAINLY MODERATE WINDS WILL PREVAIL S OF
THE MONSOON TROUGH, EXCEPT LOCALLY FRESH IN THE CENTRAL WATERS
NEAR THE AXIS THROUGH THE END OF THE WEEK. ROUGH SEAS IN THE
CENTRAL WATERS S OF THE MONSOON TROUGH WILL PERSIST THROUGH
THIS EVENING, THEN WILL CONSOLIDATE AROUND EP96, WHICH HAS A
HIGH CHANCE OF TROPICAL CYCLONE FORMATION. REGARDLESS OF
DEVELOPMENT OF EP96, EXPECT INCREASING WINDS AND BUILDING SEAS IN
ITS VICINITY. A WEAK COLD FRONT WILL MOVE THROUGH THE NORTHERN
WATERS STARTING LATER TODAY, LEADING TO FRESHENING NE WINDS AND
BUILDING SEAS WEST OF THE BOUNDARY AS IT SLOWLY STALLS INTO THE
UPCOMING WEEKEND. MARINE CONDITIONS MAY IMPROVE AND BE QUITE
TRANQUIL ACROSS THE OPEN WATERS BY THE END OF THE WEEKEND AND
INTO EARLY NEXT WEEK.
LEWITSKY
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page