159
AXPZ20 KNHC 220917
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED OCT 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.
..TROPICAL WAVES
A TROPICAL WAVE IS OVER CENTRAL AMERICA. ITS AXIS IS ALONG
84W/85W SOUTH OF 16N, MOVING WEST AT 10 TO 15 KT. SCATTERED
SHOWERS AND THUNDERSTORMS ARE NOTED OVER THE SW CARIBBEAN, AND
THE COASTAL PLAINS OF NICARAGUA IN THE WAKE OF THE WAVE AXIS. .
A TROPICAL WAVE, WITH AXIS ALONG 105W, LOCATED SEVERAL HUNDRED
MILES SOUTH-SOUTHWEST OF THE COAST OF SOUTHWESTERN MEXICO IS
PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS. ENVIRONMENTAL
CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS
SYSTEM, AND A TROPICAL DEPRESSION IS LIKELY TO FORM LATE THIS
WEEK OR OVER THE WEEKEND WHILE IT MOVES GENERALLY WESTWARD AT 10
TO 15 KT. CURRENTLY THIS SYSTEM HAS A LOW CHANCE OF TROPICAL
CYCLONE FORMATION THROUGH 48 HOURS, AND A HIGH CHANCE THROUGH 7
DAYS. PLEASE, REFER TO THE LATEST NHC TROPICAL WEATHER OUTLOOK AT
WWW.HURRICANES.GOV FOR MORE DETAILS.
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH
THE MONSOON TROUGH EXTENDS FROM 07N73W TO 12N97W TO 1011 MB LOW
PRES LOCATED NEAR 12.5N114W TO 08N125W. THE ITCZ CONTINUES FROM
08N125W TO 09N125W TO 10N130W, THEN RESUMES FROM 11N135W TO BEYOND
10N140W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS
FROM 14N TO 16N BETWEEN 92W AND 94.5W. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS SEEN FROM 09N TO 15N BETWEEN 103W
AND 117W. ANOTHER CLUSTER OF MODERATE TO STRONG CONVECTION IS
WITHIN ABOUT 90 NM N SEMICIRCLE OF THE LOW PRESSURE LOCATED NEAR
12N132W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 07N TO
12N BETWEEN 134W AND 138W.
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
A WEAK RIDGE CONTINUES ACROSS THE OFFSHORE FORECAST WATERS OF
BAJA CALIFORNIA, CENTERED ON 1017 MB HIGH PRESSURE LOCATED NEAR
26N121W. RECENT SATELLITE DERIVED WIND DATA INDICATE THAT THIS
PATTERN SUPPORTS GENTLE TO MODERATE NW TO N WINDS ACROSS THE BAJA
CALIFORNIA WATERS. SIMILAR WIND SPEEDS AREA NOTED ACROSS THE
GULF OF CALIFORNIA. SEAS ARE 5 TO 7 FT IN NW SWELL ACROSS THE
OUTER WATER OF BAJA CALIFORNIA, AND 1 TO 3 FT ACROSS THE GULF
WATERS. GENTLE TO MODERATE NW WINDS AND MODERATE SEAS ALSO
DOMINATE THE OFFSHORE WATERS OF JALISCO AND COLIMA WHILE LIGHT TO
GENTLE WINDS AND MODERATE SEAS IN MIXED NW AND SW SWELL ARE
OBSERVED ACROSS THE REMAINDER OF THE MEXICAN OFFSHORE WATERS
EXCEPT IN THE TEHUANTEPEC REGION WHERE FRESH TO STRONG N TO NE
GAP WINDS ARE BLOWING. SEAS ARE 6 TO 7 FT WITHIN THESE WINDS.
FOR THE FORECAST, A RIDGE ACROSS THE EASTERN SLOPES OF THE SIERRA
MADRE MOUNTAINS IN MEXICO WILL CONTINUE TO SUPPORT A GAP WIND
EVENT ACROSS THE TEHUANTEPEC REGION THROUGH FRI MORNING. FRESH
TO STRONG NORTHERLY WINDS, REACHING NEAR 30 KT, AND MODERATE TO
ROUGH SEAS TO NEAR 7 OR 8 FT, ARE EXPECTED WITH THIS EVENT DURING
THE OVERNIGHT AND EARLY MORNING HOURS THE REMAINDER OF THE WORK-
WEEK. ADDITIONAL PULSES OF NW SWELL WILL CONTINUE TO PROPAGATE
ACROSS THE OFFSHORE WATERS OF BAJA CALIFORNIA THROUGH THE
FORECAST PERIOD, SUPPORTING MODERATE TO ROUGH SEAS, AND ARE
EXPECTED TO PEAK WED THROUGH THU. WINDS WILL FRESHEN ACROSS THE
NEAR AND OFFSHORE WATERS OF BAJA CALIFORNIA TODAY, AND CONTINUE
THROUGH THU EVENING AS THE PRESSURE GRADIENT TIGHTENS SOME ACROSS
THE AREA BETWEEN THE HIGH PRESSURE TO THE WEST AND LOWER PRESSURES
OVER NORTH-CENTRAL MEXICO. LOOKING AHEAD, A TROPICAL WAVE LOCATED
SEVERAL HUNDRED MILES SOUTH-SOUTHWEST OF THE COAST OF SOUTHWESTERN
MEXICO HAS THE POTENTIAL FOR TROPICAL CYCLONE FORMATION. PLEASE,
SEE THE TROPICAL WAVES SECTION ABOVE FOR MORE DETAILS.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
RECENT SCATTEROMETER DATA SHOW MODERATE TO FRESH NE TO E WINDS
ACROSS THE PAPAGAYO REGION AND DOWNWIND TO NEAR 89W WITH SEAS TO
6 FT. ELSEWHERE, LIGHT TO GENTLE WINDS ARE N OF THE MONSOON
TROUGH WITH GENTLE TO MODERATE SW TO W WINDS TO THE S OF IT. SEAS
ARE IN GENERAL 4 TO 5 FT, PRIMARILY IN SW SWELL, EXCEPT IN THE
LEE OF THE GALAPAGOS ISLANDS WHERE SLIGHT SEAS PREVAIL. SCATTERED
SHOWERS WITH EMBEDDED THUNDERSTORMS ARE IN THE VICINITY OF THE
MONSOON TROUGH.
FOR THE FORECAST, MODERATE TO FRESH NE GAP WINDS ACROSS THE
PAPAGAYO REGION WILL DIMINISH TODAY, AND BECOME VARIABLE THROUGH
THE END OF THE WEEK. LITTLE CHANGE IN THE WEATHER PATTERN IS
FORECAST ELSEWHERE, WITH MODERATE S TO SW WINDS AND MODERATE SEAS
EXPECTED SOUTH OF THE MONSOON TROUGH THROUGH THE FORECAST PERIOD.
..REMAINDER OF THE AREA
A WEAK RIDGE COVERS THE FORECAST WATERS N OF 15N AND W OF 115W.
UNDER THE INFLUENCE OF THIS SYSTEM, MAINLY LIGHT TO GENTLE WINDS
ARE NOTED N OF 20N WHILE GENTLE TO MODERATE WINDS ARE BETWEEN THE
ITCZ/MONSOON TROUGH AND 20N WITH THE EXCEPTION OF FRESH TO STRONG
WINDS WITHIN 120 NM ACROSS THE N SEMICIRCLE AND 90 NM ACROSS THE
SE QUADRANT OF A 1010 MB LOW PRESSURE LOCATED ALONG THE MONSOON
TROUGH NEAR 12N132W. MODERATE TO ROUGH SEAS IN NW SWELL DOMINATE
MOST OF THE AREA.
FOR THE FORECAST, STRONG HIGH PRESSURE NORTH OF THE HAWAIIAN
ISLANDS WILL BUILD EASTWARD, TO THE SOUTH OF A FRONTAL SYSTEM,
AND INTO THE NORTHERN WATERS THROUGH FRI, AND REINFORCE THE
CURRENT RIDGE DOMINATING THE FORECAST AREA. THE PRESSURE GRADIENT
BETWEEN THE RIDGE AND A WESTWARD MOVING LOW PRESSURE CENTER
ALONG THE MONSOON TROUGH NEAR 132W WILL SUPPORT FRESH TO STRONG
WINDS AND ROUGH SEAS NEAR THE LOW CENTER THROUGH AT LEAST THU
MORNING. THE LOW IS FORECAST TO CROSS 140W BY THU AFTERNOON WHILE
IT OPENS UP INTO A TROUGH. A NEW SET OF LONG PERIOD NW SWELL WILL
REACH THE NW CORNER OF THE FORECAST REGION ON THU BRINGING ANOTHER
ROUND OF ROUGH SEAS.
GR
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