355
AXPZ20 KNHC 210919
TWDEP
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE OCT 21 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, WITH AXIS ALONG 99W, LOCATED A FEW HUNDRED MILES
SOUTH OF THE COAST OF SOUTHERN 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 AS IT MOVES GENERALLY WESTWARD
AT 10 TO 15 KT, REMAINING WELL OFFSHORE OF MEXICO. 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 A 1010 MB LOW PRESSURE LOCATED
OVER NORTHERN COLOMBIA NEAR 10N74W TO 07N80W TO 13N105W TO A
1011 LOW PRESSURE SITUATED NEAR 12N113W TO 10N122W. THE ITCZ
EXTENDS FROM 10N130W TO BEYOND 09N140W. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION CAN BE FOUND FROM 02N TO 07N E OF 79W
TO THE COAST OF COLOMBIA, FROM 09N TO 13.5N BETWEEN 86W AND 91W,
AND FROM 10N TO 12N BETWEEN 99W AND 104W. SCATTERED MODERATE
CONVECTION IS FROM 09N TO 12N BETWEEN 126W AND 129W.
..OFFSHORE WATERS WITHIN 250 NM OF MEXICO
A RIDGE DOMINATES THE OFFSHORE FORECAST WATERS OF BAJA CALIFORNIA,
CENTERED ON 1017 MB HIGH PRESSURE LOCATED NEAR 26N121W. RECENT
SATELLITE SCATTEROMETER DATA SHOW THAT THIS PATTERN SUPPORTS
GENTLE TO MODERATE NW TO N WINDS ACROSS THE BAJA CALIFORNIA
WATERS. SEAS THERE ARE 5 TO 7 FT IN NW SWELL. SIMILAR WIND SPEEDS
ARE ALSO FOUND THROUGHOUT THE GULF OF CALIFORNIA. ELSEWHERE
ACROSS THE MEXICAN OFFSHORE WATERS FROM CABO CORRIENTES TO PUERTO
ANGEL, LIGHT AND VARIABLE WINDS AND MODERATE SEAS TO 5 FT PREVAIL.
FRESH TO STRONG N TO NE GAP WINDS ARE BLOWING ACROSS THE GULF OF
TEHUANTEPEC AND DOWNWIND TO ABOUT 15N. SEAS ARE 6 TO 7 FT WITHIN
THESE WINDS.
FOR THE FORECAST, BUILDING HIGH PRESSURE ACROSS THE EASTERN SLOPES
OF THE SIERRA MADRE MOUNTAINS IN MEXICO WILL COMBINE WITH BROAD
LOW PRESSURE ACROSS THE SW CARIBBEAN TO SUPPORT AN EARLY SEASON
GAP WIND EVENT ACROSS THE TEHUANTEPEC REGION THROUGH THU NIGHT.
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 MOST OF THE WEEK. LONG PERIOD
NW SWELL WILL PROPAGATE ACROSS THE OFFSHORE WATERS OF BAJA CALIFORNIA
THROUGH THE FORECAST PERIOD, SUPPORTING MODERATE TO ROUGH SEAS.
WINDS WILL FRESHEN IN THE OFFSHORE WATERS OF BAJA CALIFORNIA BY
WED MORNING, AND CONTINUE THROUGH THU EVENING AS THE PRESSURE
GRADIENT TIGHTENS SOME ACROSS THE AREA BETWEEN THE HIGH PRESSURE
RIDGE TO THE WEST AND LOWER PRESSURES OVER NORTH-CENTRAL MEXICO.
LOOKING AHEAD, A TROPICAL WAVE LOCATED A FEW HUNDRED MILES SOUTH
OF THE COAST OF SOUTHERN MEXICO HAS THE POTENTIAL FOR TROPICAL
CYCLONE FORMATION. PLEASE, SEE THE TROPICAL WAVES SECTION FOR
MORE DETAILS.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS AFFECTING
THE OFFSHORE WATERS OF NORTHERN CENTRAL AMERICA, ROUGHLY FROM
NORTHERN COSTA RICA TO SE GUATEMALA. STRONG WINDS ARE NOTED
WITHIN THIS CONVECTIVE ACTIVITY. SCATTERED MODERATE CONVECTION
IS NEAR THE COAST OF COLOMBIA. RECENT SCATTEROMETER DATA INDICATE
GENTLE TO MODERATE SW WINDS SOUTH OF THE MONSOON TROUGH, AND
LIGHT TO GENTLE WINDS TO THE NORTH OF IT. SEAS IN THESE WATERS
ARE MODERATE IN MIXED S AND SW SWELL, EXCEPT IN THE LEE OF THE
GALAPAGOS ISLANDS.
FOR THE FORECAST, FRESH NE GAP WINDS ARE EXPECTED ACROSS THE
PAPAGAYO REGION TODAY, INCREASING TO STRONG SPEEDS BY THIS
EVENING, THEN GRADUALLY DIMINISH ON WED. LITTLE CHANGE IN THE
WEATHER PATTERN IS FORECAST ELSEWHERE. MODERATE S TO SW WINDS
AND MODERATE SEAS ARE EXPECTED SOUTH OF THE MONSOON TROUGH
THROUGH THE FORECAST PERIOD.
..REMAINDER OF THE AREA
A 1028 MB HIGH PRESSURE IS LOCATED N OF AREA NEAR 40N138W. IT
EXTENDS A BROAD RIDGE TO THE SOUTH AND SOUTHEAST, AND COVERS THE
FORECAST WATERS N OF 15N AND W OF 113W. FRESH TO STRONG WINDS ARE
NOTED WITHIN 120 NM N SEMICIRCLE AND 90 SE QUADRANT OF A LOW
PRESSURE LOCATED ALONG THE MONSOON TROUGH NEAR 11N127W. SEAS
THERE ARE 7 TO 9 FT. MODERATE TO LOCALLY FRESH WINDS ARE FOUND
ELSEWHERE FROM 10N TO 19N AND W OF 125W. MODERATE SEAS OF 5 TO 7
FT ARE WITHIN THESE WINDS. MODERATE TO LOCALLY FRESH NE TO E
WINDS AND ROUGH SEAS IN NW SWELL DOMINATE THE NW CORNER OF THE
FORECAST REGION, PARTICULARLY N OF 28N W OF 125W. MODERATE TO
LOCALLY FRESH SOUTHERLY WINDS AND MODERATE SEAS ARE FOUND SOUTH
OF THE MONSOON TROUGH W OF 110W. ELSEWHERE, MODERATE OR WEAKER
WINDS AND MODERATE SEAS ARE PREVALENT.
FOR THE FORECAST, THE RIDGE WILL REMAIN IN CONTROL OF THE WEATHER
PATTERN ACROSS THE N WATERS, PARTICULARLY N OF 10N AND W OF 120W
THIS WEEK PRODUCING A GENTLE TO MODERATE ANTICYCLONIC FLOW. THE
PRESSURE GRADIENT BETWEEN THE RIDGE AND A WESTWARD-MOVING LOW
PRESSURE CENTER ALONG THE MONSOON TROUGH NEAR 127W WILL SUPPORT
FRESH TO STRONG WINDS AND ROUGH SEAS NEAR THE LOW CENTER THROUGH
AT LEAST THE MIDDLE PORTION OF THIS WEEK. THE LOW IS FORECAST TO
CROSS 140W ON THU WHILE IT OPENS UP INTO A TROUGH.
GR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page