Mazatlan to Banderas Bay Forecast
August 23, 2026, 8:00 pm (UTC: -05:00)
Subject: Mazatlan to Banderas Bay Forecast
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This forecast has not been reviewed. It was generated from an automatic model.
.WARNINGS.
...HURRICANE WARNING...
.TROPICAL STORM ISELLE NEAR 16.9N 115.1W 1001 MB AT 2100 UTC AUG 23
MOVING NW OR 315 DEG AT 14 KT. MAXIMUM SUSTAINED WINDS 45 KT GUSTS
55 KT. TROPICAL STORM FORCE WINDS WITHIN 100 NM E SEMICIRCLE...110
NM SW QUADRANT AND 0 NM NW QUADRANT. SEAS 4 M OR GREATER WITHIN 90
NM E SEMICIRCLE...45 NM SW QUADRANT AND 0 NM NW QUADRANT WITH SEAS
TO 5.0 M. ELSEWHERE WITHIN 180 NM OF CENTER...EXCEPT 120 NM SW
QUADRANT WINDS 20 TO 33 KT. SEAS 3.0 TO 4.0 M. REMAINDER OF THE AREA
FROM 10.5N TO 13N BETWEEN 112W AND 118W S TO SW WINDS 20 TO 30 KT.
SEAS 2.5 TO 3.0 M.
.24 HOUR FORECAST TROPICAL STORM ISELLE NEAR 19.6N 117.8W.
MAXIMUM SUSTAINED WINDS 60 KT GUSTS 75 KT. TROPICAL STORM FORCE
WINDS WITHIN 120 NM NE QUADRANT...130 NM SE QUADRANT...90 NM SW
QUADRANT...AND 60 NM NW QUADRANT. SEAS 4 M OR GREATER WITHIN 180 NM
E SEMICIRCLE...120 NM SW QUADRANT AND 90 NM NW QUADRANT WITH SEAS TO
6.0 M. ELSEWHERE WITHIN 210 NM E SEMICIRCLE AND 150 NM W SEMICIRCLE
OF CENTER WINDS 20 TO 33 KT. SEAS 3.0 TO 4.0 M. REMAINDER OF THE
AREA FROM 12N TO 23N BETWEEN 111W AND 121W WINDS 20 KT OR LESS. SEAS
2.5 TO 3.0 M IN MIXED SWELL.
.36 HOUR FORECAST HURRICANE ISELLE NEAR 20.8N 119.4W. MAXIMUM
SUSTAINED WINDS 65 KT GUSTS 80 KT.
.48 HOUR FORECAST HURRICANE ISELLE NEAR 21.4N 121.1W. MAXIMUM
SUSTAINED WINDS 65 KT GUSTS 80 KT. TROPICAL STORM FORCE WINDS WITHIN
130 NM NE QUADRANT...110 NM SE QUADRANT...60 NM SW QUADRANT...AND 90
NM NW QUADRANT. SEAS 4 M OR GREATER WITHIN 210 NM E SEMICIRCLE...AND
120 NM W SEMICIRCLE OF CENTER WITH SEAS TO 7.0 M. ELSEWHERE WITHIN
240 NM E SEMICIRCLE AND 180 NM W SEMICIRCLE OF CENTER WINDS 20 TO 33
KT. SEAS 3.0 TO 4.0 M. REMAINDER OF THE AREA FROM 14N TO 27N BETWEEN
113W AND 125W WINDS 20 KT OR LESS. SEAS 2.5 TO 3.0 M IN MIXED SWELL.
.GULF OF CALIFORNIA N OF 27N SE TO S WINDS 20 TO 25 KT. SEAS LESS
THAN 2.5 M.
.12 HOUR FORECAST WINDS 20 KT OR LESS. SEAS LESS THAN 2.5 M.
A RIDGE CONTINUES TO DOMINATE THE OFFSHORE FORECAST WATERS OF
BAJA CALIFORNIA NORTE SUPPORTING GENTLE TO MODERATE NW WINDS AND
MODERATE SEAS. STRONG WINDS AND ROUGH SEAS ASSOCIATED WITH THE
OUTER PERIPHERY OF T.S. ISELLE ARE REACHING THE REVILLAGIGEDO
ISLANDS, PARTICULARLY CLARION ISLAND. RECENT SCATTEROMETER DATA
PROVIDE OBSERVATIONS OF FRESH TO STRONG SE TO S WINDS IN THE
GULF OF CALIFORNIA N OF 27N. MODERATE SEAS ARE NOTED WITH THESE
WINDS. FRESH TO STRONG N GAP WINDS PERSIST ACROSS THE GULF OF
TEHUANTEPEC AND DOWNWIND TO ABOUT 14.5N BASED ON RECENT
SCATTEROMETER DATA. SEAS ARE 6 TO 8 FT WITH THESE WINDS.
FOR THE FORECAST, TROPICAL STORM ISELLE WILL MOVE TO 18.2N 116.3W
MON MORNING, 19.6N 117.8W MON AFTERNOON, STRENGTHEN TO A HURRICANE
NEAR 20.8N 119.4W TUE MORNING, 21.4N 121.1W TUE AFTERNOON, WEAKEN
TO A TROPICAL STORM NEAR 21.9N 122.8W WED MORNING, AND 22.4N
124.6W WED AFTERNOON. ISELLE WILL CHANGE LITTLE IN INTENSITY AS
IT MOVES TO NEAR 23.3N 128.4W THU AFTERNOON. A RIDGE WILL PERSIST
BETWEEN BAJA CALIFORNIA AND ISELLE THROUGH ABOUT MIDWEEK SUPPORTING
GENTLE TO MODERATE NW TO N WINDS NORTH OF CABO SAN LAZARO. STRONGER
WINDS AND HIGHER SEAS ARE EXPECTED ACROSS THE FORECAST ZONE BETWEEN
CABO SAN LAZARO AND CABO SAN LUCAS, INCLUDING THE REVILLAGIGEDO
ISLANDS, DUE TO THE PROXIMITY OF ISELLE. THE FORECAST CALLS FOR
STORM CONDITIONS IN THE REVILLAGIGEDO ISLANDS TONIGHT, AND STORM
CONDITIONS POSSIBLE IN THE REVILLAGIGEDO ISLANDS AND THE
FORECAST ZONE BETWEEN CABO SAN LAZARO AND CABO SAN LUCAS ON MON.
THE FRESH TO LOCALLY STRONG WINDS OVER THE NORTH AND CENTRAL
PARTS OF THE GULF OF CALIFORNIA WILL DIMINISH BY TONIGHT. FRESH
NORTHERLY GAP WINDS WILL CONTINUE TO PULSE TO STRONG SPEEDS
ACROSS TEHUANTEPEC REGION MAINLY DURING THE OVERNIGHT AND EARLY
MORNING HOURS THROUGH THE NEXT SEVERAL DAYS, WITH SEAS
OCCASIONALLY BUILDING TO 8 FT.
TROPICAL STORM ISELLE IS CENTERED NEAR 16.9N 115.1W AT 23/2100
UTC, MOVING NORTHWEST AT 14 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1001 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO
55 KT. PEAK SEAS ARE 15 FT. NUMEROUS MODERATE TO STRONG CONVECTION
IS NOTED WITHIN 180 NM SW SEMICIRCLE. ISELLE IS MOVING TOWARD
THE NORTHWEST, AND THIS MOTION IS EXPECTED TO CONTINUE THROUGH
MONDAY, FOLLOWED BY A GRADUAL TURN TOWARD THE WEST-NORTHWEST ON
TUESDAY. SOME STRENGTHENING IS FORECAST DURING THE NEXT DAY OR
TWO, AND ISELLE COULD BECOME A HURRICANE MONDAY NIGHT OR EARLY
TUESDAY. SWELLS GENERATED BY ISELLE WILL AFFECT THE WEST COAST OF THE
BAJA CALIFORNIA PENINSULA BEGINNING MONDAY. THESE SWELLS ARE
LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.
CENTRAL EAST PACIFIC (EP91): DISORGANIZED SHOWERS AND THUNDERSTORMS
ARE PERSISTING WITH A BROAD AREA OF LOW PRESSURE LOCATED WELL TO
THE SOUTH-SOUTHWEST OF THE SOUTHERN TIP OF THE BAJA CALIFORNIA
PENINSULA. ENVIRONMENTAL CONDITIONS COULD SUPPORT THE DEVELOPMENT
OF A SHORT-LIVED TROPICAL DEPRESSION DURING THE NEXT COUPLE OF
DAYS BEFORE IT BECOMES ABSORBED BY TROPICAL STORM ISELLE. THIS
SYSTEM HAS A MEDIUM CHANCE FOR TROPICAL CYCLONE FORMATION THROUGH
48 HRS, AND ALSO THROUGH 7 DAYS.
HIGH PRESSURE OF 1024 MB LOCATED NEAR 32N143W EXTENDS A RIDGE
SOUTHEASTWARD INTO THE NORTHERN FORECAST WATERS TO OFFSHORE OF
BAJA CALIFORNIA NORTE. UNDER THE INFLUENCE OF THIS SYSTEM, AND
OUTSIDE OF ISELLE, MODERATE TO LOCALLY FRESH N TO NE WINDS ARE
OBSERVED BASED ON SCATTEROMETER DATA N OF 15N AND W OF 120W.
FRESH NE TO E WINDS ARE SEEN FROM 10N TO 15N W OF 125W. MODERATE
OR WEAKER WINDS AND MODERATE SEAS IN MIXED SWELL PREVAIL
ELSEWHERE.
FOR THE FORECAST, AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP
WELL SOUTH OF THE SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA
DURING THE MIDDLE PORTION OF THIS WEEK. SOME SLOW DEVELOPMENT IS
EXPECTED THEREAFTER, AND A TROPICAL DEPRESSION IS LIKELY TO FORM
LATER THIS WEEK OR OVER THE WEEKEND WHILE THE SYSTEM MOVES
GENERALLY WEST-NORTHWESTWARD. THIS SYSTEM HAS A MEDIUM CHANCE FOR
TROPICAL CYCLONE FORMATION THROUGH 7 DAYS.
SHORT-TERM MAZATLAN TO BAHIA BANDERAS
TODAY - WNW 9-11, Seas SSW 0-4 ft @ 14sec
TONITE - NW 5-6, Seas SSW 0-4 ft @ 13sec
MONDAY - NW 10-12, Seas SSW 1.1-4.1 ft @ 17sec
MONDAY NIGHT - N 7-9, Seas SSW 0-4.1 ft @ 18sec
LONG-TERM MAZATLAN TO BAHIA BANDERAS
TUESDAY - S 14-18, Seas SSW 0-4 ft @ 16sec
WEDNESDAY - ESE 8-10, Seas SW 0-3.1 ft @ 16sec
THURSDAY - NNE 8-10, Seas SSW 1.2-3.2 ft @ 18sec
FRIDAY - WSW 6-7, Seas SSW 0-4.3 ft @ 18sec
SATURDAY - NW 6-8, Seas SSW 0-3.8 ft @ 17sec