Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Nov 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Large NW swell over the northern waters: A cold front enters the discussion waters near 30N119.5W to 25N126W to 25N140W. The front has ushered in a large set of NW swell. Very rough seas greater than 12 ft with wave periods of 12-14 seconds will cover the northern waters N of 29N and W of 125W this morning. Seas greater than 12 ft will then shift SE across the waters N of 26N and W of 117W through Sat before subsiding below 12 ft. Seas will peak near 17 ft tonight. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N84W to 07N122W. The ITCZ extends from 07N122W to 07N140W. Scattered moderate and isolated strong convection is noted from 05N to 09N between 78W and 85W. Scattered moderate convection is from 05N to 08N and W of 132W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on a large NW swell event. A cold front is analyzed from 30N117W to 24N130W to 26N140W. Moderate to fresh NW winds are noted west of the front, and fresh SW winds prevail in the northern Gulf of California waters. Light to gentle winds generally prevail elsewhere. Seas are in the rough range N of 28N while moderate seas prevail elsewhere. Slight seas prevail over the Gulf of California. For the forecast, a secondary push of cold air accompanied by an area of low pressure will quickly follow the cold front tonight through Sat night, generating fresh to strong NW to W winds with scattered showers and isolated thunderstorms west of Baja California Norte. Its associated front will usher in a set of large NW swell, which will spread over the waters west of the baja California peninsula, and southward to the Revillagigedo islands through Mon before starting to subside. Fresh to strong N gap winds can be expected over the Gulf of Tehuantepec from Sat night to Sun night. Elsewhere, benign marine conditions are expected. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds prevail over the Gulf of Papagayo. Light to gentle winds are elsewhere N of the monsoon trough. Gentle to moderate winds prevail S of the monsoon trough. Seas are in the moderate range. For the forecast, moderate to fresh NE to E winds are expected over and downstream of the Papagayo region into early next week. Moderate or lighter winds are forecast elsewhere during the forecast period. ...REMAINDER OF THE AREA... Please see the Special Features section for details on a large NW swell event. A cold front extends from 30N117W to 24N130W to 26N140W. Moderate to fresh winds prevail N of the front. A 1032 mb high pressure is centered near 35N141W. The pressure gradient between the area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh to strong winds N of the ITCZ to near 21N and W of 130W. Seas over these waters are in the rough to very rough ranges. Gentle to moderate winds, and moderate seas prevail elsewhere. The cold front will progress quickly southeastward today, and is forecast to dissipate by Sat morning as it reaches 20N. Fresh to strong winds north of 25N on today will diminish below fresh Sat. Rough seas of 8 ft or greater generated from the frontal system will propagate across the area, covering much of the discussion waters N of 08N and W of 115W this weekend before starting to slowly subside early next week. The area of high pressure northwest of the discussion waters will weaken tonight and Saturday. This will loosen the pressure gradient over the tradewind zone, with the trades diminishing.