000 AXPZ20 KNHC 180955 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Feb 18 2024 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. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A surface ridge building east of the Sierra Madre mountains in Mexico will introduce the next gap wind event in the Tehuantepec region later this morning. Winds are forecast to peak at gale to strong- gale force from this morning through Mon morning. Seas under these winds will range from 10 to 15 ft. Winds will pulse to gale-force into midweek then diminish. Significant NW Swell Event and Gale Warning: A deep and complex 986 mb storm center northwest of the area near 37N140W is generating large swell moving to the southeast of 30N140W. Winds to gale force are ongoing near 30N135W, on the southeast quadrant of the low pressure. The associated swell is reinforcing a previous group of large, long period with 8 to 14 ft combined seas covering much of the discussion area north of 10N and west of 125W. The new group of swell will bring 12 to 23 ft combined seas to the discussion area north of 20N and west of 130W through late today, with higher seas north of area. These seas will subside through late Tue, but not before seas to 12 ft reach the coast of Baja California Norte. Marine interests in the regions above need to monitor these situations and plan their routes accordingly. Please read the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml https://www.nhc.noaa.gov/marine/offshores_eastpac.php for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The surface trough extends from 07N78W to 04N85W to 1010 mb low pressure near 05N95W to 08N105W to 1011 mb low pressure near 05N110W to 04N120W. The ITCZ continues from 04N120W to 01N130W to beyond 02N140W. Scattered moderate convection is evident within 120 nm in the southwest quadrant of the low pressure near 05N95W, and elsewhere within 90 nm north and 120 nm south of the trough between 85W and 95W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section above for information about the upcoming Tehuantepec Gale Warning. A tight pressure gradient between a 1021 mb high pressure off Baja California near 25N122W and lower pressure over southern Mexico is sustaining a patch of fresh N winds off Cabo Corrientes this morning. These winds were detected in a 04 UTC scatterometer satellite pass. Farther south, an area of NW winds moving along the coast of Oaxaca has likely diminished along with associated seas. This will be short-lived however, ahead of the impending push of gale force gap winds expected later this morning through the Gulf of Tehuantepec. Farther north, long-period NW swell is reaching the waters off Baja California Norte, with combined seas building to 8 to 10 ft. Gentle moderate winds and slight to moderate seas are evident elsewhere. For the forecast, as discussed above in the Special Features section, gale- force gap winds will begin in the Gulf of Tehuantepec starting this morning through Mon afternoon, then pulsing to gale-force thereafter into mid week. Seas will build to 15 ft in the Gulf of Tehuantepec by tonight. Farther north, large, long- period NW swell is reaching the Baja California Norte offshore waters, and will spread to near the Revillagigedo Islands by tonight. This swell will be reinforced with a second group of large, long- period NW swell reaching Guadalupe Island and Baja California Norte by Mon night with combined seas to 14 ft. Looking ahead, the swell will subside through late Thu while gap winds across the Gulf of Tehuantepec diminish. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR A few thunderstorms are active north of the near-equatorial trough off the west coast of the Azuero Peninsula of Panama, and also near Cocos Island off Costa Rica. Gentle breezes and moderate seas are ongoing across the region for now. For the forecast, fresh winds and moderate to locally rough seas will impact the offshore waters of Guatemala later today. Large NW swell generated from a nearby gale-force gap wind event will impact the waters of Guatemala and El Salvador thereafter through mid week. Expect gap winds and rough seas in the Papagayo region and Nicaragua tonight into the latter part of the week, as a ridge builds over the northwestern Caribbean. Farther south, fresh N winds and building seas are expected over the Gulf of Panama Tue night through Thu night. ...REMAINDER OF THE AREA... Please read the Special Features section above for information about the ongoing significant swell event and gale warning. A recent scatterometer satellite pass confirmed near-gale to gale force winds accompanying a cold front analyzed from 30N135W to 26N140W. Concurrent altimeter satellite data showed the start of the next big swell group, with 12 to 15 ft south of 30N and up to 23 just outside of the discussion area. Farther east, a previous frontal boundary is stalled and starting to weaken between 125W and 130W north of 25N. East of that front, 1021 high pressure is centered near 25N122W. Elsewhere large, long- period NW swell in excess of 8 ft extends over the waters north of 05N and west of 120W. Combined seas are 5 to 7 ft elsewhere. Moderate winds are evident in most areas, except as noted near the reinforcing front. For the forecast, the high pressure will gradually drift southward and weaken through the weekend, which should allow winds north of the ITCZ/trough to subside through Tue. The fronts will merge today into one front, which will continue to drift east north of 20N while weakening through Thu. High pressure building southeastward behind the merged front will cause winds and seas north of the ITCZ to increase again by midweek next week. Winds and seas will diminish across the region by late week, except for over the waters north of 20N and west of 130W when another NW swell event enters the area. $$ Christensen