000 AXPZ20 KNHC 010723 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Apr 1 2021 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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 0830 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong high pressure in the wake of a Gulf of Mexico cold front, will build southward along the eastern slopes of the Sierra Madre Oriental mountains of Mexico through today. The resultant tight gradient between it and lower pressure south of Mexico will result in a surge of strong gale- force winds in the Gulf of Tehuantepec region this morning as a cold front quickly moves over the western Gulf of Mexico and across southeastern Mexico. These gale conditions are expected to continue into the upcoming weekend, diminishing to just below gale force on Sun night. Wave heights will build to 10-14 ft today and to 12-18 ft tonight through Fri, before they begin to slowly subside through Sun. Swell generated by this event will spread well to the southwest and west of the Gulf of Tehuantepec region through the weekend. Mariners navigating through these waters are urge to use caution as these impending conditions are likely to lead to hazardous marine conditions. Please read the latest HIGH SEAS FORECAST- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Volcanic Ash Advisory: The Picaya Volcano in southern Guatemala located near 14.4N 90.6W is currently erupting and is producing a plume of volcanic ash observed to be spreading out across the offshore waters of Guatemala. The ash may reaching the surface of the ocean, and may be reducing visibility to some extent. While there have been no reports of volcanic ash reaching the surface or reduced visibilities, mariners are still urged to exercise caution and report and observations to the National Hurricane Center by calling 305-229-4425. Please read the latest HIGH SEAS FORECAST- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details on both the Gale Warning and on the Volcanic Ash Advisory. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 10N85W to 05N92W. The ITCZ to 04N94W to 05N108W to 05N125W to 02N140W. No significant convection is noted. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on an upcoming gap gale-force wind event in the Gulf of Tehuantepec region and on the Picaya Volcano. A relatively weak pressure pattern is over the area north of 20N. This pattern is supporting gentle to moderate winds throughout the Mexican offshore waters north of 20N. Seas are 3 to 5 ft north of 20N, except 5 to 7 ft in NW swell off Baja California Norte. South of 20N, seas 5 to 7 ft in SW swell. For the forecast, high pressure building west of Baja California will allow fresh NW winds off Baja California Norte Sat and Sun. Gentle to moderate NW winds will persist elsewhere in Mexican offshore waters outside of the Tehuantepec region. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... A Volcanic Ash Advisory is in effect for the Picaya Volcano in southern Guatemala. See Special Features above. A recent scatterometer satellite pass confirmed fresh northeast winds into the Gulf of Papagayo area. Seas are likely up to 8 ft in the plume of gap winds, with a component of longer- period SW swell. Fresh N gap winds are likely active across the Gulf of Panama, with a plume reaching as far south as 05N in 5 to 7 ft seas. Elsewhere light to gentle winds continue over the Central American offshore waters with 3-5 ft wave heights. For the forecast, fresh to strong offshore gap winds will continue across Gulf of Papagayo region through Sun night. Seas will build from northern Costa Rica to Guatemala by Thu, due to seas generated from the Papagayo and Tehuantepec gap wind areas mixing with longer-period SW swell. REMAINDER OF THE AREA... A broad ridge persists across the waters north of 20N. Recent scatterometer satellite data shows gentle to moderate breezes across this area, but a pair of recent altimeter satellite passes indicated 6 to 8 ft seas north of 20N and west of 118W. This is due to lingering northerly swell. Moderate to fresh NE trade winds persist from 05N to 20N, west of 125W, with 7 to 9 ft seas due in part to mixed swell. Farther east, seas are reaching 8 ft near 05N95W, due to NE to E swell emerging from gap areas farther east, and longer period SW swell. Gentle to moderate E winds and 5 to 7 ft seas persist elsewhere. For the forecast, fresh trade winds will diminish temporarily today, then will expand eastward across the deep tropics. This will support seas to 8 ft will across the deep tropics through the latter part of the week with a component of northerly swell west of 120W, and in a mix of SW and NE swell east of 120W. $$ Christensen