000 AXPZ20 KNHC 311602 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Mar 31 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 1200 UTC surface analysis and satellite imagery through 1545 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 beginning late today into Thu. The resultant tight gradient between it and lower pressure south of Mexico is expected to result in a surge of strong gale-force winds in the Gulf of Tehuantepec region starting late tonight into early Thu 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 afternoon. Wave heights will build to 10-14 ft Thu and to 12-18 ft Thu night through late 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 09N86W to 05N90W to 04N95W, where overnight scatterometer data indicates that it transitions to the ITCZ to 05N108W to 05N117W to 04N126W. It resumes at 04N130W to 03N140W. Scattered moderate convection is seen from 05N to 08N between 123W and 127W. 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. A surface trough west of Clarion Island is resulting in a weak pressure pattern across the region north of 20N. This pattern is supporting gentle to moderate winds throughout the Mexican offshore waters north of 20. Seas are 3 to 4 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, moderate winds across the Gulf of Tehuantepec will abruptly become strong gale force north to northeast winds beginning late tonight into early Thu 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 Sun afternoon. Swell generated by this event will spread well to the southwest and west of the Gulf of Tehuantepec region through the weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... A thin volcanic ash plume originating over the interior of Guatemala from the Fuego Volcano located over southern Guatemala near 14.5N 90.9W is observed on satellite imagery spreading southwestward across the Pacific coast of Guatemala between 13N and 14N, but may not be sinking to near the surface at the present time. Fresh northeast winds are about 200 nm downstream of the Papagayo area, indicating stronger gap winds are likely ongoing closer to shore. Seas are likely up to 8 ft in the plume of gap winds, with a component of longer-period SW swell. 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 nearly stationary upper-level low is identified on water vapor imagery to be near 26N124W. Mid to upper-level moisture is present to the east of the low. A few showers and thunderstorms are ongoing are possible from 26N to 28N between 125W and 130W. This mid to upper level trough from 21N120W to 26N125W, and farther south into the tropics, from 04N127W to 10N118W. Scattered showers and a few thunderstorms are active from 05N to 08N between 123W and 127W. Moderate to fresh trade winds and 8 to 9 ft seas are evident from 05N to 18N west of 130W. SW swell is supporting 5 to 7 ft seas east of 130W, south of 20N. N swell is propagating into the waters north of 25N between 120W and 130W, and 5 to 7 ft seas in mixed swell elsewhere. For the forecast, the swell north of 25N will subside through Thu. Winds will diminish west of 130W as high pressure north of the area weakens. Seas to 8 ft will persist over 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. The upper low near 25N125W will dissipate, allowing winds and seas to dissipate Wed. $$ Aguirre