000 AXPZ20 KNHC 310402 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0300 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 Wed 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 Wed night into 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. Wave heights will build to 10-14 ft Thu and to 12-18 ft Fri and Fri night, before they begin to slowly subside Sat. Swell generated by this event will spread well to the southwest and west of the Gulf of Tehuantepec region through the weekend. Please read the latest HIGH SEAS FORECAST- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 09N85W to 04N93W. The ITCZ extends from 04N95W to 05N118W, and from 05N128W to 04N140W. Scattered moderate convection is observed 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. Gentle to moderate winds persist throughout the Mexican offshore waters, except for moderate to fresh NW winds off Cabo Corrientes. Seas are 5 to 7 ft off Oaxaca and Chiapas in SW swell, with 4 to 6 ft farther north in open water in a mix of SW and NW swell. Moderate to fresh north to northeast winds in the Gulf of Tehuantepec region will become light and variable later this afternoon and moderate south to southwest winds tonight. A small area of lingering wave heights to 8 ft is downstream of the Gulf of Tehuantepec. These wave heights will gradually shift westward away from the Gulf of Tehuantepec region through early Wed while subsiding to less than 8 ft. Wave heights are 4-6 ft elsewhere off southern Mexico south of Cabo Corrientes due to a S to SW swell, with light to gentle breezes. Farther north, gentle to moderate NW winds persist with wave heights of 3-5 ft seas in open waters with mixed SW and NW swell. For the forecast, moderate winds across the Gulf of Tehuantepec will abruptly become strong gale force north to northeast winds beginning late Wed night into 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... Strong NE to E winds are across the Gulf of Papagayo, with wave heights up to about 8 ft as well as downstream of the plume of these winds. They are combining with a component of longer- period SW swell. An recent scatterometer satellite pass from late this morning revealed gentle to moderate north winds through the Gulf of Panama. 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 the period. Seas will build from northern Costa Rica to Guatemala later in the week, 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 25N125W. 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. $$ Christensen