000 AXPZ20 KNHC 010731 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 612 UTC Sun Apr 1 2018 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A recent scatterometer pass confirmed the presence of minimal gale force winds across the Gulf of Tehuentepec and downwind to near 14N95W. Fresh to strong northerly winds are blowing roughly over the waters N of 13N between 94W and 96W. Winds are forecast to diminish below gale force by this morning as the ridge along the Sierra Madre Oriental shifts eastward. In response to the shifting of high pressure, winds over the SW Gulf will veer to the E, and then SE. This will further diminish winds funneling through the Chivela pass into the Gulf of Tehuantepec and bring an end to this latest gap wind event, with winds diminishing below 20 kt by this evening. Marine guidance suggests that another minimal gale force wind event may occur across the Gulf of Tehuantepec late Wed into Thu. Please refer to the High Seas Forecast issued by the National Weather Service under AWIPS/WMO headers MIAHSFEP2/ FZPN03 KNHC for more details. This information is also found at the following website: www.hurricanes.gov/marine. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... During March and April of each year, a doble ITCZ is usually present in the Southern Hemisphere on the eastern Pacific basin. Based on this pattern no monsoon trough is currently present E of 140W. Only a surface trough is analyzed from 09N84W to 05N90W to 05N103W. Then, the ITCZ axis continues from 05N103W to 06N120W to 05N140W. A second ITCZ axis is seen S of the Equator and extends from 05S83W to 03S94W to 05S105W to 02S126W. Scattered moderate convection is noted from 11N to 14N between 108W and 113W, and from 08N to 10.5N between 113W and 116W. Similar convection is observed S of the Equator from 03S to 06S between 98W and 104W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for more information on the latest Gulf of Tehuantepec gale force gap wind event. Elsewhere, a weak pressure pattern will prevail over the forecast area today. This will maintain mainly light and gentle winds over the open waters off the SW coast of Mexico as well as W of the Baja California Peninsula. Seas of 3 to 6 ft will prevail over these waters. High pressure will start to build closer to the forecast area early on Mon. This will bring a slight increase to winds, with gentle to moderate NW to N winds developing across the offshore waters W of Baja California. In response to the increase in winds, seas will build to 4 to 7 ft over this area through the middle of the next week. Gulf of California: Mainly light to gentle winds will prevail over much of the gulf the next several days. Winds will increase to gentle to moderate over the northern gulf tonight through Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Winds will pulse to fresh to locally strong through Sun morning, with seas building to near 8 ft downstream of the gulf. Gulf of Panama: Winds will pulse to fresh to locally strong across the western part of the gulf, and near the Azuero peninsula through Sun morning. Elsewhere, gentle to moderate offshore flow is generally expected N of 09N through Tue, while light and variable winds are forecast S of 09N. REMAINDER OF THE AREA... A 1026 mb high pressure located near 40N134W extends a ridge SE across the forecast waters to near the Revillagigedo Islands while a 1018 mb low pressure is over the far NW corner of the forecast area. Under this weather pattern, mainly gentle to moderate winds prevail, reaching near 20 kt just N of the ITCZ and west of 130W, with seas to 7 ft based on altimeter data. The weak pressure pattern will prevail through the middle of next week, resulting in winds of 20 kt or less, and seas less than 8 ft. $$ GR