000 AXPZ20 KNHC 231600 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1600 UTC Fri Feb 23 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Ashfall Advisory: The Fuego Volcano at 14.5N 90.9W over S Guatemala is erupting. A plume of volcanic ash may reach to the surface through tonight N of 14N and E of 93W. Low level visibilities may be reduced to 1 nm. Mariners should exercise caution. If mariners encounter volcanic ash, they are encouraged to report the observation to the National Weather Service by calling 305-229-4425. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details on the ashfall advisory. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends SW from the Pacific coast of Costa Rica near 10N84W to 04N92W to 01N104W. The ITCZ axis continues from 01N104W to 06N120W to 07N140W. Scattered moderate and isolated strong convection is within an area bounded by 06N117W to 04N116W to 03N119W to 04N129W to 06N129W to 07N124W to 06N117W, and also within an area bounded by 14N118W to 10N124W to 08N131W to 10N137W to 13N133W to 17N116W to 14N118W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... In the Gulf of Tehuantepec, northerly winds at fresh to strong levels this morning will diminish by the afternoon. Seas of 6-8 ft will subside as the winds diminish. In the Gulf of California, light and variable winds in the northern Gulf prevail with moderate to fresh NW to N winds in the central and southern Gulf. Strengthening high pressure will develop fresh to strong NW winds across the far northern waters tonight with these conditions spreading southward across the central and southern Gulf by early Sat through Sat night. Seas may build to up to 8 ft during the strongest winds. The pressure gradient will relax on Sun and Mon. The next cold front will approach Mon night and winds will become southerly ahead of it in the northern Gulf while increasing to fresh to strong Mon night through Tue, with fresh northerly winds behind the front as it sinks southward through the early part of the week. Across the remainder of the open offshore waters of Mexico, a ridge axis extends from NW to SE. Moderate to fresh northerly winds are observed W of the Baja Peninsula with seas of 5 to 7 ft. Strengthening high pressure will increase the winds to fresh to strong this afternoon, with seas building to 7-10 ft in fresh NW swell. The conditions will gradually spread southward offshore of the Baja California peninsula through Sat morning, diminishing thereafter. The associated seas should subside to less than 8 ft by early Mon, with another round of fresh to strong NW winds, accompanied by large NW swell, arriving at 30N120W early Tue with the next cold front. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to strong NE winds will continue to pulse offshore across the Gulf of Papagayo through early next week, with seas occasionally building to 7-9 ft as downstream as 10N91W. In the Gulf of Panama, fresh nocturnal N winds are expected across the western Gulf of Panama tonight with these conditions extending as far S as 05N80W. Mostly moderate nocturnal drainage flow is then forecast on Sat and Sun nights with fresh winds expected to resume on Mon night. Elsewhere, gentle to moderate offshore flow will prevail N of 08N while light to gentle SW winds are forecast S of 08N. REMAINDER OF THE AREA... Strong high pressure well NW of the area will continue to support fresh to strong NE trades and seas up to 8-12 ft across the tropical waters N of the convergence zone and W of 110W through the upcoming weekend when the pressure gradient is forecast to further tighten. A fresh batch of northerly swell in the form of 7-11 ft seas will propagate S of 32N today reaching along 22N between 115W and 130W on Sat before beginning to subside. Strong northerly winds will reach along 32N between 123W and 132W late Mon and spread S along 27N early Tue associated with the next cold front. $$ Lewitsky