000 AXPZ20 KNHC 161554 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Apr 16 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 1445 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. An overnight scatterometer pass provided observations of 35-45 kt across the Tehuantepec region and downwind to near 13N. winds are assumed to have diminished slightly this morning to 30-40 kt, and are forecast to persist today through tonight, then gradually diminish to 30-35 ft by early Tue morning. Seas of 10- 17 ft are estimated downstream of Tehuantepec this morning, and will begin to gradually subside to 10-15 ft by tonight. An extensive swath of large N to NE swell generated by these northerly winds will continue to propagate well to the SW of the Tehuantepec area, covering roughly the waters from 08N to 15N between 93W and 105W by this afternoon. This has been a strong late season Gulf of Tehuantepec gap wind event. Winds are forecast to be below gale force by late Tue morning. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 09N74W TO 10.5N81W TO 08.5N94W. The ITCZ stretches from 08.5N94W TO 06N113W TO 07N124W to beyond 04N140W. Scattered moderate to strong convection is noted from 03.5N to 08N E of 79W to coastal Colombia. Similar convection is also noted within 150 nm N and 180 nm S of the ITCZ between 97W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate to fresh NW to N winds will prevail across the offshore waters W of Baja California, and mainly N of Cabo San Lazaro during the next several days. Winds will briefly increase to 20-25 kt mainly N of 28N and E of 118W tonight as a weakening cold front moves across the northern Baja California peninsula and the northern Gulf of California. Seas will remain in the 8- 10 ft range across the offshore waters through mid-week. Gulf of California: Moderate southerly winds this morning will increase to 20-25 kt across the northern Gulf of California ahead of a cold front crossing the area tonight. Then, fresh to strong NW-N winds are expected behind the cold front early on Tue. Gentle to moderate winds are forecast across the remainder of the Gulf much of the forecast period. Gulf of Tehuantepec: A strong late season Gulf of Tehuantepec gap wind event was induced by a strong cold front moving across the Gulf of Mexico during the previous days. Please, see Special Features section above for details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Pulsing fresh to strong NE-E winds are expected across and downstream of the Gulf of Papagayo during the overnight and early morning hours through Fri. Gulf of Panama: Moderate to fresh northerly winds are expected across the Gulf of Panama at night, beginning tonight through Wed night. Elsewhere, light to gentle winds are expected through the forecast period, with a weak surface through extending along 08- 09N yielding light S to SW winds to its south. Seas in the 3 to 5 ft range will continue over most of the area. REMAINDER OF THE AREA... A cold front is moving SE across the northern waters this morning, and extends from 30N123W to 26N132W and then is beginning to stall to near 24.5N140W. Mainly low clouds are associated with the frontal boundary. The front will continue to move SE across the waters E of 120W and gradually weaken today and tonight. Fresh to locally strong N to NE winds follow the front. A 1034 mb high pressure center is located near 36N149W behind the front and will move SE bringing fresh to strong NE-E winds across the waters from 19N to 27N W of 130W by this afternoon. Large NW swell continues to propagate southeastward through the forecast waters, with max seas of around 12 ft in the far western waters N of the ITCZ. This swell will mix with waves generating in the Tehuantepec area today through Wed. As a result, seas of 8 ft or greater will cover much of the forecast region W of 108W today, and most of the area W of 110W on Tue. Cross equatorial SW swell is forecast to reach the southern forecast waters by Tue morning. Marine guidance suggests that seas of 8-9 ft will dominate the waters S of 04N to the W of 100W by early Tue evening. $$ Stripling