000 AXPZ20 KNHC 162159 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2045 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. A midday scatterometer pass provided observations of 30-40 kt across the Tehuantepec region and downwind to near 13.5N. Winds are assumed to have diminished slightly this afternoon to just below 40 kt, and are forecast to increase slightly to around 40 kt tonight, then gradually diminish to 30-35 ft by early Tue morning. Seas of 10-15 ft are estimated downstream of Tehuantepec this afternoon, and will begin to gradually subside to below 15 ft late 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 03N to 16N between 93W and 110W by Tue afternoon. Winds are forecast to fall below gale force 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 09.5N71.5W TO 10.5N77W TO 05N94W. The ITCZ stretches from 05N94W TO 06.5N125W to beyond 06.5N140W. Scattered moderate isolated strong convection is noted within 180 nm S of the trough between 87W and the coast of Colombia. Scattered moderate to strong convection is noted within 180 nm N and 120 nm S of the ITCZ between 100W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate NW to N winds prevail across the offshore waters W of Baja California this afternoon, with strongest winds N of Punta Eugenia. 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 across much of the Gulf are freshening across N portions this afternoon, and 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 NW winds are then expected to prevail across the Gulf through Wed through Fri. 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 late afternoon through early morning hours each day 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. Cross equatorial SW swell will mix with residual swell from Papgayo Tue night through Fri and raise seas to 5-7 ft S of 10N. REMAINDER OF THE AREA... A cold front is moving SE across the northern waters and extends from the California-Mexico border to 20N120W to beyond 25N132W where it has begin to stall along 24N140W. Mainly low clouds are associated with the frontal boundary. The front will continue to move SE across the northern waters E of 120W this evening and tonight and gradually weaken. Fresh to locally strong N to NE winds follow the front. A 1033 mb high pressure center is located near 36N146W behind the front and will move SE bringing fresh to strong NE-E winds across the waters W of 125W this afternoon and tonight. Large NW swell continues to propagate southeastward through the forecast waters, with max seas of around 11 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 105W 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 97W by early Tue evening. $$ Stripling