000 AXPZ20 KNHC 140311 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Apr 14 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong high pressure will surge southward along the Sierra Madre Oriental mountains on Sun in the wake of strong late season cold front that will move across the western Gulf of Mexico. The strong high pressure will allow for a very tight pressure gradient to set up over southeastern Mexico. This will induce strong gale force N-NE winds in the 30-45 kt range into the Gulf of Tehuantepec commencing early on Sunday. This event is expected to continue into early next week, while gradually diminishing. Seas as high as about 17 or 18 ft are expected Sun night into Mon, before slowly subsiding early next week. In adittion, an extensive swath of large NE to E swell will propagate well to the southwest and west of the Tehuantepec area reaching near 11N100W by Sun night. 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 10N85W to 07N95W to 05N103W. The ITCZ continues from 05N103W to 08N120W to 06N130W to 06N140W. Scattered moderate convection is noted within 120 nm N of ITCZ between 118W and 122W, and within 60 nm between 132W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to locally strong NW winds and large NW swell will prevail west of Baja California Norte tonight and Sat. Strong NW winds are forecast across the length of the Gulf of California through early Sun in association with a strong high pressure over the Great Basin. A late season Gulf of Tehuantepec gap wind event will be induced by a strong cold front moving across the Gulf of Mexico starting Sun, continuing into Tue morning. Please, see Special Features section for details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds are expected through the forecast period. Seas in the 3 to 4 ft range will continue over most of the area. Fresh gap winds are likely in the Gulf of Papagayo tonight, and possible again early on Mon. REMAINDER OF THE AREA... The pressure gradient between lower pressure in the vicinity of the ITCZ and strong high pressure of 1035 mb centered N of the area near 35N130W is producing fresh to strong trade winds north of the ITCZ and west of 125W. The aerial extent of the trades will diminish late on Sat as the high pressure weakens some. Large NW swell is propagating southeastward through the forecast waters, with max seas of around 14 ft in the north-central waters based on latest altimeter data. This swell event will continue to propagate SE across the forecast waters, particularly W of 108W over the next 48 hours. A cold front will sweep into the NW waters on Sun. Fresh to locally strong N to NE winds will follow the front forecast to weaken over northern waters on Mon. $$ GR