000 AXPZ20 KNHC 132142 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Apr 13 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 2145 UTC. ...SPECIAL FEATURES... 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 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 19 or 20 ft are expected Sun night into Mon, before slowly subsiding early next week. Also of significance in regards to this upcoming event is that a very extensive swath of large NE to E swell will propagate well to the southwest and west of the Gulf of Tehuantepec, excepted to reach near 115W northward to 15N and southward to near 02N early next week. Please stay tuned to future E Pacific high seas forecasts that will provide details on this upcoming strong gale event. The E Pacific high seas forecast can be accessed under AWIPS/WMO headers HSFEP2/FZPN03 KNHC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 10N85W to 08N93W to 09N101W. The ITCZ continues from 09N108W to 09N120W to 07N131W to 06N140W. Scattered moderate isolated strong convection is noted within 60 nm south of the ITCZ between 122W and 124W, and within 60 nm south of the ITCZ between 126W and 128W. Scattered moderate convection is within 60 nm south of the ITCZ between 122W and 124W, and also within 30 nm of the trough between 87W and 89W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to strong NW winds and large NW swell will prevail west of Baja California Norte today. Strong NW winds are forecast across the length of the Gulf of California through early Sun. Strong N to NE gale force winds will begin over the Gulf of Tehuantepec starting Sun, continuing into Tue morning. 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 starting Tue. REMAINDER OF THE AREA... The pressure gradient between lower pressure in the vicinity of the ITCZ and strong high pressure centered N of the area near 34N131W is producing moderate to fresh trade winds north of the ITCZ and west of 110W. Strong high pressure ridging will build east- southeastward through Sat, with a tighter gradient increasing the trade winds across the tropical Pacific. Large NW swell is propagating southeastward through the forecast waters, with max seas of around 14 ft in the northeastern part of this section of the area, will slowly diminish through Mon night. A cold front will sweep into the northwestern waters Sun. Fresh to strong N to NE winds will follow in behind the front over the far northwestern corner of the area, The front will weaken over northern waters on Mon, however, the fresh to strong NE to E winds will continue over much of the northwestern portion of the area, and over portions of the far western portion as well. $$ Aguirre