000 AXPZ20 KNHC 141603 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Nov 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Storm Warning: A very tight pressure gradient over southern Mexico and the Isthmus of Tehuantepec is associated with strong high pressure cells of 1034 to 1039 mb centered over northeastern Mexico, and while a strong cold front moves across the eastern and central Gulf of Mexico. This synoptic set-up is producing storm force winds over the Gulf of Tehuantepec as verified in scatterometer data from last night. Model guidance at 10m and at 925 mb suggests that this event will last through early Thu, at which time the high pressure will weaken just enough to allow for the storm force winds to diminish to strong north to northeast gale force winds in the range of the 35 to 45 kt. Large seas in the range of 19-21 ft are resulting from these storm conditions. Strong gale force north to northeast winds of 30 to 40 kt are within 60 nm either side of a line from 16N95W to 12N96W with seas in the range of 10 to 17 ft. Quite impressively, is that north to northeast of 20 to 30 kt extend as far south of 09N between 91W and 100W. The post-storm gale force winds are forecast to persist until early Sat morning, then pulse again Sun night. A large swath of high seas from this event will propagate south and southwest of the Gulf of Tehuantepec region, with the leading edge of the 8 ft seas forecast to reach near 108W by Fri. ...TROPICAL WAVES... A tropical wave has its axis along 128W from 05N to 17N, moving westward at 10 to 15 kt. Scattered moderate isolated strong convection is seen within 240 nm east of the axis from 08N to 10N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia to 08N79W to 08N91W to 08N100W to 09N111W, where latest scatterometer data indicates the ITCZ axis begins and continues to 08N124W, where it briefly ends before resuming west of tropical wave along 128W, and continues to beyond the area at 06N140W. Scattered moderate convection is seen within 120 nm south of the trough axis between 78W and 80W, within 60 nm south of the axis between 130W and 133W and also between 133W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for the ongoing Gulf of Tehuantepec storm event. Strong high pressure over the SW United States and Mexico will support fresh to locally strong northerly winds over the Gulf of California through this morning. Fresh to strong NE winds and seas of 8 to 9 ft will continue west of Baja California N of Cabo San Lazaro this morning, then subside by this evening. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds over the Gulf of Papagayo will increase late tonight as a tight pressure gradient develops over northern Central America behind a strong cold front that is currently over the eastern and central Gulf of Mexico, and that will move into the northwestern Caribbean. Seas will build to 9 ft Thu morning. This gap wind event is expected to continue through the upcoming weekend. A strong Tehunatepec gap wind event west of the area is forecast to spread strong winds and high seas in the range of 12 to 18 ft into Guatemala and El Salvador offshore waters west of 92W through Thu morning. Cross-equatorial long period SW swell will maintain seas around 6 to 7 ft between Ecuador and the Galapagos Islands to near the Azuero Peninsula through tonight. REMAINDER OF THE AREA... High pressure of 1029 mb north of the area and centered to the west of California near 35N130W and moving NW at 15 kt extends a ridge southeastward to near the Revillagigedo Islands. The pressure gradient between the high and lower pressure in the vicinity of the ITCZ will support fresh to strong trades north of the ITCZ west of 124W, with seas of 8 to 10 ft. These conditions are forecast to shift westward and slowly diminish through Thu. NW swell associated with an earlier stationary front that recently dissipated is producing 8 to 9 ft seas over the northwestern waters. By early Thu, this swell will merge with those generated from wind waves generated by the area of fresh to strong trades. The remnants of the dissipated stationary front is presently analyzed as a trough from 30N143W to 34N140W. This trough will pull off the the northwest and north through early Thu while becoming diffuse. Model guidance depicts that the next cold front will approach the far northwestern corner of the area on Fri. Cross-equatorial long period SW swell is bringing seas of 7 to 8 ft south of 02N between 108W and 121W. This area of seas will gradually shrink through Thu, with seas lowering to 8 ft. $$ Aguirre