000 AXPZ20 KNHC 230740 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 905 UTC Sun Dec 23 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Winds will increase over the area later today, with gale conditions expected tonight through Mon night as an area of high pressure builds southward over southern Mexico. The forecast calls for peak winds of 30-40 kt and seas of 10-14 ft on Sun night. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZNPN03 for more specific marine details. Gulf of Papagayo Gale Warning: High pressure building southward over the northwestern Caribbean Sea is inducing a tight pressure gradient over northern Central America, which is resulting in minimal gale force winds over the Gulf of Papagayo. These winds are forecast to diminish to below gale force later this morning. Fresh to strong winds are then expected across the Gulf of Papagayo through at least the middle of the week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from the coast of Colombia near 05N77W to 04N82W and to 06N90W. The ITCZ continues from 06N90W to 05N110W to 07N125W to beyond 07N140W. Scattered moderate convection is from 05N to 08N between 92W and 98W, and from 07N to 13N between 125W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features Section above for information on the next gale force gap wind event over the Gulf of Tehuantepec. Another set of long period NW swell is propagating across the NW forecast waters. This swell event is forecast to reach the offshore waters of Baja California Norte by early on Mon, and the remainder of the Baja California Peninsula offshore waters by early on Tue. Marine guidance indicates that seas will build to 12 to 16 ft N of Punta Eugenia on Tue. By that time, fresh to strong NW winds are also forecast to affect the offshore waters N of 26N. These winds will increase to strong to near gale-force by Tue evening before diminishing early Wed. Gulf of California: Winds are light and variable across the area with the typical climatological trough meandering along the west coast of mainland Mexico. Overall, little changes are expected with these conditions through Mon night. Deepening low pressure will move across the southwestern United States on Tue as high pressure intensifies west of Baja California. This scenario will cause the pressure gradient to tighten over northern Baja California and the northern Gulf of California on Tue leading to near gale force winds across the northern Gulf of California Tue, and brief gale-force winds Tue night. Seas will peak near 8 or 9 ft by Tue night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features Section for more on the gale force gap wind event over the Gulf of Papagayo. Strong north winds will continue over the Gulf of Panama through Sun night, with seas building to 8 ft by early Sun. Elsewhere, gentle to moderate winds will prevail, with seas in the 4 to 7 ft range. REMAINDER OF THE AREA... The pressure gradient between high pressure of 1027 mb centered near 33N131W and lower pressures present near the ITCZ is producing fresh to strong northeast trades from 08N to 20N W of 137W along with seas ranging from 8 to 11 ft as confirmed by altimeter data. This area of trades and associated seas will expand north and east through early next week as this meandering high pressure located N of 30N intensifies. A set of NW swell will propagate from 31N140W this morning and spread quickly southeastward, with 8 to 11 ft seas reaching to a line from 30N120W to 08N140W by early Mon, then covering the waters N of 08N and W of 115W by early Tue. As this swell begins to diminish midweek, another set of reinforcing NW swell will arrive near 31N140W. The combination of cross equatorial swell and NE swell associated with the Gulf of Tehuantepec and Gulf of Papagayo winds will result in seas of 8 to 9 ft generally S of 10N between the Galapagos islands and 120W through Mon. $$ Latto