000 AXPZ20 KNHC 152206 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Dec 15 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... Gulf of Tehuantepec Gale Warning: The tight pressure gradient over southeastern Mexico resulting from the combination of strong high pressure over northern Mexico and lower pressure south of Mexico is bringing strong gale force northerly winds over the Gulf of Tehuantepec with seas to 16 ft. This strong gap wind event will continue through Sun night, before diminishing on Mon as the strong high pressure over Mexico shifts eastward and weakens. Seas with this event will subside to 9 to 13 ft Mon and to less than 8 ft on Tue as the northerly winds diminish to fresh speeds. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more specific marine related details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwestern Colombia to 06N77W to 05N93W, where latest scatterometer data indicated that it transitions to the ITCZ and continues to 05N93W to 05N110W to 08N128W to 07N140W. Scattered moderate convection is noted from 10N to 21N W of 112W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak ridge will preavil over the area maintaining light to gentle breezes across the area. Northwest swell with seas to 9 ft will persist in the offshore waters of Baja California through Sun. A cold front will approach the region Mon bringing a new set of northwest swell, with seas from 12 to 16 ft reaching the northern coast of Baja California Norte and Guadalupe Island by Mon. Swell of 12 to 15 ft will cover the Baja offshore waters to the Revillagigedo Islands into mid week. Swell of this size and period will present hazardous seas for mariners, cause very powerful and dangerous surf along the Pacific reefs and beaches, and likely produce areas of modest coastal flooding and beach erosion. Over the Gulf of California, strong high pressure north of region have been supporting moderate to fresh breezes across the basin. A mid to upper-level disturbance approaching the area from the west may bring a few showers to the central and southern portions of the Baja California Peninsula and Gulf of California through Sun. Strong high pressure will build N of the area by the middle of the week and will support fresh to strong winds across the gulf. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Fresh to strong gap winds will pulse starting tonight and persist into early next week as high pressure builds north of the area. The gap winds will diminish late Tue night. These winds will diminish to mainly fresh speeds Wed night. Seas with these winds are expected to be 8 to 9 ft. Fresh winds will also pulse across the Gulf of Panama and Gulf of Fonseca tonight and Sun. Elsewhere, gentle to moderate winds will persist on either side of the monsoon trough through early next week, as seas remain in the 4 to 6 ft range. REMAINDER OF THE AREA... A mid to upper-level trough north of about 18N between 115W and 134W is supporting scattered moderate convection and a surface trough. Seas are as high as 12 ft in this area, due to the local winds and a component of longer period NW swell. NW swell in excess of 8 ft covers most of the area north of 06N and west of 115W. Models suggest that a second and stronger cold front will approach the northwest section of the area tonight, and move eastward across the waters north of 20N through early next week. The main impact will be a new round of NW swell, with combined seas in excess of of 12 ft to as high as 20 ft propagating across most of the region north of 12N and west of 120W Sun through late Mon. During the early to middle part of next week, the leading edge of this next round of northwest swell will mix with shorter period northeast and east swell emerging from the gap wind areas, and possibly even southerly swell, to create an area of mixed seas south of 12N between 95W and 110W. $$ Ramos