000 AXPZ20 KNHC 180949 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Nov 17 2017 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 0945 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Pulses of strong northerly drainage flow will diminish to 20 kt or less around sunrise this morning, with winds becoming light and variable this afternoon. Strong to near gale force conditions will resume late tonight in the wake of a cold front in the Gulf of Mexico, and then quickly increase to gale force on Sun morning, and continue through through sunrise on Mon morning, with seas building to a max of 16 ft downstream of the gulf waters near 14N95.5W on Sun night. Winds will diminish to 20 kt or less around sunrise on Tue. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the coast of Costa Rica at 09N84W to 10N92W, then dips SW to 09N105W where scatterometer winds indicate a transition to an ITCZ which continues W-NW to beyond 11N140W. Scattered moderate convection is noted within 60 nm of 08N95W and within 180 nm of 10N114W. Scattered moderate isolated strong convection is noted within 150 nm 13N125W, and within 90 nm either side of a line from 08N132W to 11N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph for Gulf of Tehuantepec Gale Warning. A NW to SE orientated ridge just beyond 250 nm seaward will maintain moderate to locally fresh NW flow W of the Baja Peninsula through sunrise on Sun when the pressure gradient will relax, supporting moderate NW flow through sunrise on Mon. Light N winds winds then expected through sunrise on Thu. Gulf of California: Light and variable winds at sunrise this morning will quickly become northerly this morning with strong N winds developing across the gulf waters N of 30N by early this afternoon. These strong NW winds will shift S across the central gulf waters tonight surrounded by fresh NW flow elsewhere. Little change then expected through Sun morning when the pressure gradient will relax with moderate NW flow forecast across the entire gulf waters by sunrise on Mon, becoming light northerly flow Mon night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh NE drainage winds are forecast during the overnight hours through the middle of next week with seas building to 5 ft downstream near 10N87W. Light and variable winds, and 3 to 5 ft seas, are expected elsewhere to the N of 09N, while moderate to locally fresh southerly winds, and 4 to 7 ft seas, are forecast S of 09N through the middle of next week. REMAINDER OF THE AREA... A pair of 1017 mb surface lows are weakening over the NW waters and should dissipate tonight as a NE to SW aligned ridge builds from 32N124W to beyond 20N140W. Fresh to locally strong southerly flow will develop across the waters N of 26N W of 134W tonight, with seas building to 9 ft. Expect strong southerly winds N of the ridge, generally across the waters N of 23N W of 137W on Sun through Tue, with seas building 8 to 12 ft. The associated cold front will arrive at 32N140W late Wed, with seas building 12 to 18 ft W of the front through Thu. Moderate to locally fresh anticyclonic flow expected across the tropics N of the ITCZ and W of 120W through the middle of next week with seas building to 8 ft. $$ Nelson