000 AXPZ20 KNHC 170308 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0315 UTC Fri 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 10N105W to 10N124W where it transitions to the intertropical convergence zone, and extends farther west to beyond 08N140W. Scattered moderate convection was noted within 90 nm S of the monsoon trough between 112W and 120W, and 120 to 150 nm S of ITCZ axis between 128W and 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak 1014 mb stationary surface high centered near 27N123W is forecast to dissipate within 24 hours. This system will be reinforced by a stronger high pressure from the N on Sat. Under this weather pattern, expect gentle to moderate northerly winds across the offshore waters W of Baja California through Fri, with moderate to fresh NW to N flow, and building seas of 6-7 ft N of 25N Sat morning through Sun morning. Gulf of Tehuantepec: Pulses of strong to near gale force northerly drainage flow, with seas building to a max of 11 ft, are forecast overnight into early Fri and again late Fri night into early Sat morning, diminishing afterward as the high pressure over the eastern slopes of the Sierra Madre mountains weakens. Looking ahead, another strong cold front will enter the Gulf of Mexico late Sat, followed by strong high pressure building into northeast and central Mexico through Sun. This will support a return of strong gap winds in the Gulf of Tehuantepec by early Sun, reaching minimal gale force Sun morning through Mon morning. Seas will build to a max of 15-16 ft downstream of the gulf waters near 14N96W late Sun night. Gulf of California: A gentle NW breeze is forecast today becoming light and variable winds tonight and Fri. Strong high pressure building north of the area over the Great Basin will support fresh to strong NW winds across the northern Gulf of California by mid-day Sat, spreading into the central and southern portions of the gulf late Sat into Sun, before diminishing late Sun. Seas are forecast to build to 7 or 8 ft across the central gulf early on Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate N-NE drainage winds are forecast during the overnight hours through Sat night with seas building to 5 ft downstream near 10N87W. Fresh drainage winds are expected on Sun and Mon nights. Light and variable winds, and 3 to 5 ft seas, are forecast elsewhere to the N of 09N, while moderate to locally fresh southerly winds, and 4 to 7 ft seas, are expected S of 09N through the upcoming weekend. REMAINDER OF THE AREA... A 1011 mb surface low is centered near 30N133W with a cold front extending SW to 22N140W. ASCAT passes from 1830 and 1928 UTC indicated fresh to strong NW to N winds within 120 NM in the W semicircle of the low. A combination of altimeter passes and NWP generated wave heights suggested 8 to 10 ft seas in the wake of the front. The low is forecast to move eastward and weaken significantly near 29N127W by late Fri, with the frontal trough extending from the low to near 22N131W. Strong SE to S return flow will develop across the NW waters N of 27N W of 138W by Sat evening, in advance of the next cold front forecast to approach the far NW corner of the areas Sun night. The front will move slowly with the strong S to SW flow persisting over the NW waters on Mon. Gentle to moderate trade winds and 4 to 6 ft seas will persist farther S through the weekend. $$ Cobb