000 AXPZ20 KNHC 030900 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 900 UTC Sun Dec 3 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 0848 UTC. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 06N95W to 1010 mb low pressure near 08N114W. The intertropical convergence zone reaches from 08N114W to 10N130W to 10N140W. Scattered moderate convection is from 07N to 13N between 105W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Higher pressure north of the area continue to support fresh to strong gap winds through the Gulf of Tehuantepec. Associated seas including shorter period swell generated from the strong gap winds reach 200 to 300 nm downstream of the Gulf of Tehuantepec, mixed with longer period NW swell. The high pressure weakens through tonight, allowing winds to diminish below 20 kt and seas to subside below 8 ft by late Mon, with minor pulse to 25 kt again Mon night due to local drainage flow. Strong gap winds return by Tue night, possibly increasing to gale force by late Wed due as a cold front pushes across the western Gulf of Mexico and through southern Mexico. Looking ahead, strong high pressure builds north of the area behind the front, supporting a persistent strong gale event across the Gulf of Tehuantepec through late in the week. Elsewhere off the Pacific coast of Mexico, weak high pressure is maintaining gentle to moderate breezes across the region. Long period 8 to 10 ft swell is propagating across all open waters, except within 150 nm of the coast south of Los Cabos. The swell will gradually decay below 8 ft in all offshore waters by Tue. For the Gulf of California, strong high pressure will build well north of the area, over the Great Basin and northern Rockies early next week. This will support strong NW winds over the northern Gulf of California by early Mon, spreading into the central Gulf Mon night and early Tue, and the southern Gulf Tue night into Wed with seas to 9 ft. Winds may reach near gale force over the northern Gulf late Tue, with strong easterly gap winds penetrating across areas in Baja California Norte into the Bay of San Sebastian. The winds will diminish slightly Wed, but increase again late in the week as reinforcing high pressure builds north of the region. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A recent scatterometer satellite pass indicated fresh to strong offshore gap winds across the Papagayo region. These winds may diminish slightly today, but will increase again to 25 kt during tonight. Seas downstream from the Gulf will build to 6-8 ft during the time of peak winds, subsiding slightly each afternoon and evening. Elsewhere, light to gentle N to NE winds are expected north of the monsoon trough and mainly moderate S to SW winds are expected to the south of the monsoon trough. Seas are in the 4-6 ft, but are expected to build to 5-7 ft in a SW swell to the south of the monsoon trough beginning on this afternoon and into Monday. REMAINDER OF THE AREA... A recent scatterometer indicated fresh to strong winds on the northern semicircle of 1010 mb low pressure centered near 08N114W along the western terminus of the monsoon trough. Seas are near 12 ft in the area of strong winds, mixed with longer period NW swell, encompassing the entire portion of the discussion area west of 100W. The convergence of these winds is supporting showers and a few thunderstorms, from 07N to 13N between 105W and 120W. A dissipating cold front is moving east of 140W associated with 1011 mb low pressure centered just west of 140W near 29N141W. Gale force winds are noted north of this low pressure, but outside the area of this discussion. The low pressure will remain west of the area as it drifts south to southwest through late today and weakens, keeping associated winds and seas west of the area. A mid to upper level disturbance is supporting a trough near along 135W/136W from 15N to 20N. The gradient between the trough and high pressure to the north of the area will result in fresh to strong easterly winds from 20N and 30N between 130W- 140W with seas building to 8-11 ft through early next week as the trough slowly moves westward. $$ Christensen