000 AXPZ20 KNHC 100905 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Nov 10 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 0900 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. High pressure behind a cold front in the western Gulf of Mexico and cooler air in eastern Mexico has tightened the pressure gradient already in place across the Isthmus of Tehuantepec, and warm sea surface temperatures present in Gulf of Tehuantepec are enhancing gusty winds. ASCAT at 0400 UTC showed 30-35 kt winds in this area. Gale force winds are expected to diminish only slightly through Saturday, and max seas will remain 12-15 ft. Model guidance suggests that this event will last through early next week, with winds increasing again to 35-40 kt Sunday night through Monday night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends across the tropical Pacific from 09N84W to low pressure near 10N128W 1010 mb to 09N140W. Scattered moderate convection is within 30 nm S and 90 nm N of the trough axis between 105W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for information on the ongoing Gulf of Tehuantepec gale warning. A ridge will dominate the waters W of Baja California the next several days, while a trough will meander along the coast of NW Mexico and into the Gulf of California. Moderate NW flow will prevail across the waters W of Baja California today, increasing to fresh tonight as the pressure gradient increases. Long period NW swell associated with a dissipated cold front with seas to 9 ft will propagate southeastward across the waters N of 23N west of Baja California today, then slowly decay and spread southward Saturday. The pressure gradient W of Baja California will significantly tighten early next week, allowing strong NW winds to develop N of 25N with seas building to 8-9 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Nocturnal drainage flow will support pulsing moderate to fresh winds during the overnight hours for the next several days, with seas occasionally building to 5 or 6 ft downstream of the Gulf near 11N87W. Light variable winds and seas of 4-6 ft are expected elsewhere north of 09N, while moderate to locally fresh southerly winds and seas of 5-7 ft are forecast S of 09N the next several days. REMAINDER OF THE AREA... Long period NW swell associated with a dissipated cold front are found NW of a line from 30N120W to 20N140W, with seas currently 8 to 12 ft. The swell will propagate southeastward through the area, with seas 8 ft or greater covering the waters N of 15N W of 115W by tonight, then to near 8 ft throughout the waters by Sunday evening. A weak low pressure of 1010 mb remains along the monsoon trough near 10N128W, and will continue to move westward this weekend. Model guidance indicates a tightening pressure gradient between the low and and stronger pressure to the north into early next week. This may allow the trades to increase to fresh to strong across the waters S of 20N and north of the convergence zone, supporting fresh seas around 8-10 ft. $$ Mundell