000 AXPZ20 KNHC 241610 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Nov 24 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURE... A gale warning remains in effect for Gulf of Tehuantepec through 1500 UTC. Minimal gale force winds continue cross the Gulf of Tehuantepec and downstream to near 14.5N95.5W with seas of 8 to 12 ft. Winds are expected to diminish below gale force by late morning today, and to 20 kt or less late Sat morning. The NE swell generated by this gap wind event is mixing with long- period cross equatorial SW swell, with seas 8 ft or higher well downstream of the Gulf of Tehuantepec along 09N between 94W and 100W. Expect winds of 20 kt or less and seas of less than 8 ft only briefly on Sat afternoon. Strong N winds are forecast to resume again on Sat night, with gale conditions expected by mid- day Sun. The latest computer model guidance is suggesting another 30 to 40 kt gap wind event on Sun night, with seas building to 16 or 17 ft by early Mon morning. Gale conditions should persist through Mon. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 08N90W to 07N101W. The ITCZ continues from 07N101W to 11N117W to 10N130W to 09N135W to beyond 10N140W. Scattered moderate to strong convection is occurring from 05.5N to 10N E of 85.5W to the coast, and from 07N to 11N between 117W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warning. A weak ridge continues across the offshore waters of Baja California producing mainly light to gentle NW winds and seas of 3 to 4 ft. Seas will begin to build late this morning through this afternoon in NW swell, and peak at 4 to 7 ft at 13 to 15 seconds across the waters W of Baja tonight, then subside some on Sat into Sun. Long-period NW swell in the form of 7 to 9 ft seas will reach 30N120W by early Mon morning, and spread S across the offshore forecast waters W of Baja with 8 to 13 ft seas at 17 to 19 seconds Mon night and Tue. Winds will increase very slightly over the weekend, mainly due to daytime heating. However early on Monday, stronger high pressure will begin to build across the region from the NW and act to increase NW winds to 20-25 kt across the waters N of 26N, including the Sebastian Vizcaino Bay, by the late afternoon and evening hours. Gulf of California: Overnight scatterometer data indicated gentle to locally moderate winds across the entire Gulf. This flow will continue through tonight. The pressure gradient will relax further, with light and variable winds expected through Mon. Strong to near gale force NW flow is expected to develop across the northern Gulf Mon night, with fresh to strong winds spreading southward across the central and southern portions of the Gulf through Tue night. Seas will quickly build to around 8 ft across the northern Gulf by Tue morning and then 6-8 ft through central portions by Tue night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong NE winds are occurring across and downstream of the Gulf of Papagayo this morning, with the assistance of the nocturnal drainage flow. Seas have built to 6- 7 ft downstream of the gulf. Expect a typical nocturnal maximum of around 25 kt across the region through early Mon morning, diminishing to 15-20 kt by mid afternoon. Seas will maximize to around 7 ft each morning near sunrise. Moderate to locally fresh NE winds are expected across the Gulf of Fonseca each night through Mon. Light and variable winds, and 3 to 5 ft seas are expected elsewhere through Sun night to the N of the monsoon trough which has been meandering between 09N and 11N. Moderate southerly winds, and 3 to 6 ft seas, are forecast S of the monsoon trough. REMAINDER OF THE AREA... A stationary front is located just NW of the discussion area near 31N141W. An elongated surface low will develop along the front just W of the area by this evening then move NE of the area tonight with the associated cold front entering the forecast waters. The front is forecast to reach from 30N136W to 22N140W tonight, and extend from 30N129W to 20N139W by Sat night. Fresh to strong southerly winds are expected ahead of the front, but mainly N of 26N. A reinforcing or secondary cold front will reach the far NW corner of the area by Sat morning followed by fresh to strong NW winds and seas up to 10 or 11 ft. The fronts are forecast to merge on Sun as they move eastward and approach 125W. Overnight altimeter data indicated seas of 10 to 14 ft from 20N to 27N W of 134W while seas of 8 ft or greater in long period NW swell are propagating across the waters NW of a line from 30N121W TO 12N137W TO 12N140W. This swell event will begin to subside, with seas 8 ft or greater mainly S of 15N and W of 125W by late Sat. At that time, another pulse of NW swell is expected to reach the far NW waters. $$ Stripling