000 AXPZ20 KNHC 242204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... ...GALE WARNING IN THE GULF OF TEHUANTEPEC... The wind speeds in the Gulf of Tehuantepec just weakened to less than gale-force during the last few hours. Expect N to NE winds of 20 to 30 knots during the rest of the afternoon and evening, until just before sunrise on Saturday. The sea heights will reach 10 feet. Expect wind speeds of 20 knots or less from just before sunrise on Saturday until just before sunrise on Sunday. The wind speeds will increase to N 20 to 25 knots just before sunrise on Sunday. The sea heights will be less than 8 feet until midday on Sunday. Expect Gale-force winds to return to the Gulf of Tehuantepec around midday on Sunday. The sea heights may reach 11 feet, with the arrival of the gale-force winds. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH FROM 09N84W TO 08N95W TO 09N104W. THE ITCZ CONTINUES FROM 07N104W TO 08N120W TO 09N128W TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG FROM 07N TO 09N BETWEEN 79W AND 83W...WITHIN 60 NM OF ITCZ BETWEEN 110W AND 112W...AND WITHIN 60 NM OF ITCZ BETWEEN 123W AND 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 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 cold front is along 140W from 24N to 26N. A 1012 mb low pressure center is near 28N144W. The low center is forecast to move NE during the next 24 hours, and end up well to the north of the discussion area. The cold 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. $$ mt