000 AXPZ20 KNHC 200306 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Nov 19 2018 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. .SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Strong to near gale force northerly winds will pulse across the gulf waters and as far S as 12.5N95.5W through late Tue. Stronger drainage flow on Tue evening will result in minimal gale force conditions developing and then continuing through early Wed morning. Max seas are forecast to 12 ft near 15N95.5W on Tue night. The northerly winds are forecast to gradually diminish through Fri morning. Ashfall Advisory: The Fuego Volcano at 14.5N 90.9W over S Guatemala is erupting. Volcanic ash may reach the surface N of 13.5N and E of 94W with local visibilities of 1 to 3 nm. Mariners should exercise caution. If mariners encounter volcanic ash, they are encouraged to report the observation to the National Weather Service by calling 305-229-4425. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends SW off the Pacific coast of Colombia at 07N78W across the southern Gulf of Panama then turns NW to the Pacific coast of Costa Rica at 09N83W, then turns SW again through 06N94W to 08N100W to 06N106W where scatterometer winds indicate a transition to an ITCZ, which then continues NW interrupted by a 1010 mb surface low at 09N137W. Scattered moderate isolated strong convection is noted within within 60 either side of a line from 07N80W to 09N85W, within 30 nm either side of a line from 06.5N94W to 07N98W, within 90 nm either side of a line from 08N101W to 05N109W, within 60 nm of 06.5N117.5W, and from 06N to 11.5N W of 131W. Isolated moderate to strong convection is observed from 08N to 14N between 116W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Feature section for Gulf of Tehuantepec Gale Warning and for an Ashfall Advisory near the coast of Guatemala and across the far eastern Gulf of Tehuantepec. Gulf of California: Light NW flow is forecast across the entire gulf wters through Wed, except light and variable winds are expected over the northern waters on Wed as a weak front passes. A 1018 mb surface high is meandering near 27.5N118W with a ridge extending across the Mexican offshore waters W of 97W with gentle to locally moderate anticyclonic flow forecast around the meandering ridge through early Thu, except a weakening cold front will shift E across the waters N of 28N on Wed accompanied by a light and variable wind shift. The pressure gradient will tighten on Thu with fresh northerly winds developing across the open waters W of 108W with locally strong NW flow N of 28N on Fri night. Additionally, long-period NW swell, in the form of 7 to 9 ft seas, will arrive at 32N120W late Thu, and reach the northern coast of the Baja Peninsula early Fri, with these swells propagating as far S as 23N late Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See Special Feature section for an Ashfall Advisory near the coast of Guatemala. Gulf of Papagayo...Fresh to locally strong NE winds, with seas building briefly to 8 ft well downstream near 10.5N87W, are expected through early Fri. These strong winds will extend as far SW as 09.5N88.5W. Light to locally moderate northerly flow is forecast elsewhere N of the monsoon trough, while moderate southwesterly monsoonal flow, with 4 to 6 ft seas, is forecast S of the monsoon trough this week. REMAINDER OF THE AREA... A 1010 mb surface low is analyzed at 09N137W. This low will continue W accompanied by fresh E wind and seas to 8 ft through early Wed. A cold front extends from 32N122W to 24N128W accompanied by a fresh SW-W-NW wind shift. A secondary front is analyzed as a trough along 32N130W to 25N134W with 7 to 9 ft seas W of trough forecast to subside to less than 8 ft by sunrise. Although the cold front will weaken, it will reach the Baja Peninsula on Wed evening. A tightening pressure gradient will result in strong W winds N of 30N between 125W and 140W on Tue night into Wed. A ridge will set up from 29N140W to 18N106W on Wed night, with strong NE trades, and seas to 11 ft, forecast from 11N to 22N W of 127W on Thu, surrounded by NW swell resulting in 7-9 ft seas across the waters elsewhere N of the ITCZ W of 115W. $$ Nelson