000 AXPZ20 KNHC 190911 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0911 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong to near gale force northerly winds will pulse across the gulf waters and as far S as 13.5N96W through Tue afternoon. Stronger drainage flow on Tue evening will result in minimal gale force conditions developing and continuing through mid morning on Wed. Model guidance hints at minimal gale force again Wed night and yet again Thu night, but support is not currently as pronounced as the Tue night event. Ashfall Advisory: The Fuego Volcano at 14.5N 90.9W over S Guatemala is erupting. A plume of volcanic ash may reach to the surface through this evening N of 13.5N and E of 93.5W. Low level visibilities may be reduced to 1 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 from 08N78W to 07N95W to 07N102W. The intertropical convergence zone axis extends from 07N102W to 09N117W, then is interrupted by a pair of surface troughs to the W and a surface low near 09N134W. Scattered moderate and isolated strong convection is from 04N to 08N between 78W and 81W, from 05N to 08N between 100W and 104W, within 210 nm S of the axis between 112W and 117W, within 90 nm N of the axis between 112W and 119W, and also from 08N to 10.5N to the W of 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on a developing gale in the Gulf of Tehuantepec, and on an Ashfall Advisory near the coast of Guatemala N of 13.5N which may impact the far eastern Gulf of Tehuantepec zone this evening. Gulf of California: Moderate NW flow will become light by early Tue through Wed as the pressure gradient relaxes. A decaying cold front will move across the area Thu and Thu night, with winds becoming moderate to fresh out of the NW behind it for the end of the week. A 1018 mb surface high is meandering near 26N119W with a ridge extending across the Mexican offshore waters W of 97W. Gentle to locally moderate anticyclonic flow is forecast around the meandering ridge through the middle of the week, ahead of a weak cold front. The front will shift E across the waters N of 28N on Tue through Wed, accompanied by a light and variable wind shift. High pressure will build in behind the front, which combined with inverted troughing E of the Baja Peninsula will support moderate to fresh NW flow W of the peninsula under a tight pressure gradient. Long-period NW swell, in the form of 7 to 9 ft seas, will arrive at 30N120W late Thu night, and reach the northern coast of the Baja Peninsula early Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section above for more details on the gale warning in the Gulf of Papagayo, and on an Ashfall Advisory near the coast of Guatemala N of 13.5N. Gulf of Papagayo: Fresh to locally strong NE winds, with seas building briefly to 8 ft are expected to pulse through the week, diminishing to moderate to fresh Fri night. 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 through the week. REMAINDER OF THE AREA... A 1011 mb surface low is analyzed at 09N134W, while a pair of surface troughs are to the E. The eastern trough, which is the remnant of a weak low, extends from 08N119W to 14N119W, while the western trough extends from 07N126W to 13N125W to 17N120W. Scattered moderate and isolated strong convection associated with the low is from 06N to 11N between 129W and 133W. The low and troughs will continue W accompanied by fresh E winds and seas to 8 ft through early Wed. A cold front extends from 1008 mb low pressure just N of the area near 33N133W through 30N129W to 23N133W to 21N140W. Recent scatterometer data showed fresh to strong southerly winds N of 28N just ahead of the front. A secondary front is dropping S into the area to the E of 140W. Reinforcing NW swell of 8 to 10 ft accompanies the secondary front. The associated NW swell will subside to less than 8 ft by early Tue. Yet another cold front or trough is forecast to breach 30N140W by Tue afternoon with a new set of NW swell in its wake. Seas will build to 8 to 12 ft, highest along and N of 30N. A ridge will set up from 29N140W to 18N106W on Wed night with strong NE trades, and seas of 8 to 11 ft forecast from roughly 10N to 22N W of 125W on Thu, with the NW swell commingling and pushing eastward through the end of the week. $$ Lewitsky