000 AXPZ20 KNHC 262151 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2055 UTC Mon Nov 26 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURE... A Gale Warning is in effect for the Gulf of Tehuantepec. The pressure difference between strong high pressure building southward along the eastern slopes of the Sierra Madre Occidental in Mexico and lower pressure south of Mexico will induce a gap wind event over the Gulf of Tehuantepec this afternoon. North winds of 20 to 30 kt across the Gulf will reaching minimal gale force at or near 21Z. Then, winds will further increase to 40 kt tonight into Tue morning. Winds are expected to diminish below gale force by Wed morning. Expect seas to build to the range of 10 to 14 ft with this gap wind event tonight into early Tue morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1007 mb low over Colombia centered near 08N73W to 10N85W to 08N91W to 11N100W to a 1009 mb low near 10N105W to a 1009 mb low near 09N110W to another 1009 mb low near 09N119W. The ITCZ continues from 09N119W to 07N130W to beyond 08N140W. Numerous moderate isolated strong convection is noted from 06N to 10N W of 135W. Scattered moderate convection is within 120 nm NE semicircle of low located near 09N119W. Scattered moderate isolated strong convection is from 04N to 07N E of 81W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate to fresh northerly winds are expected across the north and central Gulf of California tonight and Tue with seas of 3-5 ft. Light to gentle northwest to north winds along with seas of 5 to 7 in a NW swell are west of the Baja California Peninsula for the time being. Wave model guidance depicts that an extensive set of long-period NW swell associated with a cold front presently well northwest of the discussion area will reach the waters west of Baja California Norte beginning late Tue night into Wed morning and the southern tip of Baja California Sur by late Wed night into Thu. The wave guidance shows seas building to the range of 8 to 12 ft with this upcoming swell event, with the highest of these seas expected north of about 23N W of 115W by early Thu morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Enhanced infrared imagery from GOES-E continues to show intermittent plumes of volcanic ash originating from the Fuego volcano in southern Guatemala. The plumes are tracking in a west-northwest direction and become diffuse as they cross into SW Mexico and near the coast of Chiapas. The volume of ash within these plumes remains light and does not warrant an ashfall advisory at this time. Gulf of Papagayo: Moderate to at times fresh northeast winds will pulse across the Gulf each night through the end of the week. Elsewhere, the monsoon trough will meander between 08N and 10N during the rest of the week, with gentle to moderate northeast winds north of the trough, and gentle to moderate southwest winds to the south of the trough. Seas north and south of the trough will be in the range of 5 to 7 ft in cross-equatorial SW swell through at least Wed. REMAINDER OF THE AREA... An elongated area of low pressure, analyzed along the monsoon trough near 10N105W is producing disorganized shower and thunderstorm activity. Environmental conditions are expected to become conducive for some gradual development and a tropical depression could form during the next few days. The disturbance is currently moving slowly westward but is forecast to turn northwestward by Tuesday, and then could turn northward or north- northeastward later this week. Showers and thunderstorms remain poorly organized in association with another area of low pressure located near 09N119W or about 1200 miles south-southwest of the southern tip of the Baja California peninsula. Strong upper-level winds are expected to prevent significant development of this system during the next couple of days while it remains nearly stationary. The pressure gradient between a 1026 mb high center analyzed near 30N130W and lower pressure near the ITCZ supports an area of fresh to strong NE winds over the waters from 09N to 16N W of 130W, and from 09N to 13N between 120W and 130W. Altimeter data continue to show seas of 8 to 10 ft in this region. This area of trades will shrink westward, and mainly W of 130W over the next 24 hours. Large-long period NW swell associated with a strong cold front located about 400 nm to the northwest of the discussion area will propagate southeastward through the northern and central waters through Wed, with seas rapidly building to the range of 12 to 18 ft NW of a line from 30N128W to 16N140W by early Tue afternoon. The leading edge of the 8 ft seas is expected to reach the Revillagigedo Islands near 106W by early on Thu. $$ GR