000 AXPZ20 KNHC 280307 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 226 UTC Wed Nov 28 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... Gale Warning: A gale warning remains in effect for the Gulf of Tehuantepec. The pressure gradient between strong high pressure in eastern Mexico and lower pressure south of Tehuantepec is supporting 30 to 40 kt northerly winds, as was clearly exhibited from an earlier scatterometer satellite pass. Earlier visible satellite imagery depicted a large arc cloud feature located about 400 nm SSW of the Gulf while emanating well away from it. It denotes the onset of the strong to gale force northerly winds. An earlier altimeter satellite pass indicated seas to 14 ft across the Gulf of Tehuantepec, with the leading edge of 8 ft seas reaching up to 300 nm SSW of the Gulf. The gale force winds are forecast to continue through early Wed, then rapidly diminish through Wed night across the region as high pressure over eastern Mexico quickly moves eastward and weakens. Seas in the Gulf region will subside to less than 8 ft late Wed night. Elsewhere, a 1008 mb low pressure area is embedded along the monsoon trough near 13N106W. Scattered moderate convection is within 300 nm of the center in the northeast quadrant. Environmental conditions are forecast to become conducive for some gradual development and there is a medium chance a tropical depression could form during the next couple days as the low drifts toward the coasts of the Mexican states of Guerrero and Michoacan. Refer to the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOEP/ABNT20 KNHC for more information on this system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N83W to 07N95W to the low pressure near 13N106W to 06N125W. The intertropical convergence zone continues form 06N125W to 07N140W. Scattered moderate convection is observed from 05N to 09N between 115W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Moderate northerly winds across the north and central Gulf of California will diminish through Wed, with seas of 3 to 5 ft. Winds are expected to increase to 20 to 25 kt with seas of 5 to 7 ft across the northern Gulf Thu night and Fri as a cold front sweeps across the area. Long period northwest swell of 8 to 11 ft is reaching the waters near Guadalupe Island, and will reach the coast of Baja California Norte through tonight. The swell will reach the southern coast of Baja California Sur and the Revillagigedo Islands by late Wed. The swell will reach as far east as 105W by late Thu between Clarion Island and Cabo Corrientes, mixing with southerly swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh northeast winds will pulse across the Gulf each night through Sat. Elsewhere, the monsoon trough will exist between 08N and 11N during the rest of the week, with gentle to moderate winds on either side of the trough, with 5 to 7 ft seas expected. REMAINDER OF THE AREA... See Special Features Section above for the latest information on a low pressure system with potential for tropical development. The pressure gradient between a 1022 mb high centered near 27N132W and lower pressure near the ITCZ is resulting in fresh northeast winds over the waters from 09N to 15N west of 135W. This area of trades will diminish through early Wed as the high pressure weakens. Meanwhile long period northwest swell in excess of 8 ft will dominate most of the region west of 120W through late Wed, reaching as high 14 ft near 30N. The swell will continue to move eastward through Sat, with the leading edge of 8 ft reaching 95W by early Sat, mixed with southerly swell. The swell west of 125W will have decayed below 8 ft by that time. $$ Christensen