000 AXPZ20 KNHC 111531 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1259 UTC Mon Nov 11 2019 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: A cold front will enter the NW Gulf of Mexico tonight, and reach the SW Gulf of Mexico Tue. Strong high pressure will build across the eastern slopes of the Sierra Madre mountains in Mexico behind the cold front, and help usher in the next gale force gap wind event in the Gulf of Tehuantepec on Tue. Strong to minimal gale force winds will begin to funnel through the Chivela Pass into the Gulf by Tue afternoon, then winds are expected to peak near 45 kt in the Gulf of Tehuantepec by Tue night, with seas building to near 20 ft during this time. The area of high pressure will shift eastward into the SE United States Wed. This will loosen the pressure gradient over the Tehuantepec region, and winds will diminish below gale force Wed night. Marine guidance suggests another gale force gap wind event across the Tehuantepec region on Fri. See the latest NWS High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... The axis of a tropical wave is adjusted near 96W from 03N to 14N based on Tropical Wave Diagnostics. Convection is limited near the wave axis at this moment. The axis of a tropical wave is near 122W from 04N to 16N, moving W at around 10 kt. Scattered moderate isolated strong convection is from 11N to 14.5N between 114W and 121W, and from 07N to 11N between 121W and 127W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N77W to 07N96W to 11N115W to 09N127W to 10N133W to 08N140W. Scattered moderate isolated strong convection is from 06N to 09N between 80W and 90W. Similar convection is also noted within about 120 nm south of the monsoon trough between 102W and 112W, and from 09N to 12N W of 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to strong northerly winds prevail in the Tehuantepec region this morning. These winds will briefly diminish to 20 kt or less this afternoon before pulsing to strong once again late tonight into early Tue morning. The next Gulf of Tehuantepec gale force gap wind event is expected to begin by Tue afternoon. Please see the Special Feature section above for more details. Elsewhere, a ridge dominates the offshore forecast waters west of Baja California, supporting gentle to moderate northerly winds, and seas generally under 6 ft. Little change is expected through Tue. Strong high pressure building across Mexico will tighten the pressure gradient over N and central Mexico today into Tue, and will result in fresh to strong NW to N winds near the entrance of the Gulf of California late this morning. The fresh to strong winds will spread south across the waters between Cabo Corriente and Los Cabos later today and tonight, and farther south to near 17N between 105W and 110W by late Tue before diminishing to 20 kt or less by Tue night. Seas are forecast to build to 8 or 9 ft over this area. Over the Gulf of California, light to gentle winds will prevail most of the forecast period, with the exception of moderate NW to N winds over the southern part of the Gulf today. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Mainly fresh NE-E winds will prevail across the Gulf of Papagayo through Wed. Farther south, mainly gentle to moderate S-SW monsoonal flow will continue across the offshore forecast waters of Costa Rica, Panama, Colombia, and Ecuador through the middle of the week. Seas will remain in the 4-7 ft range. Seas generated by the strong gale force gap wind event in the Gulf of Tehuantepec will propagate across the offshore waters of Guatemala and El Salvador on Wed, with seas likely building to 10 to 14 ft in northerly swell. REMAINDER OF THE AREA... A surface ridge extends from 1024 mb high pressure near 35N131W to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ is supporting mainly moderate to fresh NE trades N of the ITCZ to about 20N and west of 120W, with seas of 7 to 9 ft. These seas will gradually subside below 8 ft by Tue night into Wed. A cold front will reach the far NW waters tonight, and extend from 30N137W to 27N140W by Tue morning, and from 30N136W to 26N140W on Tue night. Seas of 8 to 9 ft in NW swell can be expected W of the front. A larger set of long period NW swell, with periods of 20 seconds, is forecast to enter the NW waters on Thu. Seas associated to this swell event will peak near 13 or 14 ft over the far NW waters by Thu night. Looking ahead, a low pressure system is expected to form during the next few days several hundred miles south or south-southwest of the southern tip of the Baja California peninsula. Some gradual development will be possible thereafter while the system moves slowly northward. Currently, scattered moderate convection is noted from 07N to 10N between 103W and 106W. The latest Tropical Weather Outlook gives this system a low chance of tropical cyclone formation through 5 days. $$ GR