000 AXPZ20 KNHC 010934 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Dec 1 2022 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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: High pressure building across the eastern slopes of the Sierra Madre mountains in Mexico tonight behind a cold front will push southward overnight, and support the next Gulf of Tehuantepec gap wind event. Strong northerly winds will begin across the Tehuantepec region during the next several hours, and increase to gale force from early Thu through Fri morning. Seas will build to 9-13 ft during this time. Strong to just below gale force winds are then expected to continue Fri and Fri night, extending offshore to 12N, before winds increase again to gale force Sat through Sun evening as the high pressure strengthens again across the western Gulf of Mexico. Winds are then expected to gradually diminish Mon and Mon night. Please see the latest High Seas Forecast at http://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Of note, the 20-year climatology of the Tehuantepec gap wind events indicates that on average 16 gale-force events and 5 storm-events occur in the Gulf of Tehuantepec per cold season. Most gale-force events occurred during November and December, while most storm-force winds occurred in January. Pacific Gale Warning: A strong cold front across the open NE Pacific is sinking southward to along 34N early this morning, between 130W and 150W. 1037 mb high pressure NW of the front is creating a strong pressure gradient immediately to the north of the front, and producing gale force winds between the front and about 37W. These conditions will weaken slightly this morning as the front sinks southward into the far NW waters of the discussion area, and will cross 30N140W late this morning. Gale force NE winds to 35 kt are expected behind the front to the W of 135W as it sinks slowly into the northwestern waters through this afternoon. Seas will build to 15-18 ft behind the front in mixed NE wind sea and strong N swell. Gale conditions are expected to end by late afternoon as the front moves slowly southward and the pressure gradient continues to relax. Please see the latest High Seas Forecast at http://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N75W to 07N90W to low pressure near 12.5N115W 1011 mb to 10N120W. The ITCZ continues from 10N120W to beyond 08.5N140W. Scattered moderate isolated strong convection is noted from 05N to 12N between 81W and 101W, from 11N to 17.5N between 100W and 116W, and from 07.5N to 11.5N W 122W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate NW winds prevail across the offshore waters of Baja California to Cabo Corrientes early this morning. Seas are generally 4 to 6 ft in NW swell. Light winds and seas 3 ft or less prevail inside the Gulf of California. Elsewhere across the remaining Mexican offshore waters, mainly light to gentle winds and seas of 4 to 5 ft are noted. Strong NW to N winds continue to gradually expand in areal coverage across the western half of the Gulf of Tehuantepec, where peak winds are 30 kt and seas to 8 ft. For the forecast, the Tehuantepec gap wind event has just begin tonight. Please, see the Special Features section for more details. Gale force winds are expected to return to the Tehuantepec area Sat through Sun night as the high pressure strengthens again across the western Gulf of Mexico. Winds are then expected to gradually diminish Mon and Mon night. A cold front is expected to reach the Baja California Norte waters Sat, then stall and weaken quickly. Accompanying large NW swell will reach the Baja Norte waters Fri evening, with seas building to 8-10 ft N of Punta Eugenia Fri night, before beginning to slowly fade late Sat. High pressure will build across the Baja region Sun night through Mon and freshen the winds across the Baja waters. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE winds across the Papagayo region have increased to strong in recent hours, and extend downwind to near 91W. Peak seas are estimated at 8 ft. Light to gentle variable winds prevail elsewhere N of the monsoon trough along 07N, with seas of 4 to 5 ft while moderate S to SW winds and 5 to 6 ft seas are seen to the S of the trough. Gentle to moderate S to SW winds prevail off the Ecuador offshore waters to the Galapagos Islands with seas 4 to 5 ft. Active showers and thunderstorms are seen within 60 nm either side of the monsoon trough from SE Costa Rica westward to beyond 95W, and are also occurring beyond 120 nm of the coast of Guatemala. For the forecast, fresh gap winds over the Papagayo region will persist into the upcoming weekend, pulsing to strong each night through Sat night. These winds will extend beyond 92W tonight through Fri, then retract to E of 90W Sat afternoon through Sun. Elsewhere, little change in the marine conditions is expected. Mainly gentle to moderate winds will prevail across the offshore waters of Central America, Colombia, and Ecuador. Seas will subside modestly during the upcoming weekend except in the Papagayo region. NW swell generated from a significant Tehuantepec gap wind event will move across the offshore waters of Guatemala and El Salvador early Fri through Mon. REMAINDER OF THE AREA... A 1018 mb high pressure is centered across the northern forecast waters near 28N122W, and extends a ridge south and southeastward that covers roughly the waters N of 15N between 110W and 140W. Gentle to moderate NE to E winds and seas of 6 to 7 ft are dominating the area N of the monsoon trough/ITCZ to 20N and W of 120W. Moderate to locally fresh SE to S winds winds and seas of 6 to 8 ft are noted S of the monsoon to the equator and W of 120W. A low pressure is forecast to persist along the monsoon trough between 114W and 118W over the next 48 hours and help to focus active weather there. The low will move westward between 120W and 125W by Sat. An area of 6-8 ft seas will move in tandem with the low center. A cold front is approaching the far NW waters early this morning. A pre frontal trough has entered those waters, from 30N137W to 27N140W. Fresh to locally strong S to SW winds are occurring E of the trough N of 27N and W of 131W. Seas have built 7 to 9 ft there in fresh NW swell. Scattered moderate convection is within 120 nm SE of the trough. The cold front will sink southward into these far NW waters this morning, with NE gale force winds and large N swell behind it. See the special features section above for more details. For the forecast, the pre-frontal trough will move slowly SE across the NW waters into Thu, preceded by fresh to locally strong SW winds shifting ahead of it. A strong cold front will follow the trough, and will reach the NW waters after sunrise, and slowly sink SSE across the area waters. Gale force NE winds are expected behind the front W of 135W through late afternoon before gradually diminishing to around 30 kt. Strong to near gale force NE winds and large seas of 12-18 ft are expected behind the front through early Fri morning. Teh front is expected to reach from near 30N128W to 26N140W Fri morning, then begin to stall and weaken quickly. Large N swell generated behind the front will outrun the front Fri, and cross 20N Sat morning. A reinforcing cold front will weaken along 30N Sun. High pressure behind that front will strengthen winds to fresh to locally strong across much of the area N of the ITCZ and W of 115W on Mon. $$ Stripling