000 AXPZ20 KNHC 211128 AAA TWDEP Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 1128 UTC Wed Dec 21 2022 Updated Remainder of Area section 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 1115 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure ridging is building southward along the eastern slopes of the Sierra Madre Mountains as a central Gulf of Mexico low pressure system shifts eastward. As this happens, the gradient in southeastern Mexico is tightening as cold dense air surges southward toward the Gulf of Tehuantepec gap region. The resultant surge of northerly winds out over Tehuantepec is bringing gale-force winds to 35 kt. These conditions are expected to last through this afternoon. Seas are forecast to build to a range of 9-13 ft with these winds. Northerly winds will then gradually diminish by early Thu. Seas will subside to below 8 ft by early Thu morning. Please read the latest High Seas Forecast issued by the the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Gale Warning in NW Part of area: A complex low pressure system west of the area has an associated cold front that is along 143W. The low and associated front will shift northeastward through Thu, remaining NW of the forecast area. However, southerly winds to the east of the cold front are reach strong to near gale-force speeds, with a small area of gale force winds expected in a just a few hours north of 24N and west of 137W. An overnight ASCAT pass from 0658Z depicted a large swath of southerly 20-30 kt winds in this area. Seas of 11-18 ft in W to NW swell are expected within the area of gale-force winds. The gale-force winds are expected to diminish to strong to near gale this afternoon. These winds will shift north of the discussion area by early on Thu. Seas in the area will subside to below 12 ft by Thu afternoon. Please read the latest High Seas Forecast issued by the the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from low pressure in northwest Colombia near 11N75W southwestward to 07N79W and northwestward to 10N85W, then to 07N91W and to 06N100W. The ITCZ extends from 06N100W to 07N110W to 08N118W to 06N128W and to beyond 09N140W. Scattered moderate convection is within 120 nm north of the ITCZ between 126W-139W, also within 60 nm north of the trough between 91W-95W and within 30 nm south of the trough between 91W-92W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information about an ongoing gale event in the Gulf of Tehuantepec that is expected to last through this afternoon. High pressure ridging is Updated Remainder of Area sectionpresent over the western portion of the Baja California offshore waters. Moderate N to NE winds are across the Baja California offshore waters. Fresh to strong NW to NNW winds are occurring in the Gulf of California south of 30N with 4-6 ft seas, while moderate to fresh winds prevail in the northern Gulf with 2-4 ft seas. Gentle or weaker winds and 3-5 ft seas prevail elsewhere. For the forecast, gale force northerly winds in the Gulf of Tehuantepec will continue through this afternoon before diminishing by early this evening. Fresh to strong NW winds in the Gulf of California will diminish tonight. Fresh NW winds develop Sat and Sat night mainly in the central southern sections of the Gulf. Looking ahead, a more significant Tehuantepec gap wind event is expected Fri through the weekend. Gales could last from Fri afternoon through Sun night, with storm force winds possible on Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh northeast to east winds are in the Gulf of Papagayo region, while moderate to fresh east winds extend offshore of Papagayo southwestward to 90W. Seas are 5-6 ft over these waters. Light to gentle winds prevail elsewhere north of the monsoon trough off of Guatemala and El Salvador, with seas to 4 ft. Gentle S-SW winds and seas of 3-5 ft due to long-period S to SW swell are present to the south of the monsoon trough. For the forecast, fresh to strong northeast to east winds will continue to pulse in the Papagayo region through the rest of the forecast period. The strongest winds are mainly expected at night and into the mornings, when seas are expected to build to 6 to 7 ft. Gentle to occasionally moderate winds will continue elsewhere through the remainder of the week and the upcoming weekend. Seas will build to 8 ft today well offshore western Guatemala due to swell from a Gulf of Tehuantepec gap wind event. A larger swell can be expected there Fri night through the weekend due to a stronger Gulf of Tehuantepec gap wind event. REMAINDER OF THE AREA...Updated Please read the special features section above for details on a gale warning in the NW corner of the forecast area, from 27N to 30N between 137W and 140W. A cold front is well west of the area along 143W. Latest overnight ASCAT data depicts strong SSE winds north of about 24N and west of 137W, although strong winds likely extend as far south as 22N there. Seas of 8-12 ft are likely occurring with these strong winds. A ship observation from 0700Z this morning reported S winds of 30 kt near the location of 25N140W. Scattered showers and isolated thunderstorms are noted along and near 140W N of 19N. Elsewhere, high pressure ridging prevails over the area between 115W and 135W from 20N to 30N. Light to moderate anticyclonic winds and 3-6 ft seas continue over this area. Fresh trade winds are present from the ITCZ from 20N and west of 118W with 5-8 ft seas. For the forecast, moderate to fresh trade winds S of 20N and W of 120W are expected to change little through Thu. The low pressure and cold front described above in the special features section will shift northeastward through this evening at which time fresh to strong S-SW winds are expected to be confined to N of 27N and between 135W-140W along with seas of 8-12 ft between 135W-137W, and higher seas of 12-16 ft between 137W-140W. Conditions are expected to shift N of 30N by early on Thu. NW swell generated from the low pressure system W of the area will propagate southeastward merging with an existing area of swell that is between 122W-135W from 07N to 13N by early on Thu. The leading edge of the entire swell area is expected to reach near 130W and S to 06N at that time, with resultant seas in the range of 8-11 ft. The swell area is forecast to gradually expand eastward to near 121W by Fri. $$ Aguirre