000 AXPZ20 KNHC 210935 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Dec 21 2023 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure along the eastern slopes of Mexico is enhancing northerly winds funneling through the Chivela Pass, which is supporting gale-force north to northeast winds in the Gulf of Tehuantepec, with seas peaking at around 12 to 13 ft. Gale conditions will continue through this evening. Strong to near-gale force winds will then continue through Fri night before diminishing Sat. Eastern Pacific Significant Swell event: Large NW swell with seas of 12 to 16 ft will continue to impact the waters north of 26N between 122W and 136W through late today. Seas will subside below 12 ft by early Fri morning. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 04N77W to 05N96W. The ITCZ extends from 05N96W to 06N140W. Scattered moderate convection is noted from 04N to 10N between 101W and 122W, and from 04N to 07.5N between 129W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on the ongoing Gulf of Tehuantepec Gale Warning. Winds of 30-35 kt and seas of 8-13 ft are occurring in the region. Aside from the gale in the Gulf of Tehuantepec, a weak pressure gradient prevails across the area. Gentle winds are west of the Baja California peninsula and the open offshore waters. Recent ASCAT satellite data show moderate SW winds over the northern Gulf of California. Large NW swell has reached the waters west of Baja California Norte, where seas are 6 to 10 ft. The swell is being driven by a cold front and low pressure area, which are located a few hundred nm west of Baja California Norte. Seas are 4-6 ft west of Baja California Sur, 3 ft or less over the Gulf of California, and 5-7 ft elsewhere over the open waters off Mexico, except 8-13 ft closer to the Tehuantepec region. For the forecast, a cold front will move into the waters west of Baja California later today ahead of a low pressure that will approach far northern Baja California Norte from the W on Fri bringing fresh west to northwest winds. The large northwest swell will continue to propagate southeastward across the waters west of Baja California Norte today, then spreading across the Baja California Sur offshore waters tonight through Fri night. Another set of NW swell will move into the Baja California Norte waters this weekend. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent ASCAT satellite data shows strong to near-gale force winds are over the Gulf of Papagayo region. Fresh winds likely extend downstream of the Gulf to near 09N92W. Seas of 8-10 ft are over and downstream of the Gulf of Papagayo region. Northwest swell generated by the Gulf of Tehuantepec gale-force gap wind event is supporting seas in the 7-9 ft range over the outer offshore waters of Guatemala and El Salvador. Fresh to strong northerly winds prevail over the Gulf of Panama. These winds likely extend downstream to 05N. Seas are 6 to 8 ft in the area. Gentle to moderate winds and seas of 5-7 ft are elsewhere south of the monsoon trough. For the forecast, strong to near-gale force NE winds will continue over the Gulf of Papagayo through tonight. Then, fresh to strong winds will prevail through early Sat morning, and diminishing on Sat. NW swell generated by the Gulf of Tehuantepec gale-force gap wind event will continue to impact the outer Guatemala and El Salvador offshore waters through tonight. Fresh to strong north winds will continue over the Gulf of Panama through tonight before diminishing to moderate Fri. Elsewhere, winds are expected to be moderate or weaker for the next several days. ...REMAINDER OF THE AREA... Please see the Special Features section above for details on a significant swell event currently affecting the northern portion of the basin. A cold front extends from 30N120.5W to 25N128W, with a dissipating cold front continuing from that point to 22N137W. To the N of 28N between 125W and 135W, fresh to strong NW winds and seas of 13 to 16 ft in NW to N swell prevail. Elsewhere NW of the front, seas are 9 to 14 ft. Fresh trades prevail north of the ITCZ to 18N and west of 130W, where seas are 7 to 10 ft. Moderate trades prevail north of the ITCZ to 18N and east of 130W with seas 6 to 8 ft, except 9 to 10 ft from 05N to 11N between 91W and 105W. Moderate winds prevail south of the ITCZ. Seas of 8-9 ft in NW to N swell are south of 10N between 105W and 120W. Seas of 5-8 ft are elsewhere over the discussion waters. For the forecast, low pressure will approach 30N from the north this morning. This will support fresh to strong winds over the waters N of 27N and E of 135W through Fri. The low is already spreading a large set of NW swell over the area, discussed in the special features section above. Seas greater than 8 ft associated with this swell will propagate across the area through the end of the week and into the weekend, mainly NW of a line from Baja California Sur to 06N140W. Areal coverage of seas greater than 8 ft will start to decrease by Sun as the seas gradually subside. $$ Hagen