195 AXPZ20 KNHC 061510 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Jan 6 2021 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 FEATURES... Gulf of Tehuantepec Gale Warning: High pressure building into southern Mexico behind a cold front in the western Gulf of Mexico is expected to induce strong northerly gap winds Thu afternoon, which will reach gale-force Thu night, then continue through early Sat. Seas downwind of the Gulf of Tehuantepec will rapidly increase to greater than 10 ft by early Fri, then remain 10-12 ft through Sat. Winds and seas will diminish Sat night and Sun as the cold front moves east and the pressure gradient across southern Mexico weakens. Please read the latest NWS High Seas Forecast issued by 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 extends from northern Colombia near 10N75W to low pressure near 08N86W to 07N113W. The ITCZ continues from 07N113W to 06N120W to 07N140W. Scattered moderate and isolated strong convection is noted from 05N to 10N between 113W and 140W. Scattered moderate convection is noted from 04N to 06N between 84W and 87W, and from 08N to 13N between 101W and 106W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Earlier scatterometer data showed 15-20 kt N to NW winds west of the Baja California peninsula. Moderate to fresh NW to N winds are expected across the offshore waters of Baja California and north of Cabo San Lazaro over the next several days as a ridge remains in place. Large NW swell, with seas in the 10-14 ft range, dominates the waters west of Baja California. Episodes of large NW swell will continue to propagate across the same region through Sun. Gulf of California: Gentle to moderate NW to N winds are expected across the Gulf of California through Sat. Winds are forecast to increase Sat night and Sun as a high pressure settles over the Great Basin region of the United States. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong NE-E winds will pulse in the Gulf of Papagayo this morning and then again by the end of the week through the weekend. Elsewhere, light to gentle winds will prevail north of the monsoon trough while gentle to moderate S-SW winds are expected south of the trough axis. Long period NW swell will continue to spread across offshore waters, with seas less than 8 ft. Large seas generated by gale- force winds in the Tehuantepec region will reach the offshore waters of Guatemala and El Salvador Fri and Sat. REMAINDER OF THE AREA... Broad high pressure prevails across the waters north of 10N west of 110W. A ridge of high pressure is analyzed from 1025 mb high pressure near 31N126W to another 1025 mb high near 29N132W to 26N140W. The ridge axis also extends southeastward to near Cabo San Lucas, Mexico. The gradient between this area of high pressure and lower pressures in the vicinity of the ITCZ is supporting moderate to fresh trade winds from north of the ITCZ to 22N west of 117W. Seas are 9-13 ft range in a mix of primary NW swell and E-NE wind waves. These marine conditions will persist during the next 48 to 72 hours. Long period NW swell continues to propagate across most of the forecast waters north of the equator and west of 100W, with sea heights of 8-12 ft south of 18N, and larger swell of 11 to 16 ft north of 18N. Another surge of NW swell is arriving in the NW part of the forecast area. Looking ahead, the another set of large long period NW swell is forecast to reach 30N140W by Thu night, with seas up to 16-18 ft. A similar set of NW swell is possible by Sat night. $$ Lewitsky