000 AXPZ20 KNHC 140907 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Dec 14 2020 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehunatepec Gale Warning: High pressure building southward along the eastern slopes of the Sierra Madre Oriental and across the western Gulf of Mexico behind a cold front will support brief gales in the Tehuantepec region today. Northerly winds at 20-25 kt late this morning will rapidly increase to 30-40 kt by this evening, with seas building up to 12 ft. Minimal gale conditions will persist tonight, then winds will quickly diminish well below gale-force by early Tue morning. Looking ahead, another gap wind event is expected in the Tehuantepec area late Wed through Fri as another cold front moves across the Gulf of Mexico. Marine guidance suggests minimal gale-force winds and building seas of up to 11-12 ft with this latter event. Please, read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from a 1009 mb low pressure over northern Colombia near 10N74W to 05N80W to 06N95W to 06N107W. The ITCZ continues from 06N107W to 08N123W to beyond 07N140W. Scattered moderate isolated strong convection is noted from 02N to 04N E of 80W to the coast of Colombia, from 06N to 08N between 91W and 94W, from 08N to 11N between 125W and 130W. Similar convection can be found from 10N to 15N between 110W and 121W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning remains in effect for the Tehuantepec region. Please, see the Special Features section for more details. A ridge dominates the offshore forecast waters of Baja California. The pressure gradient between the ridge and a meandering trough over the Gulf of Baja California/NW Mexico supports fresh to locally strong N-NE winds from 24N to 28N between 113W and 117W based on recent satellite-derived wind data. These winds are forecast to diminish early this morning, then increase again to 20-25 kt across the waters N of 28N E of 120W by this evening as the pressure gradient tighten again across the offshore waters of northern Baja California. A new set of long period NW swell will reach the waters N of Punta Eugenia today building seas up to 12-13 ft tonight into Tue morning. This swell event will propagate across the waters N of Cabo San Lazaro by this evening. Gulf of California: High pressure over the Great Basin region of U.S. continues to support fresh to strong winds across the Gulf of California, with seas to 8 ft across the south-central waters. A recent scatterometer pass confirmed the presence of these winds forecast to diminish to 20 kt or less late this morning as high pressure weakens. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate to fresh NE-E winds will prevail in the Papagayo region over the next several days with seas of 4-6 ft. Winds are expected to increase to fresh to strong on Fri as high pressure builds over the western Caribbean. Gentle to moderate northerly winds are expected in the Gulf of Panama with sea heights of 3-5 ft. Elsewhere, gentle to moderate winds will prevail S of the monsoon trough with mainly gentle winds N of it. Seas of 5-8 ft in SW swell between Ecuador and the Galapagos Islands will gradually subside to 4-6 ft by tonight. REMAINDER OF THE AREA... High pressure of 1029 mb located near 35N133W extends a ridge SE across the northern forecast waters to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ is supporting a large area of fresh to locally strong trade winds from 12N to 18N W of 120W These winds winds will persist over the next 48 hours as high pressure remains in place. A new set of long period NW swell is propagating over the NW corner of the forecast area. This swell event will continue to spread SE, covering most of the area N of 10N W of 115W by this evening. Seas are forecast to build to 8-13 ft, with the highest seas N of 28N between 117W and 125W. Additional pulses of NW swell will reach 30N140W on Tue. $$ GR