000 AXPZ20 KNHC 292123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Nov 29 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The next gap wind event over the Gulf of Tehuantepec is expected to commence late tonight into early Mon morning as strong cold front currently moving across the western Gulf of Mexico reaches the Isthmus of Tehuantepec. High pressure building behind the front will provide a tight pressure gradient across the area, and bring an increase in winds funneling into the Gulf of Tehuantepec. Winds will rapidly increase to strong gale force by Mon afternoon and reach 40-45 kt by Mon evening. Seas will peak near 20-21 ft by Mon night. Marine interest transiting across or in the vicinity of the Gulf of Tehunatepec should be aware of this upcoming gap wind event, and take necessary action to avoid these hazardous marine conditions over the affected waters. Winds are forecast to diminish below gale force on Tue night. Please, see the latest 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 a 1009 mb low pressure over northern Colombia near 10N75W to 07N80W to 10N94W to 08N110W to a 1013 mb low pressure near 07N118W to 09N130W. The ITCZ continues from 09N130W to beyond 07N140W. Convection is limited. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning is in effect for the Gulf of Tehuantepec. Please, see Special Feature Section for more details. A ridge prevails across the offshore waters of Baja California, anchored by high pressure of 1026 mb centered near 34N130W. This system is producing gentle to moderate NW-N winds. Seas are in the 5-7 ft range. Long period NW swell will reach the waters N of Punta Eugenia by Tue building seas to 8-10 ft by Tue night. Strong high pressure over the Great Basin of U.S. supports fresh to strong NW winds in the Gulf of California. Sea heights are in the 4-6 ft range. A recent scatterometer pass confirmed the presence of these winds, forecast to persist trough Mon morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E winds are expected in the Gulf of Papagayo Mon night through early Wed morning with seas building to 9 ft. mainly moderate to fresh NE will prevail the remainder of the forecast period. Seas generated by a strong gap wind event in the Gulf of Tehuantepec will propagate across the offshore waters of Guatemala and El Salvador Mon night through Tue night. Elsewhere, moderate S to SW winds are expected S of the monsoon trough with mainly gentle easterly winds N of the monsoon trough. REMAINDER OF THE AREA... A ridge dominates the northern forecast waters and extends SE to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure within the monsoon trough, and in the vicinity of the ITCZ, is supporting moderate to fresh trade winds north of 10N and west of 120W. Seas are generally 6-8 ft across this area. A surface trough is analyzed from 20N128W to 15N131W to 10N128W. An area of moderate to isolated strong convection is on the E side of the trough covering from 12N to 15N between 122W and 128W. Moderate to fresh NE winds are noted per scatterometer data near the northern end of the trough axis forecast to drift westward while weakening. A well defined swirl of low clouds is noted on visible satellite imagery near 07N118, and a surface low pressure of 1013 mb is analyzed in this position along the monsoon trough. Fresh winds are seen within about 60 nm on the E side of the low center. Large NW swell will continue to propagate across the forecast waters. A new set of long period NW swell will reach the NW corner of the forecast region on Mon building seas to 8-10 ft N of 11N and W of a line from 30N117W to 20N120W to 11N127W by Tue afternoon. Another and larger NW swell event will begin to propagate across the NW waters on Wed, with building seas of 12-16 ft W of a line from 30N133W to 20N140W by Wed night. $$ GR