000 AXPZ20 KNHC 112256 AAA TWDEP Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 2256 UTC Thu Nov 11 2021 Updated the Offshore Waters Within 250 nm of Mexico 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 1800 UTC surface analysis and satellite imagery through 2245 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure that will build in behind a Gulf of Mexico cold front and lower pressure south of Mexico will result in the development of a gale-force gap wind event over the Gulf of Tehuantepec beginning early on Sat afternoon, or possibly sooner. Model guidance indicates that peak winds expected with this upcoming gale-force gap wind event will be at about 35 kt late on Sat, with seas to near 12 ft. Swell generated by this event will propagate downstream of the Gulf of Tehuantepec, with seas 8 ft or greater reaching as far south as 10N and west to near 103W on Sun. Present indications are that winds will drop to just below gale-force Sun afternoon into Mon, then increase back up to gale-force at similar speeds lat on Mon. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from Colombia near 06N74W to across northern and central Panama to 09N85W to low pressure near 08N93W 1011 mb and to 06N97W. The ITCZ extends from 06N97W to 06N105W to 07N115W, where latest scatterometer data indicates that it pauses. It then resumes at 09N135W to beyond 09N140W. Scattered moderate to isolated strong convection is seen within 60 nm south of he ITCZ west of 139W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO...Updated Please see the Special Features section above for details on an upcoming Gulf of Tehuantepec gale event. A ridge extends from a strong 1030 mb high pressure center that is well to the northwest of Baja California Norte southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge and a trough over northwest Mexico supports moderate northwest to north winds from the waters of Baja California Norte to offshore of Cabo San Lazaro, while moderate winds remain off Baja California Sur. Mainly fresh northwest winds are also found over most of the Gulf of California, strongest through central portions. Light to gentle winds prevail over the remainder of the open waters off southwestern Mexico. Winds over the Gulf of Tehuantepec have become light and variable along with seas 4-6 ft due to a south to southwest swell. Seas of 6-8 ft due to a northwest continue west of the Baja California peninsula, and 4-6 ft elsewhere over the open waters off Mexico. Seas are in the 3-6 ft range in the Gulf of California. Fresh winds offshore of Baja California will gradually diminish to gentle through Fri afternoon as high pressure north of the area weakens. Fresh north winds inside the Gulf of California will diminish to gentle to moderate by Fri evening. Strong to near gale-force north winds will return to the Gulf of Tehuantepec region late tonight into early Fri. These winds are expected to reach gale- force early Sat afternoon, or possibly sooner as high pressure builds in behind another cold front that is forecast to sweep across the southern Gulf of Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Moderate to fresh gap winds remain across the Papagayo region, with gentle to moderate winds elsewhere north of the monsoon trough. These winds may briefly pulse to strong speeds on Sun. Gentle to moderate south to southwest winds are south of the monsoon trough. Seas of 4-6 ft due to a southwest swell are over the offshore waters. Gentle to moderate south southwest winds will persist south of the monsoon through the forecast period. Winds will weaken across and downwind of Papagayo today but return to moderate to fresh beginning on Fri and into early next week. REMAINDER OF THE AREA... A strong 1030 mb high pressure center is analyzed north of the area near 35N129W. It has a ridge extending west-southwestward to 30N140W and continuing southwestward to well west of 140W. The resultant pressure gradient between the high and lower pressure within the monsoon trough and in the vicinity of the ITCZ is supporting moderate to fresh northeast to east winds north of the ITCZ and monsoon trough to near 23N and west of about 120W, with gentle to moderate winds north of about 25N. Gentle to moderate winds prevail south of the monsoon trough and ITCZ. The remnant lows of Sandra near 12N136W 1011 mb and Terry near 12N125W 1010 mb are accompanied by areas of northeast to east 20-25 kt winds to their north along with higher seas peaking to 12 ft. A trough extends from the low near 12N125W to 09N130W and to the low near 12N136W. Satellite imagery shows scattered moderate to isolated strong convection within 180 nm south of the trough between 123W- 125W, and within 90 nm SE and 120 nm SW quadrants of the low near 12N125W. Scattered moderate convection is seen north of the trough within 60 nm 12N129W. Elsewhere, seas are in the 8-10 ft range due to mixed northeast and northwest swell across the trade wind belt west 120W. Seas in the 6-8 ft range are elsewhere. The aforementioned high pressure ridge will remain across the northern waters maintaining a zone of fresh trades south of about 23N and west of 124W through most of Sat. These trades will gradually decrease in coverage through the weekend as the remnant low of Sandra weakens further to a trough and shifts to west of 140W, and the remnant low of Terry reaches the far western part of the area. As a consequence, seas will subside to 8 ft across the trade wind belt, but confined to west of 135W by Sun. $$ Aguirre