000 AXPZ20 KNHC 130356 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Nov 13 2021 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 0000 UTC surface analysis and satellite imagery through 0350 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure that will build in behind a Gulf of Mexico reinforcing cold front and lower pressure S of Mexico will result in the development of a gale-force gap wind event over the Gulf of Tehuantepec beginning Sat morning. Model guidance indicates that peak winds will be near 40 kt Sat night, with seas to near 12 ft. Currently, N winds of 25-30 kt across the Gulf of Tehuantepec reach to 14N. Swell generated by this event will propagate downstream of the Gulf of Tehuantepec, with seas 8 ft or greater reaching as far S as 10N and W to near 103W on Sun. Winds are forecast to drop below gale-force Sun into Mon, then increase back up to gale-force at similar speeds Mon evening. 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 axis extends from 08N83W to 07N100W. The ITCZ begins near 07N100W and continues along 08N113W to 10N128W then resumes W of a low near 09N132W to beyond 10N140W. A 1010 mb low is centered near 10N130W. Scattered moderate convection associated with the low is from 07N to 16N between 123W and 134W. Scattered moderate convection is elsewhere from 06N to 12N W of 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO...Corrected Please see the Special Features section above for details on an upcoming Gulf of Tehuantepec gale event. A weak pressure gradient across the region is supporting light to gentle variable winds along the Baja peninsula and SW Mexican offshore waters. Northwest swell is generating seas in the 5-6 ft range W of the Baja California peninsula, while mixed SW and NW swell supports seas of 4-5 ft across the southern and southwestern offshore waters. Otherwise, moderate to fresh northerly winds are funneling along the Gulf of California being supported by a tighter pressure gradient between the ridge to the west and a surface trough along western Mexico. Seas are 3-4 ft in the Gulf of California. The earlier moderate winds offshore of Baja California have diminished to gentle speeds this afternoon as high pressure north of the area weakens. Moderate to fresh north winds inside the Gulf of California will diminish to gentle to moderate speeds this evening. Strong to near gale-force north winds in the Gulf of Tehuantepec region are expected to reach gale-force Sat morning 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 with seas in the 4-6 ft range in southwest swell. These winds will persist through the forecast period. REMAINDER OF THE AREA... A strong center of high pressure remains north of the area with a ridge extending south to 19N and west of about 124W. The resultant pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ that also includes a 1009 mb low, remnants of Terry near 11N130W, is supporting moderate to fresh northeast to east winds north of the ITCZ to 26N and west of 125W. Satellite imagery shows scattered moderate to isolated strong convection to the east of the 1009 mb low from 08N to 13N between 125W-130W. Scattered moderate convection is within 30 nm of 14N126W. A tight gradient between the low and the aforementioned ridge is leading to fresh to strong northeast to east winds north of the low to near 14N and between 127W-129W. This low is forecast to move in a general westward motion over the next 24 hours while it weakens, eventually to a trough over the far western part of the area by early Sun. Gentle to moderate winds prevail south of the ITCZ. 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 gradient between the aforementioned high pressure ridge and the low pressure of 1009 mb near 11N130W will maintain generally fresh trades south of about 24N and west of 127W through Sat afternoon before decreasing in coverage through late Sun as the surface trough mentioned above reaches the far western part of the area. The area of fresh to strong northeast to east winds north of the low will continue through Sat, then diminish to mainly fresh winds late Sat night or early on Sun. This will allow for seas to subside to 8 ft in the tropical waters west of about 138W. $$ Ramos