000 AXPZ20 KNHC 192150 CCA TWDEP Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 1605 UTC Thu Nov 19 2020 Corrected Special Features section 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 1545 UTC. ...SPECIAL FEATURES...Corrected Recently downgraded Tropical Depression Polo is centered near 17.1N 120.3W at 19/1500 UTC moving W at 10 kt. The estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Satellite imagery shows that Polo is a sheared tropical cyclone, with its low-level center clearly exposed. The overall cyclonic circulation of Polo consists of broken to overcast low and mid-level clouds with possible embedded scattered showers. Only occasional bursts of small clusters of scattered moderate convection are noted within 240 nm of the center in the E semicircle. Polo is forecast to maintain its present motion through Fri. Additional weakening is forecast, and Polo is expected to become a remnant low later today. The remnant low is then forecast to dissipate by Fri night. Please read the latest High Seas Forecast issued by the National Hurricane Center at website- https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Tropical Storm Polo NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gulf of Tehuantepec Gale Warning: The gradient between strong high pressure over southern Mexico and low pressure in the Pacific is supporting gale force northerly winds across the Tehuantepec region. A 12Z observation from ship with call ID "OYGH2" at position near 14N96W indicated northeast winds of 41 kt. This long-lived gale event is expected to last through early Sun. Wave heights will build to a maximum of about 20 ft downstream of the Gulf of Tehuantepec near 14N96W today. The leading edge of 8 ft or greater sea from associated swell is forecast to reach as far west as 110W by late Fri. 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 axis extends from southern Costa Rica to the remnant low of tropical cyclone Iota near 12N92W, then to 09N100W to 09N110W to 14N118W to 10N130W, where overnight scatterometer data indicates that it transitions to the ITCZ to beyond the area at 08N140W. Scattered moderate within 30 nm of the trough between 112W-114W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning remains in effect for the Gulf of Tehuantepec. Please see the Special Features section above for details. A ridge extends across the offshore forecast waters west of Baja California, producing gentle to moderate northwesterly winds. Wave heights are 5-7 ft in long-period northwest swell. Little change in winds and sea heights is expected through Mon. A weakening cold front extends from southeastern California southwestward to 29N122W, where it transitions to a weakening stationary front well to the west of Baja California. The cold front will gradually dissipate through Fri as it moves across northern Baja California and the northern Gulf of California. As this happens, strong high pressure will build south-southeastward over the offshore waters through the weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate southwest winds are south of the monsoon trough east of 100W, with gentle west to northwest winds north of the trough. Wave heights are generally 5-7 ft, except 7-9 ft in mixed swell between 88W and 100W. Large wave heights generated in the Tehuantepec region will propagate into the offshore waters of Guatemala and El Salvador through early Fri before subsiding. REMAINDER OF THE AREA... See the Special Features section above for details on Tropical Depression Polo. A cold front extends from southeastern California southwestward to 29N122W, where it transitions to a weakening stationary front to 26N130W and to near 23N140W. The stationary front will continue to weaken through today and dissipate by late tonight, while the cold front will gradually dissipate through Fri as it moves well east of the area. A set of long-period northwest swell behind the front will shift eastward through Fri and gradually decay. A weak 1012 mb low pressure currently near 33N143W has an attendant cold front that extends to the southwest well to the west of the discussion area. The low will further weaken as it moves to near 33N137W by early Fri, with the cold front just moving into the far northwest part of the area. The front will then become stationary and weaken into Fri, before degenerating to a trough later on Fri. This low pressure system and front will usher in large northwest swell into the northwest part of the area on Fri, with wave heights of 8-9 ft and up to 10 or 11 ft just north of that part of the area. Strong high pressure will build south-southeastward across the area through the weekend. This will act to nudge the trough westward on Sat. The pressure gradient between the high pressure and the remnant low of Polo should allow for wave heights in the range of 7-10 ft to exist west of about 125W and from 14N to 22N through Sat. By late Sat night into Sun, a rather large area of fresh to strong trades is forecast by the global models to develop over a good portion of the western half of the area as the gradient associated to the aforementioned strong high pressure tightens. Wave heights with these winds are expected to reach the range of 8-10 ft as an existing northwest swell component, as mentioned earlier, helps to boost wave growth there. $$ Aguirre