000 AXPZ20 KNHC 070311 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0310 UTC Sat Dec 7 2019 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front that extends across the NW Gulf of Mexico will continue moving SE through Sat, and high pressure will build over eastern Mexico behind the front. The enhanced north-south pressure gradient will support gale force gap winds over the Gulf of Tehuantepec from late tonight through Sat night. Seas will peak between 12-14 ft downstream of the Gulf on Sat night, then subside on Sun as the pressure gradient weakens and wind speeds diminish to fresh to strong speeds. Looking ahead, another gale force gap wind event could affect the Gulf of Tehuantepec Wed into Thu as a stronger cold front crosses the Gulf of Mexico. See latest NWS High Seas Forecast issued by National Hurricane Center under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N78W to 06N104W to 08N115W. The ITCZ continues from 08N115W to 10N130W to beyond 09N140W. Scattered moderate convection is noted within 120 nm of the monsoon trough between 82W and 97W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for more details on the Gulf of Tehuantepec Gale Warning. Fresh to locally strong NW winds continue over the central and southern Gulf of California between a low pressure trough over western Mexico and a weak high pressure ridge over the Baja California offshore waters. These winds will persist through Sat, then diminish to moderate speeds on Sun. Elsewhere, gentle winds prevail across most of the offshore waters, except for increasing northerly gap winds over the Gulf of Tehuantepec. Large NW swell will enter the Baja California Norte waters Sat, with offshore seas building to 8-11 ft by Sat night. This swell will continue spreading SE across the region Sat night through Sun night, then decay Mon into Mon night. A high pressure ridge will build across the northern waters Sun night into Mon, which will result in fresh northerly winds offshore and over the Gulf of California through early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The latest GOES-16 satellite imagery and available lightning data reveals scattered moderate convection continues along the monsoon trough off the coast of Panama and Costa Rica. Strong NE to E winds will pulse across and downstream of the Gulf of Papagayo through Wed, with seas peaking between 8-9 ft downstream of the Gulf each morning. Elsewhere, gentle to moderate S to SW monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador during the next several days. REMAINDER OF THE AREA... Deep low pressure well north of the area is pushing a cold front across the NW waters. The front extends from 30N127W to 27N130W to 23N140W. Earlier scatterometer data revealed the strong winds associated with this system remain north of 30N, with moderate to fresh winds noted from 28N to 30N behind the front. Associated large NW swell is spreading across the region, as seas greater than 12 ft dominate west and northwest of the front. Earlier altimeter data showed seas peaking around 20 ft along 30N. This front will continue slowly moving eastward across the northern waters tonight, then stall and weaken west of 120W Sat into Sat night. Large NW swell will continue propagating SE through the weekend. Seas will remain greater than 12 ft over the northern waters through Sat, then subside Sat night through Sun. Looking ahead, another cold front will approach the NW portion of the discussion area on Mon, introducing another set of NW swell into the NW waters through the middle of next week. $$ Reinhart