000 AXPZ20 KNHC 082131 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1948 UTC Sun Dec 8 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pres 1011 mb near 09N75W to 06N80W to 07N98W. The ITCZ continues from 07N98W to 08N125W to beyond 06N140W. Scattered moderate convection is from 05N to 11N between 82W and 85W. Scattered moderate to isolated strong convection is from 05N to 11N between 122W and 136W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient over the Isthmus of Tehuantepec has decreased and allowed winds over the Gulf of Tehuantepec to subside to 10 ft. Winds will subside to below 8 ft as the pressure gradient continues to weaken and winds diminish to light and variable by Mon evening. An area of residual 8 ft seas expected to be just SW of the Gulf of Tehuantepec this evening will drift W and merge with a larger area of 8 ft seas S of Cabo Corrientes near 10N by Mon evening. Looking ahead, another gale force gap wind event is expected to affect the Gulf of Tehuantepec Wed through Thu as a stronger cold front crosses the Gulf of Mexico. Winds over Tehuantepec could reach 45 kt during this next event. Elsewhere, gentle winds prevail across most of the offshore waters, as weak high pressure resides over the waters W of Baja to around 121W. Recent scatterometer winds showed variable mainly N to NW winds at less than 10 kt across most of the offshore waters N of 20N. Seas in this area are building in NW swell to 5-8 ft and are expected to reach 6-9 ft this afternoon before subsiding very slowly through Tue. Inside the Gulf of California, recent scatterometer data showed NW winds 10-15 kt south of the Tiburon Basin, with seas 2-5 ft. Winds and seas are expected to diminish modestly through Mon afternoon or evening before high pressure begins to build into the region, and freshen winds across both the Gulf of California and the offshore waters of Baja. Elsewhere across the Mexican offshore waters, variable and gentle winds prevail from Cabo Corrientes to Puerto Angel. Strong N to NE gap winds linger over the Gulf of Tehuantepec, but will continue to gradually diminish to less than 20 kt by Mon morning. Please see the Special Features section above for more details on the Gulf of Tehuantepec Gale Warning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... NE to E winds less than 15 kt generally prevail across the offshore waters N of 10N and W of the Papagayo region. Strong NE to E winds around 20 kt will pulse to around 25 kt each night across and downstream of the Gulf of Papagayo through Thu, with seas peaking between 8 and 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... The latest GOES-16 satellite imagery shows scattered moderate convection within 30 nm either side of a line from 28N134W to 25N138W in association with a mid to upper-level trough extending from 32N133W to beyond 24N140W. Weak high pressure ridging resides over the waters N of 20N. The weak pressure gradient on the S side of this ridge is mainly supporting light to moderate trades N of the ITCZ. This area of high pressure will build during the next several days and cause the trades from the ITCZ to 20N W of 120W to become strong by Thu evening. Large NW swell continues to propagate SE across the region, with seas of 9 to 11 ft dominate the waters N of 10N and W of 120W. This NW swell will continue propagating SE through Mon and gradually decay to around 8 ft to the S of 16N by Mon night. Looking ahead, another cold front will approach the NW portion of the discussion area Mon and introduce new NW swell into the NW waters through the middle of next week. $$ Formosa