000 AXPZ20 KNHC 101547 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1336 UTC Tue Dec 10 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... The next gale force gap wind event is expected to commence across the Gulf of Tehuantepec Wed morning and continue until around midday Thu, as a strong cold front crosses the Gulf of Mexico. Winds over Tehuantepec will abruptly increase to gale force during the morning and are forecasted to peak between 40 and 45 kt Wed afternoon or evening. Expect peak seas Wed evening between 16 and 17 ft downstream of the Gulf. Strong winds Thu evening will gradually taper to fresh by Sat morning as nocturnal drainage flow maintains strong winds over the near shore waters. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08.5N74W to 06N95W to 08N106W to 07.5N125W. The ITCZ continues from 07.5N125W to beyond 09N140W. Scattered moderate and isolated strong convection is noted from 05N to 07N between E of 84W...from 08N to 10N between 100W and 105W and from 06N to 12N W of 108W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh NW to N winds prevail across most of the offshore waters of Baja California this morning. A 1026 mb high pressure center located near 31N126W will generally remain in place through Thu afternoon, then weaken Fri and Fri night. Offshore seas are currently running 7 to 8 ft in mixed NW swell. Expect winds and seas to diminish slightly today and tonight before a new round of NW swell moves into the region Wed night and Thu. Inside the Gulf of California, fresh to locally strong NW winds will prevail across central and south portions of the Gulf through Wed morning before diminishing slightly Wed and Thu. Peak seas of around 6 ft are expected across central sections during this time. Looking ahead, strong high pressure behind a new cold front moving across southern California will build across the region this weekend, bringing strong NW winds to the waters N of 28N by Sat night and a significant NW swell into the area starting Fri afternoon. This event could persist into early next week. Elsewhere across the Mexican offshore waters, overnight scatterometer data showed NW to W winds around 10 kt from Cabo Corrientes to Puerto Angel, becoming light and variable well offshore. The high pressure currently building across the Baja offshore waters will only build very weakly across the waters south of Cabo Corrientes today and maintain NW to N winds of 10 to 15 kt across most of the remaining Mexican waters through Wed. Light and variable winds across the Gulf of Tehuantepec will prevail today and tonight before the strong cold front crosses the western Gulf of Mexico. Winds across Tehuantepec will quickly blast offshore beginning around sunrise Wed, then quickly increase to gales. See the special section above for more details on this upcoming gale event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE to E winds will pulse to strong over the Gulf of Papagayo tonight and Wed night. The longest lived winds are expected Wed night through Thu with seas peaking around 8 ft. Elsewhere, gentle to moderate S to SW monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador through Sat night. REMAINDER OF THE AREA... A 1026 mb high pressure center located near 31N126W is slowly building SSE into the subtropics. Overnight scatterometer data generally showed NE to E tradewinds of 15 to 20 kt across the waters S of 24N and W of 115W. This high pressure will shift slightly S through Tue night and promote a freshening trade wind flow across the region from 22N to the ITCZ and W of 110W. NW swell propagating across the Baja offshore waters will also move into this area overnight to produce seas of 8 to 10 ft. The NW swell will continue to gradually decay through tonight. However, increasing trade winds on the S side of the building high will compensate and keep seas around 8 ft in this area through mid week. A frontal boundary remains stalled over the NW corner of the discussion area near 30N140W. A much stronger frontal system to the NW of this front will also approach this same area and stall Thu. Large NW swell will move out ahead of this next front and propagate into the regional waters beginning early Wed, and cause seas in this area to build through Fri. Seas will eventually peak between 12 and 14 ft Thu night and Fri morning in the far NW portions of the area. This swell will combine with wind waves generated by the fresh to strong trade winds S of 20N Wed night through Thu night. A surface trough propagating W will further tighten the pressure gradient in this area and cause seas to build to between 10 and 14 ft from 10N to 20N W of 130W Fri night and Sat. $$ CAM