000 AXPZ20 KNHC 110306 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 137 UTC Wed Dec 11 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... A cold front over the western Gulf of Mexico will move across southern Mexico tonight, allowing gap winds to gale force to push into the Gulf of Tehuantepec Wed morning and continue into Thu morning, with winds peaking to near 40 kt and seas to 17 ft. 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 07N78W to 09N112W to 1010 mb low pressure near 08N115W to 08N125W. The intertropical convergence zone continues from 08N125W to beyond 07N140W. Scattered moderate and isolated strong convection is noted from 08N to 10N between 110W and 115W, and from 08N to 10N between 135W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 1026 mb high pressure centered near 31N125W is maintaining gentle to moderate northerly flow off the coast of Baja California, depicted well in an earlier scatterometer pass. The scatterometer pass also indicated moderate to gentle winds through the Gulf of California except for south of 25N where fresh N to NE winds were noted. A couple of ship observations corroborated this off Los Cabos as well. A concurrent altimeter pass showed seas of 6 to 8 ft between Baja California Sur and the Revillagigedo Islands, mainly in NW swell. This will diminish through mid week, but seas will build by late Fri as a new round of NW swell moves into the area off Baja California Sur. Elsewhere off southern Mexico outside of the Gulf of Tehuantepec, gentle to moderate flow will persist through mid week. Building high pressure west of the area will allow increasing winds later in the week, especially off Cabo Corrientes. 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 31N125W is supporting fresh to locally strong tradewinds across the waters south of 25N and west of 115W. Recent altimeter data showed seas of up to 9 ft in the area of fresh trades, and this may increase slightly through mid week as the trade winds persist. A frontal boundary remains stalled north of the discussion area near 30N140W. A much strong frontal system to the northwest 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 northwest 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. $$ Christensen