000 AXPZ20 KNHC 060305 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0305 UTC Wed Dec 6 2017 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 0200 UTC. ...SPECIAL FEATURES... Gulf of California: Strong high pressure from the U.S. Great Basin and northern Rockies southward towards the desert SW of the U.S. will support strong NW winds spreading as far S as 25N through Wed. Another area of strong high pressure will build across the region Wed night through Thu and is expected to initiate another round of gales across north and north-central portions Thu. Seas are expected to build to 6 to 9 ft across the basin tonight through Wed, and up to 11 ft over the N Gulf on Thu during the gale. Also, as the strong winds occur across the Gulf, strong northeasterly gap winds will bleed through gaps in the mountain peaks across the northern peninsula and spill across the Bay of San Sebastian. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N78W to 08N95W to 08N104W. The ITCZ extends from 08N104W to 08N113W to 11N125W to beyond 09N140W. A surface trough extends from 17N126W to near the ITCZ at 10N130W. Scattered moderate convection is from 07N to 18N between 120W and 129W. Isolated moderate convection is elsewhere within 120 nm of the ITCZ axis. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Overnight drainage effects will allow winds to pulse to 20 to 25 kt tonight. Winds will then persist from fresh to strong Wed through Fri morning ahead of a cold front moving across the western Gulf of Mexico, arriving in southern Mexico Thu. Winds will further increase to gale force on Fri afternoon as the cold and dry air pushes into the Gulf of Tehuantepec. Seas will build to 15 ft by early Sat, with seas 8 ft or greater reaching as far as 500 nm downstream to the W-SW of the Gulf of Tehuantepec. Looking ahead, strong high pressure building behind the front across central Mexico will support a persistent strong gale over Tehuantepec through the weekend. Elsewhere off the Pacific coast of Mexico, weak high pressure is maintaining gentle to moderate breezes across the region. High pressure building north of area will result in strong gap winds pushing across low lying areas of Baja California Norte and into adjacent waters Thu. A larger plume of strong NE winds will push off the coast of Baja California Sur north of Cabo San Lazaro Thu night and Fri, with seas 8 to 10 ft reaching from near shore to beyond 250 nm offshore. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong winds will pulse through the Gulf of Papagayo into Wed morning. Otherwise, moderate to fresh NE winds across the Papagayo region will persist with seas downstream maintaining a range of 6 to 8 ft. Winds and seas will diminish Thu as strong trade winds across the SW Caribbean Sea diminish and veer SE. Looking ahead, strong high pressure will build N of the region, allowing strong gap winds and building seas to reappear late Sat night into Sun. Winds may even approach minimal gale force Mon. Elsewhere, light to gentle N to NE winds are expected N of the monsoon trough, and mainly gentle to moderate S to SW winds are expected to the S of the monsoon trough. Seas are in the 5 to 7 ft range in SW swell this evening to the S of the monsoon trough, and will subside to 4 to 6 ft through mid week. Large NW swell of 8 to 10 ft from the upcoming Tehuantepec gap wind event will spread across the offshore waters of Guatemala late this week and over the weekend. REMAINDER OF THE AREA... A developing warm front extends from 27N135W to beyond 30N138W, just NE of a dissipated low. The pressure gradient between high pressure N of the front and the lower pressures associated with the front will continue to support fresh to strong SE to S winds N of the front through Wed morning. The front will lift north of the area Wed morning. However at the same time, an approaching front W of the area will support the development of strong southerly winds N of 26N and W of 133W to the south of the departing warm front, with NW swell of 8 to 12 ft lingering N of 21N and W of 132W through Wed night. The front W of the area will then weaken Thu and dissipate just NW of the discussion area early Fri as winds diminish over the area. Although winds will diminish, additional NW swell greater than 8 ft will continue to affect these waters through the end of the week. Looking ahead, strong southerly flow will return late Sat N of 26N W of 135W ahead of yet another cold front approaching from the NW, along with a fresh set of large NW swell. Elsewhere, long period swell to 9 ft persisting across much of the area south of 15N will decay below 8 ft through Fri. A new round of NW swell to 9 ft will propagate into the discussion area, encompassing the region N of 15N W of 130W by Thu night, then most of the area W of 120W by late Fri into Sat, mixing with shorter period NE waves N of 20N and E of 125W. $$ Latto