000 AXPZ20 KNHC 290907 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 821 UTC Wed Nov 29 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Nocturnal drainage effects are expected to increase winds to near 30 kt by sunrise this morning. Winds are then expected to increase very slowly during the day, and reach gale force just before sunset, as moderate northerly wind flow becomes established across the western Gulf of Mexico. Northerly winds of 30-40 kt are expected across Tehuantepec tonight through Thu morning before diminishing to 25-35 kt throughout the day. Gale force winds to 35 kt are expected Thu night, with minimal gales expected to linger Fri morning through Sat morning, pulsing back again to gale Sat night. During this extended gale event, seas are forecast to peak at 12-14 ft early Thu morning, with downstream seas of 8 ft and higher reaching as far as 08N103W Thu night. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N75W to 09N90W to 07N105W, where it transitions to the ITCZ and continues on to 08N120W to beyond 09N140W. Widely scattered moderate convection is from 07N to 10N between 78W and 101W, and from 11N to 16N between 108W and 112W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warning. High pressure is centered over the Pacific waters W of Southern California with a ridge axis that extends into the area to near 20N110W, and is producing moderate to locally fresh NW winds across the Pacific waters W of Baja California. NW swell moving through the waters is leading to combined seas of 8 to 11 ft across the waters N of Cabo San Lazaro, and 6 to 9 ft southward to the waters SW of Cabo San Lucas. This swell will continue to propagate SE, with seas 8 ft and higher reaching the Revillagigedo Islands by late this afternoon. Seas across the waters W of Baja California to the Revillagigedo Islands will remain above 8 ft through late this week, as another reinforcing pulse of NW swell propagates into these waters tonight through Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A modest pressure gradient between high pressure over the western Gulf of Mexico and lower pressure across the southwest Caribbean is producing fresh to strong offshore gap winds across the Papagayo region. These winds will be enhanced with overnight drainage effects for the next few days, peaking near 25 kt during the late night through late morning hours. Seas downstream will build to 6 to 8 ft during the peak winds, with the winds and seas diminishing slightly each late afternoon through evening. Light to gentle N to NE winds, and 4 to 5 ft seas are expected elsewhere through Sat N of the monsoon trough. Moderate southerly winds, and 4 to 6 ft seas, are forecast south of the monsoon trough. Northerly swell generated in the Gulf of Tehuantepec will reach the western part of forecast zone PMZ111 (offshore waters of Guatemala and El Salvador) Thu through the end of the week. REMAINDER OF THE AREA... A large area of NW swell producing seas of 8 to 12 ft will continue to propagate across the region with the leading edge of 8 ft seas currently reaching from the central Baja California peninsula to 06N140W this morning, and will reach NW of a line from 20N110W to 09N116W to the equator near 135W tonight. A re- enforcing pulse of NW swell of 12 to 14 ft will reach the NW waters today through Thu, while winds increase to 20 to 25 kt across the waters from about 19N to 24N west of 135W to 140W. Seas of 8 to 12 ft are then expected to cover nearly the entire forecast waters S of 30N W of 110W Fri through the upcoming weekend. $$ Latto