000 AXPZ20 KNHC 300338 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Nov 30 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 Tehuantepec Gale Warning: Northerly winds have gradually increased across the Gulf of Tehuantepec this afternoon, and are assumed to be reaching gale force this evening, as moderate N winds are well established across the western Gulf of Mexico. Winds across Tehuantepec are expected to increase to 30-40 kt 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 09N101W Thu night. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N73.5W TO 08.5N93W TO 07.5N108W, where it transitions to ITCZ and continues on to 08.5N116W TO 09N132W to beyond 08N140W. Scattered moderate to strong convection is from 05N to 10.5N between 76W and 84W, and from 07N to 10N between 92.5W and 106W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure is centered over the Pacific waters W of Central California and extends a ridge axis SE across the area to near 21N114W. The associated pressure gradient is producing gentle to moderate NW winds across the Pacific waters W of Baja California, as broad troffing has developed across the much of the northern peninsula. NW swell moving through the waters is leading to combined seas of 5 to 9 ft across the waters offshore of the peninsula, and 4 to 7 ft across the waters between Cabo San Lucas and Acapulco. This swell will continue to propagate SE, with the peak moving through the southern waters this evening and tonight. 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 early Thu through Fri, raising to 9-13 ft across the northern waters Thu night. See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warning. 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 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 currently producing seas of 8 to 15 ft across the waters W of 120W will continue to propagate across the region, with the leading edge of 8 ft seas currently reaching from the southern Baja California peninsula to 00N140W, and will reach NW of a line from 16N111W to 00N135W to 00N140W Thu. A re-enforcing pulse of NW swell currently moving through the far NW waters will spread SE and into the central waters late tonight through Thu. High pressure N of the region will shift slightly SW and settle near 32N136W by late Thu and act to enhance a broad zone of NE to E winds across the tradewind belt W of 130W through Fri. 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. $$ Stripling