000 AXPZ20 KNHC 302205 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A 1026 mb high pressure center located over N central Mexico extends a ridge SE to the Tehuantepec region, and is producing a tight pressure gradient there. Gale force northerly winds across the region have diminished to 25 to 35 kt this afternoon, but are expected to increase again tonight to 30-40 kt through early Friday morning. Minimal gale force winds are then expected to continue through Friday night before diminishing to 20-30 kt Saturday morning. During this extended gale event, seas are forecast to peak at 12- 14 ft early Friday, with downstream seas towards the SW of 8 ft and higher reaching as far as 650 nm offshore. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N73.5W TO 11N83W TO 09N88W TO 07N102W, where it transitions to the ITCZ and continues on to 08.5N111W TO 09N131W TO beyond 08N140W. Scattered moderate convection is from 06N to 09N between 77W and 81W, and from 05N to 08N between 83W and 85W. Scattered moderate convection is also from 06N to 10N between 93W and 102W. Scattered moderate to isolated strong convection is from 06N to 09N between 112W and 116W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Ridging extending SE across the region will maintain gentle to moderate breezes across the entire area through early next week. Long period northwest swell propagating across the waters offshore of Baja California is producing seas of 7 to 10 ft except 5 to 7 ft near the coast across Baja California Sur. Reinforcing NW swell currently has moved into the northern waters today, producing combined seas to 13 ft off Baja California Norte. This new pulse of swell will reach as far south as the Revillagigedo Islands at 10 ft swell by early Sat, then decay below 8 ft by late Mon. Please see Special Feature section for detail concerning the gale warning in the Gulf of Tehuantepec. 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) today through the end of the week. REMAINDER OF THE AREA... A large area of NW swell producing seas of 8 to 14 ft across the waters W of 116W will continue to propagate across the region, with the leading edge of 8 ft seas currently reaching from the offshore waters of southern Baja California peninsula to 00N140W, and will reach NW of a line from 18N112W to 00N140W Fri. A re-enforcing pulse of NW swell currently moving through the N waters will spread SE and into the central waters through Fri night. High pressure north of the region will 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 into Sun, and will start to fade below 8 ft through early next week. $$ Stripling