000 AXPZ20 KNHC 130937 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 937 UTC Thu Oct 13 2016 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 0900 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec early this morning. The gales are a result of a fairly tight surface pressure gradient between high pressure over east central Mexico and lingering lower pressure south of the area in the tropical eastern Pacific. The overall pattern will improve as high pressure north of the area weakens, and 20-25 kt gap winds are anticipated by Friday night. ...TROPICAL WAVE... A tropical wave is along 93W N of 11N, moving toward the Gulf of Tehuantepec, and enhancing scattered convection off the coast of El Salvador. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A segment of the monsoon trough extends from 10N86W to 10N97W. Another segment continuous from 14N103W to 10N114W to 14N130W to 10N140W. Scattered moderate to isolated strong convection is within 90 nm north of the monsoon trough between 87W and 92W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extending from 1022 mb high pressure centered near 31N130W to near the southern tip of the Baja California peninsula, is supporting generally moderate northerly winds off the Baja California coast with 5 to 6 ft seas. These winds will increase to 15 to 20 kt this morning as the ridge builds slightly eastward. The high pressure will weaken later today ahead of a frontal boundary moving into the northeast Pacific, allowing the winds to diminish. Looking ahead, long period northwest swell will push into the waters off Baja California Norte by Friday and Baja California Sur Friday night, with building seas of 8-10 ft by early Saturday morning. Winds to 25 kt with seas to 11 ft are possible off the northern portion of Baja California Norte, that includes forecast zone PMZ009 early next week as well as the ridge builds eastward again. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate southwest winds persist south of the monsoon through...including the waters between Ecuador and the Galapagos Islands. Seas are 4 to 6 ft south of the monsoon trough largely associated with long period southwest swell. These marine conditions will change little over the next few days. REMAINDER OF THE AREA... A large area of strong convection is ongoing in the vicinity 1008 mb low pressure centered near 14N111W. The low pressure itself however remains very disorganized, as noted in a scatterometer pass from 0430 UTC. The main area of circulation remains aloft in the mid levels of the atmosphere, but a more prominent surface circulation may be starting to form within the area of showers and thunderstorms. Winds are generally light to moderate near the center of the low pressure, but may reach 20 kt within 120 nm to the north of the center. Seas are generally 6 to 7 ft. Slow development of the low is possible over the next several days it continues to move west- northwest along the monsoon trough. Another low pressure system is centered near 18N129W with an estimated minimum pressure of 1010 mb. A 06 UTC scatterometer pass indicated fresh to strong winds within 270 nm of a fairly well developed low level center. The low has moved over cooler water in the past couple of days. This along with increase wind shear aloft as resulted in limited shower and thunderstorm activity near the low. Further development is therefore not anticipated, although fresh to strong winds may persist as the low continues westward over the next couple of days. Seas up to 12 ft are possible in the area of strongest winds to the north of the low level center due to the added component of northwest swell starting to enter the area from the north central Pacific. By Friday, the long period swell will bring seas of 8 to 12 ft across the area west of a line from 30N117W to 09N140W. The swell will subside through late Saturday, but seas 8 ft or greater will still reach from the southern tip of the Baja California peninsula to 01N140W. $$ CHRISTENSEN