000 AXPZ20 KNHC 131540 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1405 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Again this morning, a ship crossing the Gulf of Tehuantepec, reported gale force winds across this area. Winds are forecast to diminish below gale force early this afternoon as high pressure over east-central Mexico weakens. Strong northerly winds are forecast to persist tonight and Friday night, particularly between 0600-1200 UTC with the assistance of the nocturnal drainage flow. The overall pattern will improve as high pressure north of the area weakens, and 20-25 kt gap winds are anticipated on Saturday. ...TROPICAL WAVE... A tropical wave is relocated along 89W N of 07N based of satellite imagery and moisture products. Some cyclonic turning is noted in the cloud field and along the wave axis near 10N. Isolated to scattered moderate convection is observed from 07N to 13N between 84W and 92W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 08N90W to 12N105W to 10N115W to 14N130W to 09N140W. Outside of the tropical wave... scattered moderate convection is from 09N to 12N between 112W and 122W. Scattered moderate to isolated strong convection is near 10.5N97W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure of 1021 mb located near 31N130W extends a ridge SE to near the Revillagigedo Islands with another ridge stretching SW over the NW waters. This system is supporting moderate to locally fresh northerly winds off the Baja California coast, with seas of 5 to 6 ft. The ridge will slightly weaken on Friday as a cold front approaches the far NW corner of the forecast region, but will continue to dominate the offshore waters of Baja through the upcoming weekend. 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 broad area of low pressure is located near 13N111.5W. This system is producing a concentrated cluster of showers and thunderstorms, within about 210 nm NW quadrant of the low center. However, recent satellite wind data indicate that the system does not have a closed surface wind circulation. The same scatterometer data provide observations of fresh to locally strong winds within about 90 nm N semicircle of low center. Seas are generally 8 to 9 ft E of center based on an earlier altimeter pass. Some slow development of this disturbance is possible during the next several days while it moves generally westward at 15 mph. Another low pressure system is centered near 19N130W with an estimated minimum pressure of 1011 mb. The most recent scatterometer pass indicates fresh to strong winds within about 300 nm of a fairly well defined low level center. These winds are the result of the pressure gradient between the low and a ridge to the N. The low is currently moving over cooler water. This along with increasing wind shear aloft has limited the associated shower and thunderstorm activity near the low center. Further development is therefore not anticipated, although fresh to strong winds may persist on the northern semicircle of the low center as it continues to move westward over the next couple of days. A new set of long period NW swell with seas up to 12 ft is propagating across the NW waters. This swell event will bring seas of 8 to 12 ft across the waters NW of a line from 30N121W to 18N130W to 13N140W by early Friday morning, and across the forecast region NW of a line from 30N116W to 20N116W to 10N130W to 05N140W by early Saturday morning. The swell, with significant wave heights of 8-12 ft will dominate most of the forecast waters N of 10N W of 110N by Sunday morning. Expect the highest seas over the NW waters. $$ GR