000 AXPZ20 KNHC 150234 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Mar 15 2019 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... ...Developing Gulf of Tehuantepec Gale Warning... A cold front moving across the northwest Gulf of Mexico this evening will reach the western Bay of Campeche Friday afternoon and evening, and allow northerly winds to blast through the Chivela Pass Friday evening and night. Winds across the Gulf of Tehuantepec will increase to around 30 kt overnight Friday, and then briefly to gale force early Sat morning, before diminishing slightly by late Sat morning to around 30 kt. Gale force winds to near 40 kt will then increase across the Tehuantepec region Sat evening and night then diminish to near 30 kt Sunday evening. Seas will quickly build with the first pulse of strong north winds, reaching 10-11 ft by Saturday morning. The resultant north to northeast swell will propagate downstream and well away from the Gulf of Tehuantepec through late Sun. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from Costa Rica near 10N85W TO NEAR 06N96W. The ITCZ continues from 06N96W to 03N121W to beyond 04.5N140W. Scattered moderate isolated strong convection is seen from 05.5N to 07.5N between 87W and 96W. Scattered strong convection is within 150 nm of the ITCZ between 119W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Strong high pressure has built across the Great Basin today, with the associated pressure gradient supporting fresh to strong northwest winds across northern and central portions of the Gulf of California, while fresh northwesterly winds prevail elsewhere across the Gulf. These strong NW winds will spread southward across most of the Gulf through tonight, with peak winds near 30 kt expected across central portions overnight. Seas are expected to build to 6 to 9 ft tonight through Fri morning, particularly S of 27N. Winds will diminish to 20 kt or less by early Sat morning, with seas less than 8 ft. A ridge centered offshore of California dominates the offshore waters off Baja California. Afternoon scatterometer data indicated mainly fresh northerly winds offshore Baja California Norte, while moderate north to northeast were west of Baja California Sur. Recent observations suggest that fresh N to NE winds are spilling through the mountain gaps across north and central portions of the Baja peninsula and into the nearshore Pacific waters, while winds across southern portions have become more westerly. Winds will diminish to around 15 kt by morning and shift to northerly across the offshore waters. Seas of 8 to 11 ft in NW swell are noted across the area to beyond the Revillagigedo Islands. Seas are forecast to gradually subside to 8 to 10 ft by early Fri morning, and to 5 to 8 ft by early Sat morning. Elsewhere southeast of Las Tres Marias, moderate west to northwest winds prevail this evening, becoming southerly across the Gulf of Tehuantepec. Winds across this region will weaken slightly late tonight into Friday, before the next strong gap wind event is expected to impact the Gulf of Tehuantepec region. See the special features section above for more info on the Tehuantepec event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fairly strong high pressure ridging north of the western Caribbean and Central America will continue to support fresh to strong northeast winds pulsing across the Gulf of Papagayo through the upcoming weekend and into early next week, increasing to 25-30 kt Sat night and Sun night. Gulf of Panama: Moderate to fresh north to northeast winds prevail across the Gulf of Panama this evening, and will increase to fresh winds tonight into early Fri then diminish back to moderate speeds on Fri afternoon. This pulsing pattern will continue through the weekend and into early next week. Gentle to moderate northeast to east winds along with seas in the general range of 5 to 7 ft will continue elsewhere across the waters east of 90W through Mon night. REMAINDER OF THE AREA... A broad ridge extends SE across the northern forecast waters, from a 1029 mb high near 38N129W to just beyond the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ supports and area of fresh to locally strong trade winds, mainly south of 25N and west of 112W. Seas across this region are running 9 to 12 ft in mixed NE wind waves and NW swell. The trades will diminish to 20 kt or less on Fri as the ridge begins to weaken, and continue through Sat. Long-period northwest swell persists over much of the region west of 105W. The northwest swell will continue to propagate southward across much of the region west of 98W by late Fri while gradually decaying. A strong cold front is forecast to approach to the NW corner of the forecast region by Sun. Strong to near gale force winds are expected ahead of the front with seas building to 12 or 13 ft in long period NW swell. $$ Stripling