000 AXPZ20 KNHC 090220 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 220 UTC Sat Mar 9 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from the Costa Rica coast near 09.5N85W to 06N90W. From there, the ITCZ extends to 04N100W to 02N120W to beyond 04N140W. Scattered moderate showers and thunderstorms are occurring within 90 nm north of the ITCZ axis between 95W and 115W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening cold front is drifting eastward across the northern Gulf of California. A few showers are possible just ahead of the front. Elsewhere over the Mexican offshore waters, earlier scatterometer and altimeter satellite data indicate gentle to moderate winds across the region with 4 to 6 ft seas. For the forecast, a stronger cold front will enter the area late Sun through early next week, with strong SW gap winds impacting the northern Gulf of California ahead of the front. Enhanced NW winds and large long-period NW swell will follow the front in the waters west of the whole Baja California peninsula reaching to the Revillagigedo Islands. Hazardous surf conditions are possible early next week along the coast of Baja California as a result. Looking ahead, another cold front will move southward across Baja California and the adjacent waters Wed and Wed night. This will support a strong gap wind event across the northern Gulf of California ahead of the front, followed by fresh NW winds developing over the offshore waters behind the front. Elsewhere, moderate breezes and seas will persist over the offshore waters of Mexico through mid week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... An earlier scatterometer satellite pass indicated fresh to strong NE gap winds through the Gulf of Papagayo to well west of the area. Associated downstream seas are 7 to 9 ft in this elongated plume, which consists of a mix of NE swell with a component of longer period NW swell. Fresh to strong gap winds are likely still active through the western Gulf of Panama off the Azuero peninsula. While the pressure gradient over northern Central America has relaxed a little due to high pressure farther north shifting eastward, conditions are still in place to support persistent strong to near gale force gap winds for some time across the Gulf of Papagayo and off the coast of Nicaragua. These gap winds will be strongest in the late night to early morning hours and will continue with little change through mid week. Fresh to strong N to NE gap winds also will pulse through the Gulf of Panama through mid week, mainly at night. REMAINDER OF THE AREA... Ridging is building west to east along roughly 26N in the wake of a weakening cold front over the northern Gulf of California. The ridge is supporting development of fresh trade wind flow farther south. An earlier scatterometer pass indicated a large area of 20 kt trade winds from mainly 10N to 15N west of 135W. A recent altimeter pass supported seas to 9 ft in the area of fresh winds with an added component of longer period NW swell. East of 110W, recent reports from a buoy near 08N95W support an plume of fresh gap winds extending westward from the Gulf of Papagayo region. Downstream seas associated with this elongated plume are 7 to 10 ft with a mixed NE and NW swell. For the forecast, a stronger cold front approaching the region from the northwest will move into the waters of the discussion area later tonight. The front will reach from southern California to 23N135W by Sat afternoon, then will move east of the area through Sun. Strong northerly winds will follow the front Sat night into Sun, along with reinforcing NW swell of up to 16 ft across the waters north of 20N into early next week. This longer period NW swell will decay somewhat as it moves southeast early next week, but swell in excess of 8 ft will cover the entire region west of 110W by mid week. In addition, a ridge will again build west to east over the waters north of 20N in the wake of the second front, supporting fresh to strong NE trade winds across the deep tropics south of 15N and west of 120W through mid week. Farther east, NE to E swell from the Central American gap winds will subside below 8 ft through Sat. Looking ahead, another cold front will move southward across the waters north of 25N Wed and Wed night with moderate to fresh N to NE winds developing behind the front. $$ Christensen/Reinhart