000 AXPZ20 KNHC 142125 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1921 UTC Fri Apr 14 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The northern Intertropical Convergence Zone axis extends from 03N92W to 02N110W to 05N130W to 05N140W. Scattered moderate to isolated strong convection is noted within 120 nm S of axis between 120W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A tight pressure gradient between high pressure over eastern Mexico and lower pressures south of the Tehuantepec region will support fresh to strong northerly winds across the Isthmus of Tehuantepec through Saturday night. A surface ridge extends into the offshore waters while surface low pressure continues along the Gulf of California and over the northwest section of Mexico. A tightened pressure gradient between these two features continue to support fresh to strong NW winds offshore of Baja California Norte where seas are up to 8 ft. The surface trough is forecast to weaken by late this afternoon, which will allow for the pressure gradient to relax and winds to diminish to moderate to fresh category. Northwest swell, however, will continue to support seas up to 9-10 ft off the Baja California Norte through Saturday evening. Light and variable winds and seas generally below 2 ft will prevail across most of the Gulf of California during the upcoming weekend. Seas of 2-3 ft are expected near the entrance of the Gulf. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to locally strong drainage flow is expected to pulse at night tonight and Saturday. Seas are expected to build to 8 ft with these winds. In the Gulf of Panama, moderate to fresh northerly flow is expected during the overnight hours through the upcoming weekend. Seas will be in the range of 5 to 6 ft downstream of the Gulf. Elsewhere, light to gentle winds and combined seas of 3 to 6 ft will change little through the weekend. REMAINDER OF THE AREA... A set of large period NW swell is reaching the offshore waters of Baja California, building seas to 10 ft. This swell event will affect the entire coast of Baja Califorinia by tonight, and the Revillagigedo Islands by Saturday morning with seas to near 8 ft. The next cold front is forecast to reach northwest waters early Saturday afternoon, however fresh to strong S-SW winds ahead of the front will enter the region during the morning hours. A new set of northwest swell associated with this front will build seas in the range of 8 to 10 ft in the far northwest portion of the area Saturday. Seas will subside Sunday morning as the swell energy decays. The front will reach a position from 30N139W to 28N140W by early Saturday afternoon, and from 30N131W to 25N140W by early Sunday afternoon while beginning to weaken. Northerly winds behind the front are expected to start of in the generally fresh range, but diminish quickly to the gentle category during Saturday as weak high pressure builds eastward in the wake of the front. A 1028 mb high pressure located north of area near 35N130W extends a ridge SE to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ is allowing for generally fresh to strong northeast winds from 07N to 19N west of 118W, with resultant seas of 9 to 10 ft as indicated by latest available altimeter data. The high pressure will move eastward while weakening due to the approching cold front. As a result, the trades over the central and western portions of the forecast area will weaken. Then, marine guidance suggests mostly gentle to moderate trades over those sections of the area. Seas within the area of the trades will be in the 8-9 ft range due to combination of NE windwave and NW swell. $$ GR