000 AXPZ20 KNHC 021605 RRA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Dec 02 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 1545 UTC. ...SPECIAL FEATURE... Gulf of California Gale Warning: Strong post-frontal high pressure will support strong winds across the Gulf of California to the north of 30N by early this afternoon, and gradually increase to minimal gale force late tonight into early on Saturday with seas building to 8 to 12 ft seas. These winds will persist through early Sat afternoon before diminishing to near gale force Saturday evening. Seas will subside to 8 to 10 ft late Saturday night. Expect the southern extent of strong to near gale force winds to reach along 26N on Saturday. As the high pressure weakens, the northwest winds will diminish to fresh intensity to the north of 27N by early Sunday afternoon, with seas lowering to 9 ft. The winds are then forecast to quickly diminish to 10 to 15 kt on Sun night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from low pressure over northwest Colombia west to just south of the Gulf of Panamas at 08N79W to 08N86W, then turns northwest to 09N96W to 10N109W to 11N120W then southwest to 10N130W where scatterometer winds indicate an ITCZ forms and extends west to beyond 10N140W. Scattered moderate convection is within 30 nm of the ITCZ between 125W and 128W, and also between 134W and 136W. Scattered moderate isolated strong convection is noted south of the eastern segment of the monsoon trough within 60 nm either side of a line from 06N77W to 06N81W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to locally strong northwest winds with 8 to 12 ft seas are expected across the waters north of 29N beyond 200 nm through tonight. Fresh north to northwest winds will follow a weak cold front within 200 nm of the Baja coast late tonight, with 6 to 8 ft reaching the coast. Fresh nw to n winds, and 7 to 10 ft seas will spread southeastward elsewhere along the Pacific coast of the Baja Peninsula on Saturday, then subside over much of the central and southern offshore waters west of the Baja Peninsula during Sunday. A surface trough extends from 20N107W through a 1010 mb surface low at 17N107W to 13N105W. This system is located near the base of a shortwave trough axis embedded within the southeast periphery of an expansive longwave trough that extends from the western U.S. southwest to northern Baja California to 24N121W to near 22N131W. Latest satellite imagery shows scattered moderate to strong convection within 180 nm of the low in the northeast quadrant. The strong west to southwest associated with the jet stream branch that rounds the base of the longwave trough is steering the aforementioned convection northeastward to inland the coast of Mexico between 18N103W and Manzanillo. This activity has moved to within 40 nm inland the coast, and likely to remain activity into this evening with possible locally heavy rainfall. The low is forecast to remain nearly stationary through early Saturday, then weaken to an eastward moving trough. Gulf of Tehuantepec: Moderate to locally fresh northerly winds are expected through sunrise this morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to locally fresh northerly winds will continue into early this afternoon, then become light and variable mainly southwest winds through tonight, gentle northwest winds Saturday and gentle southwest to west winds Saturday night and Sunday with seas in the 3 to 4 ft range. Light to gentle northerly winds, and combined seas of 3 to 5 ft are elsewhere to the north of the monsoon trough, while moderate to fresh southwest flow is noted to the south of the monsoon trough, with combined seas of 4 to 6 ft in the long-period southwest swell. Little change is forecast through Sunday. REMAINDER OF THE AREA... A nearly stationary strong high pressure system with pressure of 1033 mb is north of the area at 35N137W with a ridge extending southeastward to 32N134W to near 26N129W to near 15N115W. The pressure gradient between the ridge and troughing along southern California and northern Baja California is producing strong north winds in the northeast portion of the area north of 29N between 120W and 130W, with combined seas in the range of with 10 to 12 ft. These strong winds will reach to along 26N tonight before the gradient begins to relax with the north winds diminishing to a fresh to locally strong breeze on Sat. Strong northeast trades are expected southwest of the ridge across the tropical waters from 12N to 21N between 135W and 140W today. Seas of 8 ft or greater in mixing southwest and nortwhest swell are expected elsewhere north of the ITCZ west of 110W through the weekend. $$ Aguirre