000 AXPZ20 KNHC 100242 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0410 UTC Sun Oct 9 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...High pressure building southward over eastern Mexico and the western Gulf of Mexico will tighten the pressure gradient across the Isthmus of Tehuantepec over the next several days. This will allow the strong northerly gap winds currently spilling across the Gulf of Tehuantepec this evening to combine with nocturnal drainage effects to result in strong winds over the next few days, reaching gale force in the late evening and overnight hours. Gap winds may briefly diminish to 20 to 25 kt during the afternoon hours before surging again at night into the early morning hours. Strong to near gale force gap winds will continue to pulse across the Gulf of Tehuantepec through the end of the week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N73W to low pres near 10.5N91W to 14.5N105W to low pres near 12.5N113.5W to low pres near 11.5N119W to low pres near 11.5N124W to low pres near 09.5N129.5W to beyond 10N140W. Scattered moderate to strong convection is noted within 120 nm N and 180 nm S of trough between 91W and 106W, and within 180 nm N and 210 nm S of trough between 110W and 124W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak sub-tropical ridge axis extends from northwest to southeast across the Pacific waters to just SW and offshore of Cabo San Lucas on the southwestern tip of Baja California Sur. Light to gentle northerly breezes will persist across the region north of 20N, including the Gulf of California, through the next several days on the eastern periphery of the weak ridge. Meanwhile, light and variable winds currently across the waters between the Gulf of Tehuantepec and Cabo Corrientes will become northwest to westerly and freshen through Tuesday as the ridge builds southeastward to offshore of Manzanillo Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate southwest winds persist from 05N to the monsoon trough which is meandering north to south along roughly 10N to 11N, with light to gentle southwest breezes farther south toward the Galapagos Islands. Scattered showers and thunderstorms have shifted westward and well offshore of the coast from Nicaragua to Guatemala where light to moderate northeast winds persist. However, afternoon convection has developed across these Pacific coastal zones and should shift westward and offshore through the late evening hours. A surface low pressure has formed along the monsoon trough off the coast of El Salvador or Guatemala near 10.5N91W today with modest associated winds and seas. However as this low shifts westward over the next few days, winds will increase, especially in the waters beyond 150 nm off El Salvador and Guatemala Monday, aided in part by a plume of strong gap winds originating from the Gulf of Tehuantepec. The low pressure will continue west of the area through mid week. Elsewhere combined seas of 3 to 6 ft, primarily in long-period southwest swell, are expected across the offshore waters later in the period from the early to middle part of next week. REMAINDER OF THE AREA... High pressure of 1017 mb centered north of the area near 38.5N131W will shift southeastward through the next couple of days, ahead of a cold front moving into the far NW corner of the forecast area this evening. Areas of moderate to fresh trade winds persist north of the monsoon trough to near 20N, with seas of 5 to 7 ft. Global models are in good agreement showing a series of broad, weak, and transient low pressure areas forming along the monsoon trough, identified above. Although the model depictions differ somewhat in precise locations, there is some general agreement showing the low pressure center currently near 11.5N119W will deepen over the next couple of days and move slowly northwest, reaching near 17.5N125W by mid week. In addition, models are also showing the low pressure area that will has formed near 10.5N91W today will shift westward and gradually develop, crossing west of 120W by late Wednesday. At a minimum, strong winds and seas of 8 to 10 ft are likely with these two low pressure areas. $$ Stripling