000 AXPZ20 KNHC 131516 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1425 UTC Sun Nov 13 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 1500 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. The pressure gradient between high pressure over eastern Mexico and low pressure within the monsoon trough is supporting minimal gale force winds over the Gulf of Tehuantepec. Wind will remain near gale force or at minimal gale force through early this week. A reinforcing cold front over the Gulf of Mexico will help increase flow through the Chivela pass into the Gulf of Tehuantepec Tuesday and Wednesday night maintaining the gale force winds. Winds over the southwest Gulf of Mexico will veer as the area of high pressure shifts eastward into the southeast United States toward the end of the week. This will decrease winds flowing through the Chivela pass and bring an end to this extended period of gale force winds over the Gulf of Tehunatepec Thursday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N78W to 09N84W to 08N92W to 09N100W. It resumes from low pressure near 17.5N107.5W to 13N115W to low pressure near 13N125W to 08N140W. Scattered moderate convection was noted within 90 nm south of the monsoon trough between 86W and 90W. Scattered moderate isolated strong convection was noted within 120 nm north and 60 nm south of the monsoon trough between 90W and 100W. Scattered moderate to strong convection was noted within 210 nm northeast quadrant of the low pressure area centered near 17.5N107.5W. Scattered moderate convection was noted within 90 nm south of the monsoon trough between 115W and 121W. Scattered moderate isolated strong convection was noted within 60 nm of the monsoon trough west of 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section above for details on the ongoing Gulf of Tehuantepec gale force gap wind event. Low pressure of 1007 mb is centered near 17.5N107.5W. There is a tight gradient between the low and high pressure over Mexico that is supporting near gale force winds in the northeast quadrant of the low. Strong upper level winds are maintaining enough shear over this system to inhibit development of the low into a tropical cyclone. The low will start to move westward today as the upper level winds become more hostile for tropical development. The low will dissipate to a trough early this week, with the trough dampening out by midweek. Active convection is affecting the southwest states of Mexico from Guerrero to Jalisco. This rainfall may lead to dangerous flash flooding and mudslides over portions of these states today. Northwesterly swell is propagating through the coastal waters offshore of Baja California with seas in the 8-10 ft range. This swell will slowly subside over the next couple of days, with seas falling below 8 ft over these waters by late Monday night. Building high pressure north of the area will tighten the pressure gradient off the coast of California and Baja California Norte by midweek. This will strengthen winds to 25 kt off the coast of Baja California Norte Wednesday night, with winds reaching gale force off the coast of California. The gale force winds will help generate another northwesterly swell which will propagate into the waters off the coast of Baja California Norte by early Thursday. Seas will peak near 14 ft early Thursday before starting to subside. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds will pulse the next several days over the Gulf of Papagayo. Winds will peak near 15 to 20 kt during the late night and early morning hours, with seas building to 5-6 ft downstream of the Gulf of Papagayo. Elsewhere, light to gentle winds will prevail over the waters north of 10N, with gentle to moderate mainly southwest winds south of 10N. A surge in southwest monsoon flow aided by developing low pressure over the southwest Caribbean will freshen winds over the southern waters early this week. REMAINDER OF THE AREA... The cold front over the northwest waters has weakened to a trough this morning. The trough will dissipate later today. Northwesterly swells associated to this cold front continue to propagate through the region with seas 8 ft or greater covering much of the area north of 10N and west of 120W. This swell will continue to spread southeastward while subsiding through the beginning of the week. Seas associated to the swell will subside below 8 ft by Tuesday. A fresh set of northwesterly swell will move into the northwestern waters Tuesday with seas peaking near 11 ft late Tuesday into Wednesday over the far northwest waters. The pressure gradient will tighten between lower pressure in the vicinity of the ITCZ and developing high pressure north of the area by Tuesday. This will increase winds to 20-25 kt over the far western waters north of the ITCZ by midweek. $$ AL