000 AXPZ20 KNHC 300848 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 848 UTC Mon Jan 30 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A strong gale force wind event continues with near storm force winds. Seas in excess of 20 ft downstream of the Gulf of Tehuantepec, in a mix of local wind waves and longer period northwest swell. Combined seas of 8 ft or greater reach well downstream of the Gulf of Tehuantepec. Gap winds will diminish below gale force by Tuesday as high pressure north of the area weakens. Strong gap winds will persist through the remainder of the weak with 8 to 10 ft seas. Eastern Pacific Gale Warning: Vigorous deep layer low pressure is approaching from the northwest. Southwest winds over the northwest portion of the discussion area from 25N to 30N between 135W and 140W ahead of an associated cold front are starting to increase to minimal gale force. The winds will diminish to just below later today as supporting upper energy lifts northeast, but large northwest swell will accompany this front, which is expected to reach a position from 30N135W to 24N140W tonight, and from 30N130W to 20N140W Tuesday night. Winds will briefly increase again to gale force near 30N140W early Tuesday as reinforcing cold air pushes into the region. The front will weaken as it continues eastward across the waters north of 20N through mid week. The northwest swell will bring combined seas heights in excess of 8 ft to most of the region west of 120W through mid week...with maximum seas to 20 ft by Tuesday near the area of gales. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC for additional details on these warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends 09.5N75W to low pres near 0.5N81W 1009 MB to 04N97.5W. The ITCZ extends from 04N101W to low pres near 04.5N107W 1013 MB to 08N126W to 06N140W. Small clusters of scattered moderate to strong convection are observed within 180 NM N of the trough between 84W and 87W...and within 180 nm N of the ITCZ from 127W to 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features section above for gale conditions in and downstream of the Gulf of Tehuantepec. Gulf of California: 20 to 25 kt northwest winds across the area north of 25N are forecast to diminish to a fresh breeze by late morning, then further diminish to 20 kt or less later today. Seas will subside accordingly to less than 8 ft by late morning. Light to gentle breezes are then expected through mid week. Other than the strong gales near and downstream of Tehuantepec, moderate breezes are noted elsewhere with 5 to 7 ft seas in northwest swell. A few thunderstorms are noted around 200 nm offshore of Manzanillo related to a jet dynamics aloft, and will dissipate over the next several hours. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong high pressure north of the region will support pulses of fresh to strong east-northeast winds through mid week primarily through the Gulf of Papagayo, but also out of the Gulf of Fonseca and Gulf of Panama. Seas will reach 8 to 10 ft downstream of the Gulf of Papagayo by late today, with a component of northwest swell. Elsewhere, light to gentle winds, and combined seas of 3 to 5 ft, are occurring elsewhere outside of the swells originating near the gap events. REMAINDER OF THE AREA... Aside from the strong winds and northwest swell mentioned above in the Special Features section, an earlier batch of northwest swell of 8 to 10 ft covers much of the region south of 30N and between 120W and 140W. This will decay below 8 ft from east to west over most of this region through early Tuesday just ahead of the arrival of the new group of northwest swell into the area. $$ Christensen