000 AXPZ20 KNHC 010331 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Feb 1 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Eastern Pacific Gale Warning: A cold front is moving across the NW waters and extends from 30N132W to 25N134W to 19N140W. The front is associated with a deep 992 mb low pressure system located near 34N142W. The most recent scatterometer data showed strong to gale force SW to W winds N of 27N W OF 136W behind the front, while fresh to strong southerly winds are noted ahead of the front, particularly N of 24N and within about 120 nm E of front. The combination of the strong winds and long period northwest swell in the wake of the front is resulting in seas up to 19-20 ft within the area of gale force winds. A few showers are along the frontal boundary, mainly N of 25N. The front will continue to move SE across the N waters, reaching a position from 30N130W to 24N134W to 18N140W by early Wednesday morning, and from 30N128W to 22N133W to 17N140W by Wednesday evening. The low pressure will support a tight pressure gradient across the far NW waters allowing the gale force winds to persist west of the front through late Wednesday. SW-W winds of 20-30 kt are expected behind the front by Wednesday evening with seas up to 15-16 ft. The swell event will continue to propagate across the forecast waters over the next 36-48 hours. 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 from 04N87W to 01N98W to 01N105W. The intertropical convergence zone axis extends from 05N128W to 04N135W to beyond 05N140W. No significant convection. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: fresh to strong northerly winds will continue to blow across this gulf over the next 48 hours, particularly at night, with the assistance of the nocturnal drainage flow. Marine guidance suggests that winds will increase again to minimal gale force Thursday night and will likely continue through Sat morning. Seas are forecast to build again to around 11 ft with this gap wind event. Weak high pressure of 1020 mb located just west of the offshore zones near 27N121W is supporting gentle to moderate breezes across area, to include the Gulf of California. Seas are mostly 4-6 ft in open waters. Looking ahead, a new round of northwest swell will move into the waters off Baja California Norte late Thursday into Friday with seas of 4 to 6 ft, building to 8 ft N of 28N. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulfs of Papagayo and Fonseca: Pulsing strong NE-E winds are expected across the offshore waters from roughly 09.5N to 12N through the week, with the maximum seas building to 10 ft near 09N90W. The resultant northeast swell will continue to merge and mix with the northerly swell from the gap wind event in the Gulf of Tehuantepec. Gulf of Panama: A 90-120 nm wide band of fresh to strong N winds are expected in and downstream of Gulf of Panama to near 04N-05N through the next 48 hours, with seas building to 8 ft. Light to gentle winds, and combined seas of 3 to 5 ft, are occurring elsewhere outside of the swells originating near the gap wind regions. REMAINDER OF THE AREA... A Gale Warning is in effect for the NW waters in association with a cold front. See Special Features section above for details. Otherwise, a couple of weak surface troughs are noted E of the ITCZ between 110W and 128W. Additional pulses of NW swell will continue to propagate across the waters N of 05N W of 125W on Wednesday, and N of 05N W of 120W on Thursday. An area of seas in the 8-9 ft range is noted from the Equator to 12N between 90W AND 110W. These wave heights are the result of mixed swell and will continue to propagate westward. The aerial extent of these seas will decrease over the next 48 hours. $$ GR