000 AXPZ20 KNHC 312202 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Jan 31 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Eastern Pacific Gale Warning: A cold front extends over the NW waters from 30N133W to 20N140W. The front is associated with a 992 mb low pressure system near 34N143W. Recent scatterometer data showed strong to gale force SW to W winds N of 27N W OF 136W behind the front while fresh to stront southerly winds are noted ahead of the front, particularly N of 24N and within 120 nm E of front. The combination of the strong winds and longer period northwest swell is resulting in seas to 16 to 18 ft. A few showers area along the frontal boundary. The front will continue to move SE across the N waters, reaching a position from 30N129W to 24N132W to 18N140W by early Wednesday afternoon, then will weaken as it extends from 30N125W to 24N130W to 16N140W by early Thursday afternoon. Winds in the wake of the front are forecast to diminish below gale force by early Wednesday afternoon. The northwest swell will continue to propagate into the region, with seas reaching as high as 19-20 ft near 30N140W by this evening. The swell will decay gradually, but lingering combined seas of 12 to 15 ft will still be likely from 27N to 30N between 130W and 140W by late week. 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 05N88W to 01N95W to 02N107W. 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 winds will continue to blow across this gulf over the next 48 hours, particularly at night with the assistance of the nocturnal drainage flow. The associated north to northeast swell will mix with both long period southwesterly cross- equatorial swell, and long period northwesterly swell, resulting in a large area of combined seas of 8 ft or greater reaching the equator between about 90W and 110W, gradually subsiding through the week. Weak high pressure 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 3 to 5 ft in open waters. Winds and seas diminish further through mid week as the high pressure builds over the region. Looking ahead, a new round of northwest swell will move into the waters off Baja California Norte late Thursday into Friday with seas 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 strong gap wind event in the Gulf of Tehuantepec. Gulf of Panama: A 90 nm wide band of fresh to locally strong N winds from the western Gulf of Panama to near 04N81W are expected through mid-week, 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 regions. REMAINDER OF THE AREA... See Special Features section above for gale conditions in the northwest corner of the EPAC discussion area in association with a cold front. Otherwise, a couple of waek surface troughs are noted E of the ITCZ and between 110W and 127W. 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. $$ GR