000 AXPZ20 KNHC 310325 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0315 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Gale force northerly winds of 30 to 45 kt extend sw to near 13.5N96W with associated seas of 11 to 17 ft. The highest seas are expected downstream of the Gulf of Tehuantepec near 14.5N95.5W. The gale force winds are expected to persist through sunrise on Tue. The associated n 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 93W and 103W, and as far sw as 10N112W on Tue before beginning to subside. Minimal gale forces winds are possible on Thu and Fri nights. EPAC Gale Warning: A cold front has moved into the discussion area from 32N137W to 25N140W with scattered moderate isolated strong convection observed to the n of 24N within 120 nm e of the front. The parent low pressure center is currently nw of the area near 35N145W, with cyclonic minimal gale force s to sw winds extending into the discussion area w of a line from 32N132W to 23N140W. As the cyclone shifts eastward and begins to occlude on Tue, the area of gale force conditions will extend s across the waters from 28N to 32N w of 138W. Additionally, large seas of 12 to 20 ft are expected w of a line from 32N132W to 21N140W. The gale conditions will shift n of 32N on Wed as the front slows along a position from 32N127W to 23N138W where it becomes stationary sw to 16N138W. Associated winds will diminish to 20 kt or less on Thu night. Seas will also subside late in the week with 7 to 9 ft seas, primarily in nw swell, across the waters w of 110W by late Fri. 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 sw off the Pacific coast of Colombia from 04N77W to 00N82W to 03.4SN103W where it merges with a southern hemisphere ITCZ. Another surface trough is analyzed from 07N87W to 01N96W to 03N103W where scatterometer winds indicate that the northern hemisphere ITCZ forms, and continues wnw through 10N130W to 09N140W. Although there is currently only isolated showers observed along the ITCZ, isolated moderate to occasionally strong convection is noted to the s of 05N and e of 95W. Surface troughs are analyzed from 11N113W to 17N108W and from 10N123W to 15N114W with scattered moderate convection flaring occasionally within 75 nm of the troughs. ...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: A moderate nw breeze is expected across the entire gulf waters tonight into early Tue when the pressure gradient will further relax supporting light and variable winds throughout the gulf through Thu. Light winds forecast across the EPAC waters w of the Baja Peninsula through Fri with 4 to 6 ft seas. Another round of large nw swell in the form of 8 ft seas or greater will arrive near 30N120W late Thu and reach the Baja coast n of 27N on Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulfs of Papagayo and Fonseca: Pulsing strong ene winds are expected across the offshore waters from roughly 09N to 12.5N this week, with the maximum seas building to 10 ft near 09N90W. The resultant ne swell will merge on Tue and Wed with the nw swell propagating se from the strong gap event in the Gulf of Tehuantepec. Gulf of Panama: A 60 nm wide band of fresh to locally strong n winds from the western Gulf of Panama to 03N81W are expected through late Tue, with seas building to a maximum of 9 ft. 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 EPAC gale associated with a cold front mentioned in the Special Features section above, an earlier pulse of northwest swell in the form of 7 to 11 ft seas are still observed w of 130W. The post frontal swell will propagate se across the open Pacific waters, merge with the current swell, and reach along 115W late this week. $$ Nelson