000 AXPZ20 KNHC 222137 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Jan 22 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 FEATURE... High pressure building behind a vigorous cold front moving east across the Gulf of Mexico will tighten the gradient in the Gulf of Tehuantepec tonight and allow winds to increase to gale force starting at 0900 UTC. The high will slide quickly eastward, and winds to diminish below gale force 12 hours later by 2100 UTC. Please see the latest East Pacific high seas forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 06N105W to 07N140W. No significant convection. ...DISCUSSION... ...A series of strong cold fronts and a prolonged period of unusually large swell will continue to affect most of the forecast area through Monday... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate southwest winds are ahead of a cold front west of Baja California. Large seas of 14 to 23 ft generated by the front will sweep eastward overnight. Large NW swell will continue to propagate southeastward, continuing into the deep tropics during the next several days. The pressure gradient will tighten off the Jalisco Mexico coast tonight as the front W of the area approaches, and produce a brief period of fresh to strong winds within 120 nm off the coast. Ridging behind the front will allow fresh to locally strong north winds to spread into the southern Gulf of California to near Cabo Corrientes Monday. Strong winds sustaining the swell event will diminish by Tuesday as the high weakens, with seas decreasing below 12 ft in the offshore Mexico waters Wednesday night. However, seas of 8 to 10 ft will persist west of 100W through the end of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds will prevail across most of the region through Tuesday. Seas will generally range between 3 and 5 ft until Tuesday, then build about a foot in response to building NW swell. REMAINDER OF THE AREA... The pressure gradient between high pressure centered near 31N157W is supporting strong southwesterly winds within 240 nm ahead of the front N of 27N. Strong NW winds are occurring west of the front. A large NW swell event continues spreading across the waters with 12 ft seas dominating north of 21N and reaching as high as 26 ft along 29N. Seas of 8 ft or greater encompass the waters NW of a line from 19N107W to 14N110W to 04N129W to 04N140W. Large long period swell will continue to sweep southeastward with 8 ft seas nearing the equator early Monday. Global models continue to show gale force winds associated with the cold front currently crossing the northern waters will remain just north of 30N through tonight. These winds will continue to generate NW swell. Seas of 18 to 24 ft can be expected west of the front where the near gale winds are occurring. Forecast models are in general agreement in developing low pressure over the western waters near 12N134W on Thursday and Thursday night. A large area of fresh to strong winds will be possible in the vicinity of the low from 12N to 26N W of 120W by Friday morning. $$ Mundell