000 AXPZ20 KNHC 211524 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1520 UTC Sat Jan 21 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURE... High pressure building over the southwestern Gulf of Mexico on Monday will force gale force winds over the Gulf of Tehuantepec beginning by 1200 UTC Monday. The high will slide quickly eastward, which will allow for winds to diminish below gale force by 0000 UTC Tuesday. Please see the latest east Pacific high seas forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for the latest details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 07N96W to 06N115W to 04N130W to beyond 02N140W. Scattered moderate convection is within 120 nm of the ITCZ axis between 110W and 117W. ...DISCUSSION... ...A series of strong cold fronts and a prolonged period of unusually large swell will maintain very high seas over much of the area north of the equator and west of 100W through Tuesday... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A small area of strong southwest winds is focused north of 29N in the Gulf of California ahead of a cold front arriving over Baja California Norte this morning. The cold front extends from the NW corner of the Gulf of California to the offshore Pacific waters near 30N115W to 26N120W and is dissipating to 24N133W. Strong northwest winds and seas of 12 to 21 ft are affecting waters north of 26N in the wake of the cold frontal passage. The large northwesterly swell will continue to propagate to the southeast and will be a significant swell and high surf event that will continue into the deep tropics the next several days. By Sunday morning, seas will build to 20 ft off Baja California Norte and Guadeloupe Island. The leading edge of 12 ft seas will reach Socorro Island by late Sunday morning. Ridging behind the front will allow strong northerly winds to spread to the southern Gulf of California and off Cabo Corrientes by late Sunday. Another cold front will produce a reinforcing round of long period NW swell, which will maintain seas in the 12 to 20 foot range Monday through Tuesday. The strong winds supporting the longevity of the swell event will diminish into Tuesday as the high weakens, with seas finally decreasing below 12 ft offshore Mexico west of 100W by Wednesday night. However, seas of 8 to 10 ft will remain offshore Mexico west of 100W through the end of the week with additional re-enforcing swell likely. East of 100W, high pressure building in behind a strong cold front in the Gulf of Mexico will increase the pressure gradient across the Isthmus of Tehuantepec and cause gap winds to increase to gale force over the Gulf of Tehuantepec Monday morning. Please see the special features section for more details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle southeast to east winds will generally prevail across the region through Tuesday. Seas will be generally 3-5 ft in the forecast waters. Fresh to strong gap winds will pulse over the Gulf of Papagayo and Gulf of Panama Tuesday night through Wednesday night as high pressure passes north of the Caribbean basin. REMAINDER OF THE AREA... The pressure gradient between a cold front crossing Baja California Norte and another cold front approaching our northwestern waters supports strong northwesterly winds north of 26N east of 123W and strong southwesterly winds north of 27N west of 136W. A large northwesterly swell event is spreading across the waters with 12 ft seas dominating north of 21N and reaching as high as 25 ft along 30N. Seas of 8 ft or greater extend north of a line from around 20N111W to 02N140W. The large swell will continue to propagate southeastward with 8 ft seas nearing the equator Sunday night, and 10 ft seas or greater north of 10N. The cold front approaching our northwestern waters will cross the northern waters later today through Monday. Global models continue to show gale force winds cutting off just north of 30N with gale force winds north of 30N and near gale north of 28N west of the cold front tonight through Sunday night. These winds will help to re-enforce the northwest swell with seas of 18 to 23 ft west of the front where the near gale winds are occurring. Elsewhere east of 100W and west of 92W, mainly gentle to moderate winds and seas of 4 to 7 ft will prevail through Monday. After Monday, swell from the northwest and from Monday's Tehuantepec event to the north will cause seas to increase to 8 to 10 ft. $$ LATTO