000 AXPZ20 KNHC 232147 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2129 UTC Sat Dec 23 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 2130 UTC. ..SPECIAL FEATURES... ...Eastern Pacific Gale-Force Winds... A 1007 mb extratropical low centered near 29N140W is moving NE and will clip our area of discussion this evening. Gale force winds to the east of the low will cross a portion of the NW waters as the low moves over the area. The low will then weaken tonight as it lifts north of 30N, with gale force winds ending over our area tonight. Strong southerly winds will extend as far S as 23N today and as far E as 133W. Seas will build as high as 15 ft today under the swath of gale force winds, with 8 to 12 ft seas under the broader area of 20 to 30 kt winds. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...Gulf of Tehuantepec Gale-Force Winds... A strong cold front entering the NW Gulf of Mexico today will induce a gap wind event in the Gulf of Tehuantepec. Strong N to NE winds will develop over the Gulf of Tehuantepec by this evening with winds to gale force. These winds persist for several days. Seas in the Gulf should peak around 12 ft on Monday morning, then remain 8 ft or greater through at least Wednesday night. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 06N77W to 07N100W. The ITCZ continues from 07N100W to 08N117W to 08N130W to 10N140W. A surface trough extends from 16N116W to the ITCZ axis near 10N117W. Scattered moderate convection is from 06N to 09N between 114W and 120W. Isolated moderate convection is within 120 nm of the ITCZ axis W of 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section above for details on the Gulf of Tehuantepec Gale event. Gulf of California: The fresh to strong winds that have been over the Gulf the past day or so will continue to linger mainly S of 28N as NW winds continue to funnel across the Gulf from high pressure N of the region. The flow will begin to diminish by tonight as pressures over the SW United States fall. Benign marine conditions are then expected over the Gulf through the middle of next week. Gentle to moderate winds and seas of 4 to 6 ft will prevail elsewhere into mid week next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong gap winds over the Gulf of Papagayo will continue pulsing through Wednesday night. Seas will peak around 8 ft. NE swell to 9 ft will clip the western offshore waters of Guatemala Monday and Tuesday as swell disperse from the Gulf of Tehuantepec gap wind event. Otherwise, gentle to moderate winds and seas of 5 to 7 ft can be expected during the next several days. REMAINDER OF THE AREA... See the Special Features section above for details about the gale-force wind event for the waters near 30N140W. Scattered moderate convection is currently occurring N of 16N and W of 135W over the discussion waters associated with this system. Elsewhere, moderate to fresh winds will prevail with seas between 6 and 8 ft. Early next week, NW swell generated by the Special Features' low will slowly propagate SE into the discussion waters by early Tuesday, then merge with an area of 8 ft seas associated with trade-wind waves and swell on Wed. The area will span to the W of 110W from 10N to 20N by that time. $$ Formosa