000 AXPZ20 KNHC 221556 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1530 UTC Fri Dec 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ..SPECIAL FEATURE... ...Eastern Pacific Ocean Gale-Force Winds... A 1007 mb extratropical low at 22N147W west of our area is anticipated to intensify during the next 24 hours and move northeastward during the next couple of days. The 0614 UTC ASCAT scatterometer pass this morning indicated that strong breeze conditions were already occurring near 20N140W. This system will clip our northwestern corner and briefly produce gales Saturday morning. By late Saturday, however, the system will be weakening and moving past our northern 30N border. By Sunday morning, winds in our area will drop below 20 kt. Combined SE wind waves and NW swell should produce peak seas around 15 feet near 30N140W on Saturday. A lingering NW swell of about 8 to 11 ft will slowly move southeastward through Tuesday. Please read the latest high seas forecast under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from low pres of 1009 mb near 09N77W to 07N90W to 07N104W. The ITCZ continues from 07N104W to low pres of 1012 mb near 09N114W to 09N130W to beyond 09N140W. Scattered moderate convection is from 09N to 20N between 105W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: NW fresh to strong winds are likely occurring throughout the entire Gulf this morning, though no observations have been available. Peak seas are likely up to 8 ft. Gaps in the Baja California mountains are allowing some NE winds to emerge on the Pacific coast. These winds will gradually weaken by Sunday morning as the high pressure in the southwestern United States slowly dissipates. Gulf of Tehuantepec: A strong cold front moving southward across the Gulf of Mexico on Saturday will induce a gap wind event in the Gulf of Tehuantepec starting Saturday evening. Gale conditions are expected Monday morning through Tuesday morning. The global models have come into better agreement on the timing and magnitude of this event. Peak seas are anticipated to reach around 13 ft on Monday morning and remain 8 ft or greater through at least Wednesday morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong Gulf of Papagayo gap winds will continue through Saturday night. Winds will increase slightly Sunday morning and continue through at least Wednesday morning. Peak seas will reach up to about 8 ft. NE swell to 9 ft will clip the western offshore waters of Guatemala Monday and Tuesday due to the Gulf of Tehuantepec gap wind event. Otherwise, gentle to moderate winds and seas of 5 to 7 ft can be expected the next several days. REMAINDER OF THE AREA... See the Special Feature section above for details about a Gale Force Wind event for Saturday in our northwestern waters near 30N140W. Scattered moderate convection is occurring well ahead of this system over our waters N of 19N and W of 137W. Elsewhere, moderate to fresh winds prevail with seas mainly between 6 and 8 ft. Early next week NW swell from the departing special features low will slowly propagate SE over our waters, reaching W of a line from 30N125W to 18N125W to 10N138W by early Tuesday. $$ Latto