000 AXPZ20 KNHC 160354 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 15 2016 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 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec...A Gale Warning is in effect for the Gulf of Tehuantepec until late Friday morning. Northerly winds of 20 to 30 kt this afternoon are assumed to have increased to minimal gale force this evening as high pressure builds southward across eastern Mexico behind a cold front moving across the Gulf of Mexico. Winds across and just downstream of Tehuantepec are forecast to persist at 30-35 kt through Friday morning, while seas are expected to build to 9-11 ft with this gap wind event. Winds will then diminish gradually throughout the day Friday and reach around 20 kt only across the immediate Gulf of Tehuantepec Friday evening, and then less than 15 kt by Sat morning. A stronger cold front over the weekend could produce a more significant northerly gale wind event beginning on Monday. Gulf of California...A cold front across the far NW waters west of 130W early tonight is forecast to reach northern Baja California on Friday evening and move eastward across the region, including the northern part of the Gulf of California on Friday night. Expect winds inside the gulf to increase significantly both ahead and behind this front. Model guidance suggests strong southwest to west winds ahead of the front, and strong to minimal gale force west to northwest winds behind the front, and across the northern Gulf of California Friday night into Saturday morning. Strong northwest to north winds will then spread southward across the Gulf of California Sat and Sat night as the front moves southeastward through the region. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 06N74W to 08.5N83W to 06.5N91W to low pressure near 09N103W to 08N108W. The ITCZ continues from 08N108W to 08.5N125W to beyond 08.5N140W. Scattered moderate isolated strong convection is noted within 150 nm north of axis between 98W and 112W, except for scattered moderate to strong convection from 09N to 15.5N between 102W and 107W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gale warnings are in effect for the Gulf of Tehuantepec and Gulf of California. See Special Features section above for details. Gentle to moderate northerly winds and seas of 3-4 ft continue over the offshore waters W of Baja California tonight, under the influence of a weakening ridge extending southward from a 1017 mb high pressure centered near 28N118W. The high and ridge will continue weakening during the next couple of days as a cold front currently across the NW waters moves eastward toward the Baja California peninsula. The front now extends from 1010 mb low pres near 29.5N132.5W to beyond 27N140W, and has stalled. N to NE winds of 20-25 kt and seas of 8-10 ft in N swell are found north of the front while S to SW winds of 15-20 kt and seas of 6- 8 ft are noted ahead of the front. The front will move eastward tonight and reach northern Baja California and the northern part of the Gulf of California by Friday evening. Fresh to strong NW winds will spread southward across the Pacific offshore zones N of 25N Friday night and Saturday, and reach the waters N of 23N Saturday evening, while seas build as high as 10 ft near 30N behind the front. Outside of the Gulf of Tehuantepec area, mainly light to gentle winds prevail south of Los Cabos, with seas of 3-5 ft in mixed NW and SW swell. A low pressure center located along the monsoon trough SW of the Tehuantepec region is producing moderate to fresh easterly winds across parts of forecast zone PMZ027, and very active convection from 09N to 15.5N between 102W and 107W. These marine conditions will diminish on Friday as the low continues to move west and away from the area. Much of the forecast zone PMZ027 still will experience moderate to locally fresh winds due to the ongoing gap wind event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE winds are expected across the Gulf of Papagayo during the overnight and early morning hours with the assistance of the nocturnal drainage flow during the next 48 hours. Seas should build 6-8 ft during the peak of each nights wind. A larger gap wind event appears to be in store for most of zone PMZ113 on Tuesday morning as strong trade wind flow in the SW Caribbean funnels across Central America. REMAINDER OF THE AREA... As previously mentioned, a 1017 mb high pressure is centered near 28N118W and extends a weak ridge across the NE waters. The high is forecast to shift S to a position near 23N123W in about 24 hours as the aforementioned cold front moves eastward. Expect increasing trade winds and building seas across the west- central and southwest tropical waters during the upcoming weekend as strong high pressure builds N of area behind the approaching cold front. $$ Stripling