000 AXPZ20 KNHC 170331 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Dec 17 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...The Gale Warning in effect for the Gulf of Tehuantepec have been discontinued. Regional coastal observations suggest that winds are diminishing as forecast by the global models, and are likely down to 20-25 kt this evening, and should reach around 20 kt only across the immediate Gulf of Tehuantepec later this evening, and then less than 15 kt by Saturday morning. A stronger cold front over the weekend could produce a more significant northerly gale wind event beginning on Monday. Currently, marine guidance suggests northerly winds of 35-45 kt and building seas of 14-18 ft by Monday evening with this next strong gale wind event. Gulf of California...A cold front approaching the region from the west has moved through San Diego and southern California and is forecast to enter Baja California Norte during the next few hours and move eastward across the region, including the northern part of the Gulf of California overnight. Expect strong westerly winds north of 29N over the far northern Gulf this evening ahead of the front, then veering to the northwest and briefly increasing to minimal gale force tonight into the early morning hours of Saturday as the front moves east of the area. Strong northwest to north winds will then spread southward across the Gulf of California Sat and Sat night as the front moves southeastward into central Mexico. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 1010 mb low pressure near 05.5N80.5W to 08N88W to 07N100W. The ITCZ continues from 07N100W to 1010 mb low pressure near 10.5N111.5W to 07.5N123W to beyond 08.5N140W. Scattered moderate to strong convection is noted from 09.5N to 16N between 104W and 114W, and within 90 nm N of the ITCZ between 119W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale warnings is in effect for the Gulf of California. See Special Features section above for details. High pressure west of Baja California that past few days has continued to slowly weaken and drift southeastward, ahead of an approaching cold front that is nearing Baja California Norte, currently from 30N118.5W to 27N127W. Gentle to moderate northerly winds of the past 2 days have backed to the west and northwest early tonight and will gradually increase to around 15 kt later this evening. The cold front is expected to move across the N waters from west to east tonight through Saturday, and will bring fresh to strong NW flow to the waters off of Baja California Norte behind the front by early Saturday, with seas building to 8 to 10 ft behind the front. Fresh NW winds and 5 to 8 ft seas will spread south across the waters off of Baja California Sur during the day Saturday. These winds and seas will diminish late Saturday through Sunday as high pressure builds eastward behind the front. Elsewhere offshore of Mexico, and outside of the Gulf of Tehuantepec and Gulf of California, gentle to moderate breezes and 3 to 5 ft seas will persist. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong northeast winds are expected across the Gulf of Papagayo during the overnight and early morning hours through Monday, with the assistance of the nocturnal drainage flow. 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 and southern portions of PMZ111 off El Salvador and Guatemala Monday night into Tuesday morning, as strong trade wind flow in the southwest Caribbean funnels across Central America. Marine guidance indicates fresh to strong winds across the Gulf of Fonseca and the Gulf of Papagayo extending westward to beyond 92W/93W by Tuesday morning, with seas building up to 10-11 ft W of 90W. Moderate northerly winds are expected across the Gulf of Panama at that time. REMAINDER OF THE AREA... A cold front extends from 30N118.5W to 27N127W then becomes a weakening front to 25N140W, and will continue to move east- southeast across the N waters through Saturday. This will keep the subtropical ridge fairly weak, with moderate to locally fresh trade wind flow in the deep tropics. However, the trade winds will increase across the west-central waters this upcoming weekend as strong high pressure builds north of the area behind the front. Trade winds in the 20 to 25 kt range are anticipated from 10N to 18N W OF 130W Saturday morning, and from 08N to 13N W OF 135W, and from 13N to 18N W OF 130W Sunday morning. Fresh to strong NE-E winds are forecast to blow across most of the waters N of 07N W of 130W and N of 16N W of 123W by Sunday night. These marine conditions are expected to persist on Monday, with winds likely increasing to 30 kt and seas building to 11-12 ft across the west-central waters. A weak 1010 mb surface low is centered along the monsoon trough near 10.5N111.5W, with a surface trough extending north to 15N. Winds have diminished to 15 to 20 kt in the vicinity of this low early tonight. The surface low will gradually weaken to a trough through Saturday as it drifts west across the tropics. As this occurs, the accompanying broad low level cyclonic circulation, and surface trough will persist a couple of more days, and reach near 120W by Sunday night. While winds and seas in the vicinity of this feature are not strong, very active weather continues with this wave-like feature and is expected to shift westward with it through at least Saturday. $$ Stripling