000 AXPZ20 KNHC 180924 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0915 UTC Fri Nov 18 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 0600 UTC surface analysis and satellite imagery through 0845 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec gale warning: A locally tight pressure gradient continues to support fresh to strong northerly winds and seas near 8 ft. This gradient will very temporarily slacken this afternoon, allowing for winds to briefly diminish to 20 kt or less. High pressure is then forecast to surge down along eastern Mexico toward the area with the strongest cold front of the season moving across the Gulf of Mexico to the north. Northerly winds will rapidly increase to gale force tonight, then will approach storm force Saturday night. Model guidance continues to hint at the potential for storm conditions at a minimum at 30-m if not at 10-m, and the gale warning may need to be upgraded to a storm warning later today if current trends continue. Seas will build to over 20 ft by late Saturday night. Winds will diminish below gale force by Tuesday morning, with another gale force wind event expected later next week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N83W to 08N97W to 12N110W, then resumes from 11N114W to 08N129W. The intertropical convergence zone axis extends from 08N129W to 11N140W. Scattered moderate convection is within 60 nm south of the axis east of 86W, within 210 nm south of axis between 114W and 116W, and within 90 nm south of the axis between 120W and 124W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the special features section for information on the gale warning in the Gulf of Tehuantepec. Moderate to fresh northwest to north winds with combined seas of 7 to 10 ft are observed north of 22N, west of the northern Baja Peninsula and southern California. These winds will diminish to a gentle to moderate northerly breeze through the day today, with light northeast winds by Saturday, and seas subsiding to 4 to 6 ft west of the Baja California Peninsula by late Saturday. Large northwest swell of 7 to 9 ft will reach 30N120W on Sunday morning, then reaching the Baja California Norte late Sunday, extending southward across all the offshore waters west of the peninsula by Monday night, then subsiding to less than 8 ft Tuesday. Gulf of California: Moderate to locally fresh northwest winds have spread southward. These winds will continue to blow through tonight, diminishing somewhat on Saturday. Expect light and variable winds on Sunday. Winds will become southerly and increase to fresh to strong on Sunday night, north of 29N east of troughing which will develop ahead of an approaching cold front. That front will move across the northern gulf during the day Monday. Winds will shift to northerly and gradually increase back to moderate to fresh through Tuesday night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh offshore winds are expected across and just downstream of the Gulf of Papagayo during the overnight hours through Saturday night. A persistent cyclonic circulation in the western Caribbean Sea will combine with strengthening high pressure ridging over Central America thereafter, which will increase the nocturnal drainage flow to fresh to strong into early next week. Elsewhere, light to gentle northerly winds and combined seas of 3 to 6 ft are occurring north of the monsoon trough, which continues to meander from east to west along about 09N, while moderate to locally fresh southwest flow is observed south of the monsoon trough, with combined seas of 4 to 7 ft primarily in long-period southwest swell. Little change is forecast through the upcoming weekend. REMAINDER OF THE AREA... Northwest swells of 6 to 10 ft are observed north of the monsoon trough and ITCZ. This swell will decay from northwest to southeast, however, a new reinforcing set of northwest swell is already approaching 30N140W. This set is in association with the next cold front which will breach 30N140W in the next few hours. Associated winds of 20 kt or greater should remain just north of 30N. The front will extend from 30N131W to 25N137W, becoming stationary to 23N140W by late tonight, then from 30N126W to 25N132W by late Saturday night. The set of northwest swell will continue to propagate across the waters through the remainder of the weekend and into early next week, with seas up to 15 ft skirting across 30N. High pressure ridging will build in behind the front, resulting in a tight pressure gradient across the west-central waters north of the ITCZ Sunday through early next week. Trades will increase to fresh to strong, and the northwest swell will mix with fresh northeast wind waves to produce combined seas of 8 to 11 ft. $$ LEWITSKY