000 AXPZ20 KNHC 201605 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1610 UTC Sun Nov 20 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec gale warning: A strong and broad high pressure ridge continues from much of the central U.S. southward along eastern Mexico, behind a strong cold front pushing SE through the southern Gulf of Mexico. Strong gale force winds to 45 kt are howling out of the north this morning across the Tehuantepec region and spreading SW and downstream, and will persist through the day and evening, before gradually diminishing in strength and areal coverage tonight. Winds are expected to diminish below gale force Monday afternoon, although another gale force wind event is anticipated Wednesday night through at least the end of the week. Peak seas within the gales are 15 to 22 ft and will subside very slowly through Monday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N76W to 07N100W. The ITCZ extends from 07N100W to low pressure near 09N125W to 10N140W. Scattered moderate to strong convection is within 150 nm either side of axis from 81W to 93W and from 107W to 127W. . Scattered moderate to strong convection is also from 10N to 18N between 120W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the special features section for information on the gale warning in the Gulf of Tehuantepec. In the Gulf of California, winds and seas have diminished during the past 24 hours, and are generally 10 kt or less with seaslessthan 3 ft across all but southern portions, where moderate northerly flow persists and seas are running 3 to 4 ft. Low pressure is forecast to develop along a trough in the northern gulf tonight which will precede an approaching cold front. Winds will become southerly in the northern gulf on the southeast side of the low, increasing to 20 to 30 kt late this evening, with seas building 5 to 8 ft as a result. The cold front will move across the northern gulf Monday afternoon and night while weakening, with winds shifting to the north behind it. A tight pressure gradient will develop across the region by Thursday, and northwest flow will increase to 20 to 30 kt west of 110W for the end of the week with seas building up to 8 ft. Elsewhere, northwest swell continues to decay across the regional waters, with combined seas at 3 to 7 ft, the highest of which can be found in the vicinity of the Revillagigedo Islands. A cold front will move into the area from the northwest late tonight through Monday. Seas will build to 8 to 11 ft from northwest to southeast today through the early part of the week. As mentioned above, the pressure gradient will tighten across the region Thursday, and northwest winds offshore of Baja California Norte will increase to fresh to strong. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to strong N-NE winds are found across the region this morning, as a persistent cyclonic circulation in the western Caribbean Sea combines with strengthening high pressure ridging over Central America. The fresh to strong northeast winds will persist through Tuesday, and increase, or pulse to 20-30 kt late at night, before diminishing Tuesday night to Wednesday. Because of this broad cyclonic circulation in the SW Caribbean, offshore winds will also briefly pulse to fresh to strong offshore of the Gulf of Fonseca tonight. 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 3 to 5 ft primarily in long-period southwest swell. Little general change in the pattern is forecast through the start of the upcoming week. SW winds may increase to 20-25 kt by Tue across the Gulf of Panama should the SW Caribbean low pressure area become better organized. REMAINDER OF THE AREA... A cold front is sweeping across the northern waters, currently analyzed from 30N125W to 21.5N140W. Associated winds greater than 20 kt are found just north of the discussion waters, while northwest swell producing seas of 8 to 15 ft, highest along 30N, continue to propagate to the southeast. The front will weaken as it continues across the northern waters, with the swell beginning to outrun the boundary itself. High pressure will quickly build in the wake of the front, which will tighten the pressure gradient, especially across the west- central waters. Trades will then increase to fresh to strong southwest of the ridging later today through the week. A new cold front will drop into the northern waters by the end of the week ushering in a reinforcing set of northwest to north swell. $$ Stripling