000 AXPZ20 KNHC 100322 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Nov 10 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 0300 UTC. ...SPECIAL FEATURES... A gale warning is in effect for the Gulf of Tehuantepec. Strong to to minimal gale force northerly winds are expected across the Tehuantepec area this evening through late Thursday night. Then, fresh to strong northerly winds, in the 20-30 kt range, will continue to surge into the Gulf of Tehuantepec through Monday. A ridge is forecast to persist across eastern Mexico and the western Gulf of Mexico over the next several days. Seas are forecast to build to 11 ft in and downstream of the Gulf with seas of 8 ft reaching near 100W by Thursday night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 07N95W to 1009 mb low near 12N108W to 09N120W. The ITCZ axis extends from 12N126W to 12N140W. Scattered moderate convection can be found from 09N to 15N between 102W and 110W, from 09N to 11N between 110W and 115W, and from 12N to 14N between 121W and 123W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A gale warning is in effect for the Gulf of Tehuantepec. Please, see Special Features section for details. For the Gulf of California...high pressure building across the U.S. Great Basin and Rocky Mountains will support fresh to locally strong northwest winds over the northern Gulf this evening through early Friday morning. Expect seas building to 5-6 ft winds these wind speeds. Elsewhere...another set of long period NW swell has reached the waters W of Baja California. Seas of 8-12 ft will dominate the offshore waters W of 112W by early Thursday morning. This swell event will reach the Revillagigedo Islands by late Thursday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds are expected in the Gulf of Papagayo during the overnight and early morning hours through the weekend, with seas building to 5-6 ft downstream of the Gulf. Elsewhere, light to gentle winds will prevail over the waters north of 10N, with gentle to moderate mainly SW winds S of 10N. Seas of 4 to 6 ft will persist across the region through the end of the week in mixed NW and SW swell. REMAINDER OF THE AREA... A 1018 mb high pres is located near 28N132W and extends a ridge to near 20N120W. The pressure gradient between the high and lower press in the vicinity of the ITCZ is resulting in an area of moderate to fresh trade winds between 12N-20N W of 124W based on the most recent scatterometer data. A 1011 low pres is analyzed near 14N122W. A cluster of moderate to isolated strong convection is noted within about 75 nm SE quadrant of low center. A surface trough extends from 17N118W to the low center to 10N126W. Another area of low pressure is near 12N108W or about 475 nm south-southwest of Manzanillo, Mexico. This system is accompanied by a large area of disorganized showers and thunderstorms. Strong upper-level winds currently affecting this low are expected to increase during the next few days, and development, if any, should be slow to occur while the low moves northwestward and then northward at 5 to 10 kt. Long period NW swell, with significant wave heights as high as 16 ft, will continue to propagate SE across the forecast waters over the next several days. The leading edge of this swell event, with wave periods between 20 to 21 seconds, will reach from Los Cabos to the Equator at 135W tonight, and from near Acapulco to beyond the Equator and 120W Thursday night. Seas of 8-12 ft will dominate the waters NW of a line from 23N110W to the Equator at 132W on Thursday. Additional pulses of NW swell will reach the NW corner of the forecast region early on Friday as another cold front moves into the discussion area. These sets of large, long period NW swell are associated with powerful storm systems over the north central Pacific. $$ GR