000 AXPZ20 KNHC 161107 AAA TWDEP Tropical Weather Discussion...updated NWS National Hurricane Center Miami FL 1107 UTC Wed Nov 16 2016 Updated Discussion section to include convection southwest of the Gulf of Tehuantepec and surface trough along 132W 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 0945 UTC. ...SPECIAL FEATURES... High pressure of 1022 mb centered over east/central Mexico extends a ridge southeastward along the east side of the Sierra Madre Oriental mountains. The associated tight pressure is bringing minimal gale force north to northeast winds within a small area over the gulf within 30 nm of a line from 16N95W to 14N9W. Resultant seas in the range of 9 to 14 ft are found downstream of the gulf waters near the location of 14.5N95W. The minimal gale conditions are expected to last into the early afternoon hours at which time winds diminish to 20 to 30 kt. The high pressure and attendant ridge are forecast to weaken this afternoon through Thursday allowing for the gradient to slacken. The winds will gradually diminish through Friday with winds over the northern portion of the Gulf of Tehuantepec becoming north at 20 to 25 kt, and seas lowering to just below 8 ft by that time. Models in very good agreement that a cold front will move across the NW Gulf of Mexico on Friday night followed by much stronger high pressure. The induced tight pressure gradient is forecast to initiate gale conditions over the Gulf of Tehuantepec late Friday night or early on Saturday. Strong gale conditions of 40 to 45 kt are expected across a large swath late Sat night with the possibility of minimal storm force conditions. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from near 11N86W to 08N95W to 10N97W to 08N116W where scatterometer data from last night indicates an ITCZ forms and continues west to 08N130W to 11N135W to beyond 10N140W. Scattered moderate isolated strong convection is observed south of the monsoon trough within 45 nm either side of a line from 07N79W to 09N84W. Scattered moderate convection is within 60 nm south of the axis between 109W and 111W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features section for details on a present gale warning in the Gulf of Tehuantepec. The remnant circulation of former tropical cyclone Tina is centered near 19N112W with a pressure of 1010 mb, and is moving westward about 7 kt. The 0516 UTC Ascat pass showed fresh winds within 90 nm of the low in the northwest quadrant and within 45 nm of the low in the northeast quadrant with seas of 6 to 7 ft. This circulation will gradually open up to a trough by Friday afternoon as it moves in a west to southwest direction to near 08N115W. Gentle to moderate northerly winds with combined seas in the 5 to 7 ft range are over the open Pacific waters off the coast of Mexico. Seas are in the 2 to 4 ft range over the Gulf of California. High pressure is strengthening north of the area and will tighten the pressure gradient off the coast of California and Baja California Norte tonight with fresh northwest winds expected this afternoon, then increasing to strong northwest winds tonight into Thursday. The associated nw swell will build seas to 11 to 13 ft north of 28N early Thursday. The gradient will quickly relax during Thursday with winds diminishing to 20 kt or less. Combined seas of 7 to 10 ft will spread south across the waters to the west of the Baja Peninsula through Friday night before beginning to subside. Light to gentle northwest to north winds are across the Gulf of California, except north of about 29N where winds are light and variable. The winds north of 29N will become light southerly winds today, then become southwest to west 15 to 20 kt along 30N tonight, and increase further to 20 to 25 kt late tonight ahead of a cold front, with strong north winds briefly in the wake of the front on Thursday morning. Scattered moderate convection observed to the southwest of the Gulf of Tehuantepec is along a narrow convergence zone within 15 nm either side of a line from 14N96.5W to 12N99W. Moisture convergence guidance from the GFS indicates that this activity will move to the west-southwest reaching near 100W on Thursday, and to near 105W as it begins to weaken. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to locally fresh ne winds are expected across and just downstream of the Gulf of Papagayo late tonight and into early Thursday morning. The cyclonic circulation associated with a broad area of low pressure developing in the southwestern Caribbean Sea may result in strong northeast flow across through the Gulf of Papagayo early next week. Light to gentle northwest to north winds and combined seas of 3 to 5 ft are expected elsewhere north of the monsoon trough, while moderate to fresh southwest flow is expected to the south of the monsoon trough. REMAINDER OF THE AREA... A weakening cold front extends from 32N128W to 29N133W, and becomes stationary to 28N140W. The cold front portion will continue to move to the southeast, and gradually become diffuse by Thursday night as another cold front enters the far northwest waters. Models suggest that mainly fresh northwest to north winds behind this front will clip the far northwest water on Friday, while fresh southerly winds will precede the front roughly along 30N between 134W and 138W. The pressure gradient between high pressure in the wake of these fronts, and lower pressure in the vicinity of the ITCZ, is maintaining a small area of fresh to strong trades from 16N to 22N west of 135W, with the area forecast to shrink by Thursday afternoon. Persistent northwest swell continues to propagate southeastward with seas of 8 to 11 ft to the northwest and north of a line that extends from near 32N122W to 20N130W to 15N131W to 11N140W. This swell will continue to propagate to the southeast and south reaching to within an area bounded by a line from 32N135W to 32N116W to 23N113W to 13N140W to 23N140W to 32N135W by early Thursday night, then diminish into Friday. A weak surface trough is along 132W from 11N to 17N. Scattered moderate convection is seen within 120 nm east of the trough. This convection is being an upper shortwave trough just to its west. The surface trough will continue westward to near 135W by late this afternoon, and to west of the area on Thursday. $$ AGUIRRE