000 AXPZ20 KNHC 171040 CCA TWDEP Tropical Weather Discussion...corrected NWS National Hurricane Center Miami FL 1005 UTC Thu Nov 17 2016 corrected header 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... Gulf of Tehuantepec gale warning: minimal gale force north to northeast winds were evident in an Ascat pass from last night in a narrow swath across the Gulf. The 06Z surface analysis reveals weaker high pressure (4 mb lower than 24 hours ago) over east/central Mexico with the associated gradient becoming weaker with time. This will allow for the gale force winds to diminish to 20 to 30 kt by around 12Z this morning with the present maximum seas of 13 ft subsiding to 11 ft. An area of 6 to 8 ft seas downstream from the Gulf from 06N to 12N between 95W and 100W will gradually shrink in coverage during the day. The 20 to 30 kt winds will continue to diminish today leaving a small patch of 20 to 25 kt winds over the Gulf by early this evening and overnight tonight with seas subsiding further to just below 8 ft. Only moderate to fresh north winds are forecast from late Fri morning through late Friday afternoon when new and stronger high pressure ridging surges southward across southeastern Mexico. Northerly winds quickly increase during Fri night behind a strong Gulf of Mexico cold front, with the flow reaching minimal gale force again late Friday night. Strong gale conditions of 40 to 45 kt are expected across a large swath of the Gulf beginning Saturday afternoon, and through Sunday night with induced maximum seas forecast to quickly build to 23 ft just downstream of the Gulf on Sunday, with the leading edge of 12 ft seas expected to spread south to southwest to near 10N between 96W and 100W and the leading edge of 8 ft seas to near 07N between 95W and 105W by then. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Costa Rica to 09N95W to 10N105W to 09N113W to 08N122W where scatterometer winds indicate an ITCZ continues from 08N122W to 07N130W to beyond 08N140W. Scattered moderate convection is seen from 10N to 13N between 116W and 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features section for a gale warning in the Gulf of Tehuantepec. The remnant low of former tropical cyclone Tina is nearly stationary near 19N113W with a pressure of 1011 mb. The low is forecast to slowly weaken to a trough by Friday night. Fresh to strong northwest winds with combined seas of 11 to 15 ft in a northwest swell are north of about 29N and west of the northern Baja Peninsula and southern California, while northwest to north winds to minimal gale force with seas of 10 to 16 ft are just north of the area between 118W and 123W. The fresh toe strong winds will diminish to 15 to 20 kt this afternoon, with the 11 to 15 ft seas subsiding slightly to 11 to 13 ft, to 10 to 11 ft early this evening with seas of 8 to 10 ft in the northwest reaching the waters along central Baja California. The northwest swell will gradually subside through Friday night with maximum seas of 9 ft forecast to be within area bounded from 32N119W to 20N112W to 17N123W to 23N126W to 32N119W at that time. By late Friday night, seas to 8 ft in decaying northwest swell is forecast to be within an area bounded from 26N118W to 18N112W to 18N119W to 23N123W to 26N118W. These seas then subside to 5 to 7 ft on Saturday. Seas north of 26N will subside to 5 to 7 ft also by late Friday night. Light and variable winds are observed across the Gulf of California to the south of 29.5N, while strong southwest winds are north of 29.5N. These winds will shift to the north this morning, then diminish slightly in the afternoon while winds become fresh and northerly south of 29.5N, and continue into late Friday night. On Saturday, northerly winds become moderate in intensity over the Gulf of California south of 30N, and gentle north of 30N. Seas build to 4 to 5 ft north of 29.5N today in the Gulf of California, and subside to 3 to 4 ft on Friday. Seas south of 29.5N are forecast to be in the 2 to 3 ft range today, and build to 3 to 4 ft tonight with little change through Saturday. 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 at night, and into the early morning hours beginning on Saturday as broad cyclonic flow in the southwestern Caribbean Sea becomes more pronounced. Light to gentle northwest to north winds and combined seas of 4 to 6 ft are occurring elsewhere north of the monsoon trough, while moderate to fresh southwest flow is occurring to the south of the monsoon trough, with combined seas of 4 to 7 ft primarily in long- period southwest swell. Little change is expected through Saturday. REMAINDER OF THE AREA... High pressure of 1027 mb is centered north of the area near 35N136W with a ridge extending southeast to near 21N118W is maintaining rather stable atmospheric conditions. Northwest swell continues to propagate southeastward with resultant seas of 8 to 11 ft to the northwest of a line from 32N116W to 15N129W to 12N40W. The southern extent of seas 8 ft or greater will reach from the central Baja Peninsula to 13N140W tonight, and then begin to subside. In the meantime, the pressure gradient between the high pressure and relatively lower pressure in the vicinity of the ITCZ is supporting fresh to locally strong northeast to east trade winds to the north of the ITCZ within an area outlined from 14N to 18N west of 137W. The high is forecast to shift eastward allowing for a cold front to move into the far northwest waters late tonight. The front will be attendant by fresh to strong southwest to west to a northwest wind shift to the north of 31N, and a 15 to 20 kt wind shift along the front elsewhere n of 28N. Wavewatch model guidance suggests that yet another round of large northwest swell will follow the front with seas of 10 to 16 ft expected to begin spreading into the northwest section of the area on Friday night with the leading edge of 8 ft seas reaching from near 32N126W to 27N132W to 23N140W by early on Saturday, and approach the northern Baja Peninsula on Sun evening. $$ AGUIRRE