000 AXPZ20 KNHC 081543 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1433 UTC Wed Nov 8 2017 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 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec: Northerly winds in the 20 to 30 kt range with seas of 8 to 10 ft are expected across this area through Thu morning. A cold front moving across the western Gulf of Mexico will bring another gale wind event across the Gulf of Tehuentepec begining Thursday afternoon. A gale warning is already in effect for the Tehunatepec region. Currently, marine guidance suggests increasing winds of 30-40 kt and building seas of 10-15 ft. This event is forecast to peak Thu night into Friday morning, and again Sun night into Mon morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09.5N84W to 09N100W to 08N110W to 1009 mb low pressure near 11N121W to 09N133W. The ITCZ axis continues from 09N113W to beyond 07N140W. Scattered moderate and isolated strong convection is from 05N to 08N E of 79W to the coast of Colombia, including the approach to the Panama Canal. A cluster of similar convection is near 09N100W. Scattered moderate to isolated strong convection is also from 07N to 11N between 117W and 126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge will dominate the waters W of Baja California through the rest of the week, while a trough will meander between the coast of NW Mexico and the Gulf of California. Moderate to locally fresh NW to N flow will prevail across the waters W of Baja California, increasing to fresh to locally strong offshore of the northern waters Thu night through Fri. A cold front is expected to weaken before reaching the area on Friday, but the associated long-period NW swell inducing seas in the range of 8 to 10 ft will propagate southeastward across the waters N of 23N and to the W of Baja California on Friday, then spread southward through all the waters W of Baja on Saturday while subsiding slightly. Gulf of California: The pressure gradient will tighten a little resulting in a narrow swath of fresh to locally strong NW winds from 25N to 28N by this afternoon. The pressure gradient will relax with moderate NW flow only to the S of 26N by Thursday evening. Mainly light and variable winds and seas of 2 ft or less will then prevail for the end of the week into the upcoming weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to locally fresh N to NE winds will pulse during the overnight hours through early Thu, with seas building to 5 or 6 ft downstream near 11N87W. Light and variable winds and 4 to 6 ft seas, are expected elsewhere to the N of 09N, while moderate to locally fresh southerly winds and 5 to 7 ft seas, are forecast S of 09N through the remainder of the week and the upcoming weekend. REMAINDER OF THE AREA... A 1019 mb high pressure is near 28N125W and extends a ridge SE to near Clarion Island. This system is forecast to remain nearly stationary over the next 24 hours. A surface trough is analyzed across the west-central waters and just N of the monsoon trough. The trough extends from 19N132W to 11N135W. Scattered showers and isolated tstms are near the southern end of the trough axis. A recent altimeter pass indicated seas to 8 ft between the trough axis and 140W. A 1009 mb surface low remains within the monsoon trough near 11N121W, and is generating scattered moderate isolated strong convection from 07N to 11N between 117W and 126W. A cold front is approaching the far NW corner of the forecast area followed by a new set of long period NW swell. The front will reach from 30N131W to 28N140W by early Thu morning, then become nearly stationary from 30N130W to 27N140W on Thu evening and begin to dissipate on Fri. The associated long period NW swell, with seas of 8 to 13 ft seas will propagate SE across the northern forecast waters while decaying. Seas of 8 ft or greater will cover the waters N of 15N W of 115W by late Friday, then begin to subside to near 8 ft throughout the waters by late Sun. $$ GR