000 AXPZ20 KNHC 221605 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Sep 22 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 1545 UTC. ...SPECIAL FEATURES... Broad low pressure centered within the monsoon trough approximately 740 nm south of the southern tip of the Baja California peninsula. Although presently the low is not well defined, satellite imagery shows increasing clusters of convection near it. The convection is depicted as scattered moderate to isolated strong type intensity within 60 nm of the the low in the southeast quadrant. Deeper convection is to the west of the low along and near the monsoon trough as described below. The low is forecast by the global models to become better organized over the next couple of days. A gale warning has been issued for this low beginning late Friday night as is approaches near 13N114W with 30 to 35 kt winds within 120 nm east, and 180 nm west semicircles of the low along with seas of 9 to 13 ft. By the early on Saturday. the low is forecast to be near 15N115W with gale winds of 30 to 40 kt within 60 nm of the low and seas building up to 14 ft, or possibly higher. The global models depict the low to track northwestward through Saturday, then curve N to NNE on Sunday and Monday. This system has a high chance of becoming a tropical cyclone during the next 48 hours, and through he next 5 days. Please refer to the latest Graphical Tropical Weather Outlook for more information at http://hurricanes.gov. ...Tropical Waves... A tropical wave axis is along 84W north of 08N moving w at about 15 kt. Scattered moderate convection is within 120 nm west of the wave from 05N to 06N. While deep moisture lies ahead of the wave, satellite water vapor imagery depicts dry air in its wake. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to 09N99W to low pressure near 10N111W 1006 mb to 13N121W to low pressure near 13N126W 1009 mb to low pressure near 12.5N139W to beyond 12N140W. Numerous strong from 09N to 12N between 112W and 118W. Scattered strong within 30 nm of axis between 126W and 128W. Scattered moderate to isolated strong convection is seen within 120 nm south of axis between 109W and 110W, and within 180 nm south of axis between 119W and 121W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Winds and seas along the Pacific coast of Baja California and in the Gulf of California have diminished. However, the respite will be short-lived. Seas will increase once again for the waters W of Baja California Norte this afternoon as NW swell propagate into the region. NW to N swell will cause seas to build as high as 8 ft as far S as 25N to the W of Baja California Sur before subsiding Friday night and Saturday. Farther S, satellite-derived wind data indicate that the fresh to strong gap winds that affected the Gulf of Tehuantepec yesterday have diminished to moderate to fresh speeds this morning. Light to gentle winds are generally expected over the Gulf of Tehuantepec tonight through Monday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to occasionally fresh winds will prevail N of the monsoon trough, while gentle to moderate SW winds are expected S of the monsoon trough. Seas will remain near 7 ft through Friday as long period SW swell propagate into the region. Seas will begin to subside on Saturday and lower to between 4 and 6 ft on Monday. REMAINDER OF THE AREA... A 1009 mb low pressure along the monsoon trough near 12.5N139W will slowly shift W of the area during the next couple of days. Meanwhile, a surface ridge extends from a 1026 mb high center well N of the area near 36N133W southeastward to 16N111W. The difference in pressure between the ridge and lower pressure farther S along the monsoon trough is generating moderate trades W of 120W between 15N and 25N. Trades are moderate to fresh W of 120W and N of 25N with seas in the range of around 5 to 7 ft. $$ AGUIRRE