000 AXPZ20 KNHC 192101 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Aug 19 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Tropical Storm Kay centered near 18.8N 111.7W at 19/2100 UTC or 243 nm to the south-southwest of the southern tip of Baja California moving northwest at 7 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed has increased to 40 kt with gusts to 50 kt. Latest satellite imagery shows numerous strong convection within 90 nm of the center in the southwest quadrant. Scattered strong convection is elsewhere within 120 nm west and 60 nm east semicircles of center. Scattered moderate to isolated strong convection is within 30 nm of 16N113.5W. Kay is forecast to intensify slightly as it reaches near 19.3N 112.2W late tonight, and maintain strength through Saturday night. Kay is then forecast to move into a more stable environment, and across cooler sea surface temperatures on Sunday causing it to gradually weaken to a tropical depression late Monday, and then to a remnant low by early Tuesday into Wednesday. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details. ...TROPICAL WAVES... A tropical wave axis is along 101W/102W from 09N to 16N moving west at 10 to 15 kt. Scattered moderate to isolated strong convection has recently developed ahead of the wave from 12N to 15N between 103W and 105W. The tropical wave may help enhance precipitation along the coast of southwest Mexico through the upcoming weekend as it passes by just to the southwest of the area. A tropical wave, currently over the central Caribbean Sea, is forecast to move across Central America on Sunday, then move into the far eastern part of the area near 91W early on Monday. This wave is expected to be attendant by scattered showers and thunderstorms. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to 10N94W to 08N100W to 10N106W. It resumes just to the southwest of Kay at 16N115W to 15N122W to 13N126W to 10N135W. Scattered moderate to isolated strong convection is within 120 nm south of the trough axis between 125W and 121W, and within 60 nm northwest of the trough between 133W and 135W. Scattered moderate to isolated strong convection is also northwest of the monsoon trough from 12N to 15N between 135W and 137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Tropical Storm Kay continues to impact portions of the area, and is described in detail in the special features section above. Otherwise, ridging extends into the northern portion ahead of Kay with a northwest to southeast oriented trough along the western Gulf of California. Light to moderate winds prevail outside of Kay under a relatively weak pressure pattern, which will persist into early next week. Combined seas of 4 to 7 ft outside of Kay will gradually subside early next week as Kay weakens. In the Gulf of Tehuantepec, northerly offshore winds will continue to pulse to fresh levels during the late night and early morning hours with nocturnal drainage flow, potentially increasing to fresh to strong by the middle of next week. Scattered moderate convection is observed from 18N to 20N between 103W and 107W. This convection is being driven to the southwest by strong upper level winds over the that portion of the basin. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Offshore winds will pulse to fresh levels in the Gulf of Papagayo and adjacent areas during the overnight and early morning hours through the next several days. Otherwise, light to moderate winds will prevail on either side of the monsoon trough. Combined seas of 4 to 7 ft will gradually subside slightly through early next week as supporting long period south-southwest swells decays. REMAINDER OF THE AREA... A strong 1034 mb high center located well north of the area near 44N145W extends a ridge southeast through 32N140W, and to near 23N117W, with mainly light to moderate trades prevailing. The ridge will break down as a weakening cold front drops down from the north. This decaying boundary will reach from 30N132W to 26N140W by early Saturday where it will stall through the remainder of the day Saturday, before retreating westward as a remnant trough into early next week. This pattern will allow for trades to remain relatively docile. $$ Aguirre