000 AXPZ20 KNHC 200938 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Aug 20 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... The center of Tropical Storm Kay at 20/0900 UTC is near 19.5N 113.0W, or 120 nm to the west-northwest of Socorro Island, and 265 nm to the southwest of the southern tip of Baja California. Kay is moving northwestward, or 310 degrees, 5 knots. The estimated minimum central pressure is 1000 mb. The maximum sustained wind speeds are 45 knots with gusts to 55 knots. Convective precipitation: Numerous strong within 120 nm south semicircle, and within 30 nm n semicircle. Kay is forecast to maintain intensity until early Monday morning. Kay is forecast to weaken slightly, to a minimal tropical storm with wind speeds of 35 knots, early on Monday. Kay is forecast to weaken more, to a tropical depression early on Tuesday morning. Kay is forecast to weaken even more, to a post-tropical remnant low pressure center, early on Wednesday morning. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details, and the latest public advisory MIATCPEP2/ WTPZ32 KNHC, for more details. ...TROPICAL WAVES... A tropical wave is along 104W/105W from 17N southward moving westward 10 to 15 knots. Convective precipitation: Scattered moderate to strong within 30 nm on either side of the line from 08N100W to 10N101W to 11N101W to 12N103W, and from 08N to 11N between 106W and 108W. Isolated moderate to locally strong elsewhere from 10N to 14N between 96W and 104W. A tropical wave, that currently is in the western Caribbean Sea along 82W/84W, is forecast to move across Central America today into Sunday, and then move into the far eastern part of the Pacific Ocean near 91W early on Monday. This wave is expected to be accompanied by scattered rainshowers and thunder. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough is along 08N78W to 10N85W, to a 1011 mb low pressure center that is near 10N104W, to 08N107W. The monsoon trough starts again near 16N119W, and it continues to 13N128W, to 13N132W, beyond 12N140W. Convective precipitation: widely scattered moderate to isolated strong from 05N to 10N between 79W and 90W. Numerous strong from 21N to 23N between 105W and 106W. Isolated moderate from 10N to 16N between 117W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Tropical Storm Kay continues to impact certain sections, and it is described in detail in the special features section. A northwest-to-southeast oriented surface trough is along the eastern part of the Baja California peninsula. A surface ridge is along 21N127W beyond 27N140W. Light to moderate winds prevail outside of Kay in a relatively weak pressure pattern, which will persist into early next week. Combined seas of 4 to 7 feet outside of Kay will subside gradually early next week as Kay weakens. The ridge will break down as a weakening cold front moves southward from the north. This decaying boundary will reach from 30N132W to 26N140W by sunrise today on Saturday, where it will stall during the rest of Saturday. It is forecast to retreat westward as a weak trough into early next week. This pattern will allow for trade winds to remain relatively weak. 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, on Wednesday and Thursday of the next week. Convective precipitation: Numerous strong from 21N to 23N between 105W and 106W. This precipitation is being driven to the southwest by strong upper level winds over the that part 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 late night and early morning hours, on Tuesday and on Wednesday. Light to moderate winds will prevail on either side of the monsoon trough. Combined seas of 4 feet to 7 feet will subside gradually and slightly through early next week as supporting long period south- southwest swells decay. $$ MT