000 AXPZ20 KNHC 101549 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Oct 10 2018 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 FEATURE... Tropical Storm Sergio centered near 18.4N 123.5W at 10/1500 UTC or 810 nm W-SW of the southern tip of Baja California moving NE at 11 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 50 kt with gusts to 65 kt. Numerous strong convection is noted in bands within 180 nm northeast and 120 nm southwest semicircles of center. Large swells associated with Sergio will continue to mix with long period NW swell and cross-equatorial southwest swell, creating confused seas across a large portion of the discussion waters, generally west of 100W. This swell will continue to impact the coast of Mexico during the next several days as Sergio makes its way to central Baja California Sur by Fri. Refer to the NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for additional details. ...TROPICAL WAVE... A tropical wave is analyzed north of 05N along 80W and is accompanied by scattered moderate isolated strong convection within 180 nm either side of the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends southwest off the Pacific coast of Mexico at 16N97W to 12N113W where it loses identity in the broad cyclonic circulation associated with Tropical Cyclone Sergio. Scatterometer winds indicate the monsoon trough resumes southwest of Sergio at 14N128W and continues southwest to beyond 10N140W. Scattered moderate isolated strong convection is observed along the monsoon trough within 150 nm either side of a line from 12N92W to 15N96W with this convection extending about 100 miles inland Mexico from 92W to 102W. Similar convection is noted within 30 nm either side of a line from 10N124W to 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features paragraph above for information on Tropical Cyclone Sergio. West of the Baja California Peninsula...light and variable winds are observed with southerly swell from Sergio mixing with long period northwest swell resulting in 7 to 9 ft seas throughout. The swell component from Sergio will continue to increase as tropical storm conditions approach with seas 12 ft or greater reaching most of the west coast of Baja late Thu. These large seas will result in hazardous marine conditions through late Fri. Expect seas to subside below 8 ft early Sat. Gulf of California: Light and variable winds will gradually become southerly on Thu increasing to a strong breeze across the central gulf waters on Thu night, with tropical storm conditions by early Fri. Moderate northwest flow expected by late Fri night as Sergio continues further inland. Farther south, moderate to fresh westerly flow, and 5 to 8 ft seas are forecast through late Fri. Some model guidance is hinting at a surface low developing just southwest of the Gulf of Tehuantepec on Fri night, with the low moving northwest to near 16N103W by early Mon accompanied by fresh winds. This low will maintain the moist southwesterly flow along the southwest coast of Mexico with convection likely to continue through the upcoming weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to locally fresh moist southwesterly monsoonal flow will continue across the area through the middle of next week with convection likely to continue along the Pacific coast of Central America. Long period cross equatorial southwest will maintain mainly 5 to 7 ft seas, with 7 to 9 ft conditions in the small areas of fresh winds. REMAINDER OF THE AREA... See the Special Features paragraph above for information on Tropical Cyclone Sergio. Confused seas generated from Sergio will subside from the west through Sat as the pressure gradient relax across the waters north of 20N and west of 120W. A cold front will approach the northwest portion on Mon night. $$ Nelson