000 AXPZ20 KNHC 112158 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Oct 11 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURE... Tropical Storm Sergio centered near 23.5N 116.7W at 11/2100 UTC or 250 nm W-SW of Cabo San Lazaro Mexico moving NE at 20 kt. Estimated minimum central pressure is 994 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Scattered moderate isolated strong convection is noted within 180 nm over the quadrant surrounded by scattered moderate convection elsewhere within 150 nm of center. Large swells associated with Sergio will spread east across the offshore waters with seas of 12 to 18 ft reaching the west coast of Baja this evening and continue overnight and through Fri morning with conditions improving on Fri night. Expect seas to subside to less than 8 ft by early Sat west of Baja. Refer to the NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for additional details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends southwest off the Pacific coast of Mexico at 14N87W to 16101W 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 14N124W and continues southwest through 10N130W to beyond 10N140W. Scattered moderate isolated strong convection is observed within 75 nm either side of a line from 08N78W to 07N81W to 09N85W, within 150 nm either side of a line from 13N96W to 14N99W to 07N117W and within 120 nm either side of a line from 08N123w to beyond 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features paragraph above for information on Tropical Cyclone Sergio and the waters west of the Baja California Peninsula. Gulf of California: Light southerly winds will gradually become a fresh southerly breeze this evening and increase to a strong to near gale force breeze across the central gulf waters early tonight, with tropical storm conditions and seas to 14 ft, late tonight through Fri afternoon. Moderate west flow expected by late Fri night as Sergio continues further inland. Fresh northwest winds forecast north of 30N late Sun night. Farther south, gentle to moderate westerly flow, and 5 to 8 ft seas are forecast through late Fri. 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 on Mon accompanied by moderate to fresh winds and seas to about 9 ft. This low will do little to interrupt the persistent moist southwesterly flow along the southwest coast of Mexico, with coastal convection likely to continue well into next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh moist southwesterly monsoonal flow will continue across the area through the upcoming weekend 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 to locally strong winds. Looking ahead into next week, global models are indicating development of a couple of surface lows over the southwest Caribbean. One low is expected to move northwest enhancing convection across Central America. The second low will likely move west during the later portion of next week enhancing convection across Panama and Costa Rica. 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 relaxes across the discussion waters north of 20N and west of 120W. A cold front will approach the northwest portion on Mon. Moderate to fresh monsoonal flow will continue across the southern portion with seas to 8 ft. $$ Nelson