000 AXPZ20 KNHC 111546 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURE... Tropical Storm Sergio centered near 21.5N 119.3W at 11/1500 UTC or 520 nm W of the southern tip of the Baja California Peninsula moving NE at 15 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Scattered moderate to strong convection is noted in bands within 210 nm northeast and 150 nm southwest semicircles 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 15N92W to 15N100W to 12N110W 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 14N130W and continues southwest to beyond 10N140W. Scattered moderate isolated strong convection is observed within 60 nm either side of a line from 07N79W to 09N86W and within 180 nm either side of a line from 12N90W to 15N98W to 07N111W to 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 perhaps 13 ft, late tonight through midday Fri. 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 relax 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