000 AXPZ20 KNHC 120321 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Oct 12 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURE... Tropical Storm Sergio centered near 24.7N 115.4W at 0300 UTC or 170 nm W of Cabo San Lazaro Mexico moving NE at 20 kt. Estimated minimum central pressure is 994 mb. Maximum sustained winds are 50 kt with gusts to 60 kt. Scattered moderate isolated strong convection is noted within 180 nm north of the center. Sergio will make landfall along the coast of central Baja California in about 12 hours near 26.7N 113.0W Fri morning, continue across the Gulf of California Fri, then weaken and dissipate inland over NW Mexico Fri night. Large swell associated with Sergio will spread east across the offshore waters with seas of 16 to 24 ft reaching the west coast of Baja overnight and Fri, with conditions improving Fri night. Expect seas to subside to less than 8 ft by early Sat. Refer to the NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for additional details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 13N88W to 15N108W, where it loses identity in the broad cyclonic circulation associated with Sergio. Scatterometer winds indicate the monsoon trough resumes SW of Sergio at 13N120W and continues to beyond 09N140W. Scattered moderate convection is observed within 75 nm either side of a line from 12N99W to 07N116W. Scattered moderate isolated strong convection is within 150 nm south of the axis west of 122W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features paragraph above for information on Tropical Cyclone Sergio. Gulf of California: Light southerly winds will increase tonight, with tropical storm conditions and seas to 14 ft expected late tonight through Fri afternoon. Moderate west flow is expected by late Fri night as Sergio continues further inland. Fresh northwest winds are forecast north of 30N late Sun night. Farther south, gentle to moderate westerly flow and 5 to 8 ft seas are forecast through Fri. Model guidance shows a surface low developing just southwest of the Gulf of Tehuantepec on Fri night, with the low moving northwest to near 16N103W on Mon. 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... Moderate to fresh southwesterly monsoonal flow will continue across the region through the weekend, with widespread moderate to heavy showers expected to continue along the Pacific coast of Central America. Long period cross-equatorial southwest swell will maintain 5 to 8 ft seas across the forecast area. Looking ahead, global models are indicating development of low pressure over the southwest Caribbean. The low will move west 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. Mixed swell seas generated from Sergio will subside through Sat as the pressure gradient relaxes across the waters north of 20N and west of 120W. A cold front will approach the NW portion on Mon. Moderate to fresh monsoonal flow will continue across the southern portion with seas to 8 ft. $$ Mundell