274 AXPZ20 KNHC 040900 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Oct 4 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Hurricane Sergio is centered near 14.4N 118.8W 943 MB at 0900 UTC, well SW of Baja California, moving NW at 7 kt. Maximum sustained winds are 120 kt with gusts to 145 kt. Little change in intensity is expected during the next 24 hours as Sergio continues to move NW. Numerous moderate to strong convection is within 120 nm of its well defined eye, while bands of scattered moderate to strong convection are occurring elsewhere within 150 nm N and 270 nm S of the center. Large swell generated from Sergio will impact the Pacific coasts of Mexico and southern California during the remainder of this week. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N89W to 12N103W to 14N114W, then resumes west of Sergio from 12N125W to 11N134W to 10N140W. Scattered moderate isolated strong convection is within 30 nm north and 90 nm south of the trough axis west of 126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for information on the impacts of Hurricane Sergio. A frontal trough extends from 31N125W to 27N129W. The trough will become diffuse by the time it reaches the Baja Peninsula on Fri. Building high pressure behind the boundary will strengthen NW winds by late Thu, with building seas in NW swell. Southerly swell from Sergio will also move into the region to further increase sea heights. Large dangerous surf will dominate the coastal zones into the weekend, including the entrance to the Gulf of California. Gentle NW to W winds will prevail across most of the Gulf of California today. As high pressure builds across the area tonight and Fri, NW winds will freshen across the Gulf. Moderate NW winds generally prevail across the waters between Cabo San Lucas and the Gulf of Tehuantepec for the next few days, while large SE swell from Sergio dominates area seas. In the Gulf of Tehuantepec, offshore northerly gap winds of 20 to 25 kt may pulse to 25 kt during overnight hours through Fri. Seas will reach 9-10 ft during the period of strongest winds. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will meander between 09N and 12N, with fresh to strong southwesterly flow and building seas to 9 ft expected S of the monsoon trough E of 100W through Sat as a broad low pressure area develops across the western Caribbean and Central America. REMAINDER OF THE AREA... See Special Features above for information on Hurricane Sergio. As mentioned above, a frontal trough across the northern waters will gradually become diffuse during the next 24 hours, and the remnants of the old front are expected to shift eastward across Baja California Norte early Fri. NW swell behind the trough will build seas to 9-10 ft later today, then merge with the large and growing area of mixed swell associated with Hurricane Sergio on Fri. $$ Mundell