234 AXPZ20 KNHC 032205 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Oct 3 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 2100 UTC. ...SPECIAL FEATURES... Hurricane Sergio is centered near 13.3N 117.9W 955 MB AT 2100 UTC, well SW of Baja California, moving NW at 8 kt. Maximum sustained winds remain 110 kt with gusts to 135 kt. Some modest strengthening is still expected during the next 24 hours or so as Sergio continues to move NW to WNW. Numerous moderate to strong convection is within 90 nm of the center, while widely scattered to scattered moderate to strong convection is occurring in bands elsewhere within 150 nm N and 270 nm S of center. A 30 nm wide eye has cleared out this afternoon, suggesting the intensification trend will continue. 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 12N82.5W TO 13N109W, then resumes west of Sergio from low pressure near 12N125W TO 12N134W to beyond 09.5N140W. Scattered moderate to strong convection is from 06N to 11.5N between 82W and 91.5W, and within 180 nm S of trough between 126W and 140W. Scattered moderate to strong convection is within 300 nm SW of the coastline between 90W and Cabo Corrientes. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for information on the impacts of Hurricane Sergio. Weak 1014 mb high pressure is nearly stationary offshore of Baja California Sur, near 25N119W, ahead of a stalling cold front extending from 30N120W to 17N140W. This pattern is producing gentle NW winds across the offshore waters of Baja, where seas are 4-5 ft in NW swell. The front will move slowly eastward tonight through Thu then become diffuse as it sweeps across the Baja Peninsula Thu evening. Building high pressure behind this weak boundary will increase NW winds to moderate to fresh by late Thu, with rising seas in NW swell. Additionally, southerly swell from Sergio will move into the regional waters beginning this evening to raise sea heights to 5-8 ft early and increase to 8-10 ft by Fri. Large and dangerous surf will dominate the coastal zones into the weekend, including the entrance and southern portions of the Gulf of California. Gentle Nw to W winds will prevail across most of the Gulf of California through tonight, except for fresh SW winds across N portions due to a thermal low center there. As high pressure builds across the area behind the weak boundary late Thu 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 are expected to pulse to near 30 kt during overnight hours through Fri. Seas of 6-8 ft will build to 9-10 ft during 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 gentle to moderate winds expected on either side of the trough axis through tonight. Fresh to strong southwesterly flow and building seas of 8 to 9 ft are expected S of the monsoon trough E of 100W Thu through Sat as a broad low pressure area develops across the western Caribbean. REMAINDER OF THE AREA... See Special Features above for information on Hurricane Sergio. As mentioned above, a weakening cold front is moving slowly across northern waters, and extends from 30N120W to 17N140W. The front will briefly stall this evening and gradually become diffuse during the next 24 hours, before the remnants shift eastward across Baja California Norte late Thu. A surface trough is west of the dying front from 30N126W TO 23N140W. NW swell behind the trough will build seas to 9-10 ft across the waters west of the trough tonight through Thu. This swell will then merge with the large and growing area of mixed swell associated with Hurricane Sergio by Fri. $$ Stripling