138 AXPZ20 KNHC 022217 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Oct 2 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 2030 UTC. ...SPECIAL FEATURES... Satellite imagery and surface observations this afternoon show clearing skies across the northern Gulf of California, as associated moisture and energy from former tropical cyclone Rosa has moved NE and inland across Arizona. Visible satellite loops this afternoon suggest a weak low level cloud swirl is across the northern Gulf near 30.5N 114.0W, and is assumed to be portions of the remnants of Rosa. Winds to the east of this low are assumed to be S to SW at 15 to 20 kt with gusts to 25 kt, and seas 5 to 8 ft. SW swell previously generated by Rosa will continue to affect portions of the coasts of southwestern Mexico, most of the west coast of the Baja California peninsula, and southern California as it gradually fades through this evening. These swells are still producing moderate to large surf and creating life-threatening rip currents within the surf zone. See latest NWS forecasts on rainfall potential across the southwestern U.S. for more details. Hurricane Sergio continues to strengthen this afternoon, with an eye appearing in satellite imagery at 11.2N 115.1W at 2100 UTC, or about 760 m SSW of the southern tip of Baja California, moving W at 11 kt. Maximum sustained wind speed has increased to 100 kt with gusts to 120 kt. Estimated minimum central pressure is 965 mb. Some modest strengthening is expected during the next 24 hours or so, and Sergio is forecast to be near major hurricane strength Wednesday and possibly continuing through Wed night or Thu. Numerous strong convection is noted within 60 nm of center, except 45 nm across the SE quadrant. Scattered to numerous moderate to strong convection is seen elsewhere within 90 nm N and 120 nm S of the center. Sergio will turn more WNW tonight and then more NW Wed and Thu as it moves father out to sea. Large waves generated from Sergio will impact the Pacific coasts of Mexico and southern California throughout the week. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP1/WTPZ31 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the SW Caribbean near 12N76W to low pressure near 10N87.5W to 12.5N102W, where it breaks from Sergio. The trough then resumes from 13.5N120W TO 14N127W TO 12N136W to beyond 10N140W. Scattered moderate to strong convection is from 06N to 11N between 77W and 98W, and from 08N to 16.5N between 98W and 105W. Widely scattered to scattered moderate to strong convection is within 120 nm N and 150 nm S of the trough between 123W and 140W ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features above for information on the impacts of the remnants of Rosa and on Hurricane Sergio. Swell associated with Rosa is fading quickly across the offshore forecast waters W of Baja California, where seas have subsided to 4 to 7 ft. However, further south, S to SE swell generated by Sergio, is propagating northward to the waters offshore of Cabo Corrientes to Cabo San Lucas, and will build to 6-8 ft in the next few hours, and spread northward to the offshore waters of Baja this evening through the next few days. This swell has been impacting the waters and coastal zones from Guerrero to Cabo Corrientes today and will spread north and northeastward to the remainder of the Mexican offshore and coastal waters this evening through tonight. These swells will continue to produce large and dangerous surf conditions and life-threatening rip currents along the coastal zones during the next few days. In the Gulf of California, conditions associated with the remnants of Rosa are described above and continue to subside. The southerly swell from Sergio will move into southern portions of the Gulf in the next few hours and raise wave heights to 4-7 ft, and increase to 5-8 ft Wed night and Thu. Large and dangerous surf will impact coastal areas inside the southern Gulf through at least late thu. Gentle NW to W winds are expected across most of the Gulf Wed and Thu, while variable winds will prevail across far north portions. In the Gulf of Tehuantepec, offshore northerly gap winds of 20 to near 25 kt are expected to pulse to near 30 kt during the overnight and early morning hours through at least early Wed morning. Seas are forecast to build to 9 or 10 ft during the hours 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 through Fri, with gentle to moderate winds expected on either side of the trough axis through Wed. Fresh to strong southwesterly flow and building seas to 8 or 9 ft are expected S of the monsoon trough and mainly E of 97W by Thu, associated with a broad area of developing low pressure over the SW Caribbean. These marine conditions may persist through Sat. REMAINDER OF THE AREA... See Special Features above for information on Hurricane Sergio. A cold front continues to move slowly SE across the NW waters, and extends from offshore of southern California through 30N124W to 20N140W. The front will sweep eastward across the waters north of 20N Wed and Thu, but become diffuse before reaching 120W. This pattern will keep the trade wind flow minimal farther south into the deep tropics, due to a very weak pressure gradient. NW swell in the wake of the front is propagating across the NW waters this afternoon and will begin to mix with the southerly swell from Sergio across the waters east of 120W tonight and Wed. By late Thu, seas of 8 ft or greater are expected to cover most of the waters N of 10N W of 105W, including the entrance of the Gulf of California. $$ Stripling