000 AXPZ20 KNHC 210959 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Oct 21 2022 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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... Tropical Storm Roslyn is centered near 16.2N 103.8W at 21/0900 UTC and moving WNW at 6 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Seas are peaking around 15 ft near the center. Numerous moderate to isolated strong convection is noted from 12N to 18N between 98W and 106W. Roslyn will turn toward the NW and NNW tonight and Sat, followed by a N and then NNE motion Sat night and Sun. The center of Roslyn will move parallel to the SW coast of Mexico today and tonight, and pass near and make landfall along the coast of west- central Mexico Sat night and Sun. Rapid strengthening is expected during the next day or so, and Roslyn is forecast to become a hurricane later today. Roslyn is expected to still be a hurricane when it reaches the coast of west- central Mexico on Sunday. Seas will build to near 20 ft off the SW Mexico coast later today, and build to near 30 ft on Sat. Heavy rainfall from Roslyn could lead to flash flooding and possible landslides in areas of rugged terrain over coastal southwestern Mexico. A dangerous storm surge is expected to produce significant coastal flooding near and to the east of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. Swells generated by Roslyn are affecting portions of the coast of southwestern Mexico and will spread northward to the coast of west-central Mexico and the southern portion of the Baja California peninsula through the weekend. These swells are likely to cause life- threatening surf and rip current conditions. Please consult products from your local weather office. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP4.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP4.shtml for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 90W north of 04N, moving west at around 10 kt. Convection is discussed below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends off the Costa Rica coast near 10N85W to 13N97W. The monsoon trough resumes near 13N108W to 11N124W to beyond 10N140W. Scattered moderate isolated strong convection is noted from 05N to 14N between 77W and 92W. Scattered moderate convection is noted from 07N to 14N between 106W and 136W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on Tropical Storm Roslyn. Strong to near gale-force N winds are present across the Gulf of Tehuantepec with seas 8 to 10 ft. Elsewhere, mainly light to gentle N-NW winds prevail across the Baja California offshore waters, Gulf of California and off the SW Mexico coast. Seas are 4-6 ft in NW swell west of Baja California and SW Mexico. Seas are 1-3 ft in the Gulf of California. For the forecast, Tropical Storm Roslyn near 16.2N 103.8W 998 mb at 2 AM PDT moving WNW at 6 kt. Maximum sustained winds 55 kt gusts 65 kt. Roslyn will strengthen to a hurricane near 16.6N 104.6W this afternoon, move to 17.4N 105.5W Sat morning, 18.7N 106.2W Sat afternoon, 20.5N 106.2W Sun morning, inland to 23.0N 105.1W Sun afternoon, and weaken to a remnant low near 25.7N 103.3W Mon morning. Roslyn will dissipate early Tue. Strong winds in the Gulf of Tehuantepec will continue through tonight and diminish by early Sat. Fresh to strong winds will develop in the Gulf of California Sat night through Sun morning. A set of NW swell may propagate into the waters offshore Baja California Sun into early next week, with building seas approaching 12 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds prevail N of the monsoon trough with moderate southerly winds S of the monsoon trough. Seas are 7 ft in N to NW swell across the Guatemala offshore waters due to the Gulf of Tehuantepec gap wind event. Otherwise, seas are 4-6 ft in S to SW swell. Scattered moderate to isolated strong convection is noted across the Guatemala coast N of 11N between 89W and 92W. For the forecast, light to gentle winds will prevail elsewhere north of the monsoon trough. Winds will pulse to moderate in offshore southern Nicaragua and the Gulf of Papagayo this weekend. Moderate to occasionally fresh S-SW winds will prevail south of the monsoon trough. REMAINDER OF THE AREA... A surface trough extends from 26N128W to 25N138W. Moderate N-NE winds are on the west side of the trough. There is a weak pressure gradient over much of the discussion waters, with moderate NE-E winds north of the monsoon trough to 19N and west of 123W. Light to gentle winds are elsewhere north of the monsoon trough. Seas are 5-8 ft in mainly NW swell north of the monsoon trough and west of 120W with 4-6 ft seas east of 120W. Moderate winds are south of the monsoon tough between 100W and 115W, with gentle to moderate winds elsewhere south of the monsoon trough. Seas of 6-8 ft prevail across the waters south of the monsoon trough and west of 100W. For the forecast, the trough will drift east across the north- central waters, eventually dissipating over the next day or so. A cold front will press southward this weekend, bringing a fresh set of NW swell across the NW and north- central waters. Seas will build to 8-10 ft. The front is expected to dissipate by Sun. Another set of swell will arrive late in the weekend into early next week, with seas to around 12 ft near 30N Mon. Meanwhile, a set of SW swell with seas of at least 8 ft along 03.4S and the Equator will diminish later today. $$ AReinhart