000 AXPZ20 KNHC 210348 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...SPECIAL FEATURES... Tropical Storm Roslyn is centered near 15.7N 103.6W at 21/0300 UTC moving WNW at 7 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas are near 14 ft. Numerous moderate to isolated strong convection is noted from 13N to 18N between 101W and 105W. Roslyn will turn toward the northwest by Fri, followed by a NNW motion on Sat and a N motion Sat night into Sun. Roslyn is expected to move parallel to the southwestern coast of Mexico through Sat, then approach the west-central coast of Mexico on Sat night and Sun. Strengthening is forecast during the next couple of days or so, and Roslyn is expected to become a hurricane by late Fri. Seas will build to 20 ft by Fri afternoon and near 30 ft by Sat. Heavy rainfall from Roslyn could lead to flash flooding and possible landslides in areas of rugged terrain over coastal southwestern Mexico. 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. Gulf of Tehuantepec Gale Warning: High pressure north of the area has started to shift eastward and weaken. Gale force winds continue across the Tehuantepec region through tonight. Winds will continue to diminish to 20 kt or less by Sat. Seas are peaking near 12 ft and will drop below 12 ft by tonight. Please refer to the latest NWS High Seas Forecast at https://www.hurricanes.gov/marine for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 89W north of 04N, moving west at around 10 kt. Numerous moderate to scattered strong convection is noted along the Central American coast from 12N to 14N between 87W and 94W. Scattered moderate convection is noted from 06N to 08N between 89W and 92W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 12N97W and from 12N110W to 11N124W to near 10N140W. Scattered moderate convection is from 06N to 11N between 84W and 93W and from 08N to 13N between 106W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on Tropical Storm Roslyn, and on a gale force gap wind event in the Gulf of Tehuantepec. Elsewhere, mainly light to gentle N-NW winds are west of 110W as well as in the Gulf of California. Gentle to moderate northerly winds are west of Tropical Storm Roslyn to 112W. 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 is near 15.7N 103.6W 1001 mb at 8 PM PDT and moving WNW at 7 kt. Maximum sustained winds 45 kt gusts 55 kt. Roslyn will move to 16.0N 104.4W Fri morning, strengthen to a hurricane near 16.7N 105.3W Fri evening, 17.9N 106.2W Sat morning, 19.5N 106.6W Sat evening, 21.3N 106.5W Sun morning, and move inland and weaken to a tropical storm near 23.4N 105.6W Sun evening. Roslyn will dissipate late Mon. Gale force winds in the Gulf of Tehuantepec will continue through tonight, then winds will then gradually diminish by 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 late Sun into early next week with building seas to 8 to 10 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 8 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. Numerous moderate to isolated strong convection is noted across El Salvador and Guatemala coast N of 12N between 87W and 92W. For the forecast, light to gentle winds will prevail elsewhere north of the monsoon trough, pulsing to moderate to fresh offshore southern Nicaragua and the Gulf of Papagayo. Moderate to occasionally fresh S-SW winds will prevail south of the monsoon trough. REMAINDER OF THE AREA... A 1016 mb low pressure is centered near 25N133W. A surface trough extends from the low to 28N126W to 25N140W. Moderate to locally fresh N-NE winds are on the west side of the low. 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 124W. Light to gentle winds are elsewhere north of the monsoon trough. Seas are 5-7 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 low/trough will drift east across the north-central waters, eventually dissipating over the next day or so. Fresh sets of NW swell will propagate across the NW and north-central waters over the next several days, occasionally building seas to around 8-9 ft with each passing set. The largest set may arrive late in the weekend into early next week, with seas to around 11 ft near 30N Mon. Meanwhile, a set of SW swell with seas of at least 8 ft will breach 03.4S and the Equator tonight, reaching to 10N by Fri night. $$ AReinhart