110 AXPZ20 KNHC 202046 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Oct 20 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 1800 UTC surface analysis and satellite imagery through 2040 UTC. ...SPECIAL FEATURES... Tropical Storm Roslyn is centered near 15.5N 103.0W at 20/2100 UTC moving W at 6 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are currently near 13 ft. Numerous moderate and isolated strong convection is noted from 11N to 18N between 98W and 106W. Roslyn is forecast to become a hurricane before it passes near or over the west-central coast of Mexico late Saturday and Sunday, accompanied by strong winds and a potentially dangerous storm surge. Interests along the coast of southwestern and west-central Mexico should closely monitor the progress of this system. Heavy rainfall from Roslyn could lead to flash flooding and possible landslides in areas of rugged terrain over coastal southwestern Mexico. Swells generated by the depression are affecting portions of the coast of southwestern Mexico and will spread northward to the coast of west-central Mexico by Fri. 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. The area of high pressure will continue to shift eastward and weaken further tonight into Fri, loosening the pressure gradient. Winds will diminish below gale force late tonight, then further diminish to 20 kt or less by Sat evening. Seas are peaking near 14 ft. 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 05N, moving west at around 10 kt. Nearby convection is discussed below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N86W to 10N93W to 14N96W. It resumes from 13N109W to 10N116W to 09N138W to 11N140W. Scattered moderate isolated strong convection is noted from 03N to 08N east of 84W, from 03N to 12N between 84W and 92W, from 09N to 15N between 108W and 115W, from 10N to 14N between 120W and 125W, and from 08N to 11N between 130W 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 110W. Seas are 4-6 ft in NW swell west of Baja California north of Cabo San Lazaro, with 4-5 ft seas in mainly S-SW swell elsewhere west of Tropical Storm Roslyn. Seas are 1-3 ft in the Gulf of California. For the forecast, Tropical Storm Roslyn will move to 15.8N 103.7W Fri morning, 16.3N 104.6W Fri afternoon, strengthen to a hurricane near 17.2N 105.7W Sat morning, 18.5N 106.3W Sat afternoon, 20.0N 106.5W Sun morning, and 21.8N 106.0W Sun afternoon. Roslyn will weaken to a tropical depression while moving inland near 25.0N 104.5W Mon afternoon. Gale force winds in the Gulf of Tehuantepec will continue through this evening, then winds will then gradually diminish through the weekend. Moderate to fresh S-SW winds will develop in the Gulf of California north 30N Sat night, and increase to fresh to strong Sat night through Sun morning. Moderate to fresh NW-N winds will develop in the northern Gulf of California Mon morning, shifting southward through Mon night. Elsewhere, gentle to moderate winds and moderate seas will prevail through the weekend into next week. A set of NW swell may propagate into the waters offshore Baja California late Sun into early next week with building seas to around 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh NW-N winds, and seas of 7-10 ft, are beyond 60 nm offshore western Guatemala due to a gap wind event in the Gulf of Tehuantepec. Gentle to moderate NW-N winds are elsewhere north 08N, with moderate S-SW winds south of 08N. Seas are 4-6 ft in S-SW swell. For the forecast, moderate winds well offshore Guatemala and 7-10 ft seas will decrease through the night, while moderate seas will prevail elsewhere. 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 28N132W. A surface trough extends from the low to 27N130W to 23N131W to 21N138W. 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 15N west of 120W with mainly light to gentle winds 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 to locally fresh 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, locally 9 ft near 03.4S, and 4-6 ft east 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 the end of this week. $$ AL