000 AXPZ20 KNHC 201553 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Oct 20 2023 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Hurricane Norma is centered near 19.4N 109.2W at 20/1500 UTC, moving NNW at 7 kt. Estimated minimum central pressure is 960 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Norma is a category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale. Peak seas are around 36 ft with the 12 ft seas extending within 270 nm of the center except 210 nm in the NE quadrant. Numerous moderate to strong convection is noted from 17N to 22N between 107W and 112W. A NNW to N motion is forecast through Saturday, followed by a turn toward the northeast on Sunday. On the forecast track, Norma is expected to approach the southern portion of Baja California Sur tonight and move near or over the area on Saturday. Norma is forecast to move toward the west coast of mainland Mexico on Sunday and Sunday night. Gradual weakening is expected during the next few days, but Norma is forecast to be a hurricane when it moves near or over the southern portion of Baja California Sur. Swells generated by Norma are affecting portions of the coast of southwestern and west-central Mexico and Baja California Sur. These swells will spread northward along the coast of western Mexico and the Baja California peninsula this 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 HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Norma NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. South of Southern Mexico (EP91): A broad area of low pressure located several hundred miles south of the Gulf of Tehuantepec continues to produce large area of showers and thunderstorms, mainly over the western part of the circulation. This scattered moderate to isolated strong convection is noted from 06N to 1N between 96W and 99W. Upper- level winds are forecast to become more conducive for development later this weekend, and a tropical depression will likely form by early next week. The system is forecast to meander during the next couple of days and then drift generally northward late this weekend and into early next week. This system has a medium chance of tropical cyclone formation through 48 hours, and a high chance through 7 days. Please read the latest NHC Tropical Weather Outlook at www.hurricanes.gov for details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 10N86W to low pressure (EP91) near 09N96W 1007 mb to 23N101W, then resumes near 13N112W to low pres near 20N121W 1008 mb to 07N130W to 11N140W. Scattered moderate isolated strong noted from 02N to 10N between 78W and 93W. Scattered moderate convection is noted from 06N to 13N between 110W and 124W and from 07N to 12N and W of 133W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norma, and on low pressure (EP91) near 08N95W. Hurricane Norma is centered near 18.8N 108.6W at 20/0900 UTC, moving north-northwest at 6 kt. Estimated minimum central pressure is 955 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Aside from Hurricane Norma, a ridge extends W of the Baja California offshore waters. Fresh to strong winds prevail in the Gulf of Tehuantepec. Gentle to moderate winds prevail across the remainder of the offshore waters. Seas are in the 7-10 ft range in NW swell offshore Baja California Norte, and 4-7 ft elsewhere over the open waters off Mexico. Seas of 1-3 ft are ongoing over the Gulf of California, however building near the entrance due to Norma. For the forecast, other than the low pressure area (EP91) near 08N95W, Norma will move to 19.7N 109.2W this afternoon, 21.2N 109.7W Sat morning, 22.4N 109.6W Sat afternoon, weaken to a tropical storm near 23.3N 109.2W Sun morning, 23.6N 108.4W Sun afternoon, and 23.9N 107.8W Mon morning. Norma will weaken to a tropical depression while moving inland near 25.3N 106.6W early Tue. Elsewhere, fresh to strong N winds will continue to pulse over the Tehuantepec region through Sat morning. Gentle to moderate winds will prevail elsewhere through the end of the week, except fresh to locally strong offshore Baja California this weekend. Large NW swell is forecast to continue to spread offshore Baja California into the weekend, resulting in confused and hazardous seas as it mixes with swells generated by Norma. A new set of NW swell may spread offshore Baja California early next week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the SPECIAL FEATURES section above for more details on low pressure (EP91) near 08N95W. Gentle to moderate gap winds are over the Papagayo region N of the monsoon trough and E of 88W. Gentle to moderate winds are elsewhere S of the monsoon trough. Seas are in the 3-6 ft range across the region. Heavy showers and thunderstorms are offshore Colombia and Panama as detailed above. For the forecast, other than the low pressure area (EP91), light to gentle winds will prevail north of the monsoon trough in the Papagayo region through the weekend. Gentle to moderate winds will prevail south of the monsoon trough, except fresh to strong just offshore Costa Rica and Panama Sat and Sat night. Seas may build slightly in SW swell offshore Ecuador to the Galapagos Islands today, then build slightly across the waters from W to E by the end of the weekend as NW swell arrives. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norm and low pressure (EP91) near 08N95W. A weak trough extends from 17N124W to 25N125W, and a weak 1010 mb area of low pressure is embedded in the monsoon trough near 10N122W. Otherwise, ridging dominates the waters N of the monsoon trough. Mainly light to gentle winds are N of 20N, with gentle to moderate winds elsewhere over the open waters. Large NW swell is propagating across the NW waters. Peak seas are currently around 11 ft. Seas of 8 ft or greater will continue to propagate SE, and will cover the majority of the waters W of 100W today. Confused and hazardous seas will result from the combination of the NW swell, SW swell moving N of the Equator, and swells generated by Norma through the end of the week and into the weekend. Seas will gradually decay from west to east Fri night through the upcoming weekend. Please read the latest NHC High Seas Forecast at website www.hurricanes.gov/marine for more details. For the forecast, other than the large NW swell event and low pressure (EP91), Norma will move to 19.7N 109.2W this afternoon, 21.2N 109.7W Sat morning, 22.4N 109.6W Sat afternoon, weaken to a tropical storm near 23.3N 109.2W Sun morning, 23.6N 108.4W Sun afternoon, and 23.9N 107.8W Mon morning. Norma will weaken to a tropical depression while moving inland near 25.3N 106.6W early Tue. Elsewhere, a weak pressure pattern will support mainly gentle to moderate winds across the open waters through the weekend. Winds may increase slightly early next week as high pressure builds N of the area and tightens the pressure gradient. Meanwhile, a new set of NW swell generated offshore California, is forecast to spread S of 30N to the E of 130W by early next week, potentially building seas to 7-10 ft N of 24N. $$ AKR