000 AXPZ20 KNHC 190917 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Oct 19 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... Major Hurricane Norma is centered near 16.7N 107.7W at 19/0900 UTC, moving north at 5 kt. Estimated minimum central pressure is 953 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Peak seas are currently around 30 ft. Numerous moderate scattered strong convection is noted within 120 nm of the center of Norma. Scattered moderate and isolated strong convection is elsewhere from 09N to 21N between 101W and 111W. Norma is now a category 3 hurricane and is likely nearing is peak intensity, with slight strengthening forecast today before beginning a weakening trend. The center of Norma is forecast to reach the southern tip of the Baja California peninsula in a few days. Heavy rainfall from Norma will begin to impact the far southern portions of Baja California Sur late Friday, continuing through Sunday. This rainfall may produce flash and urban flooding, along with possible mudslides in areas of high terrain. Swells generated by Norma are affecting portions of the coast of southwestern Mexico, and will spread northward along the coast of western Mexico and toward Baja California Sur during the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. Interests in Baja California Sur should monitor the progress of Norma. 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. NW Swell in the NW waters: Large NW swell is propagating across the NW waters. Seas have started to subside, with peak seas estimated to be near 13 ft N of 25N and W of 135W. Seas of 8 ft or greater will continue to propagate SE, and will cover the majority of the waters W of 100W by the end of the week. By that time, peak seas should subside to just below 12 ft. 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 by the end of the week. 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09.5N84W to low pressure near 08.5N94.5W to 10N100W, then resumes SW of Norma near 11N115W to 07N132W to 09N140W. Scattered moderate isolated strong convection is noted from 03N to 12N between 86W and 100W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norma. Fresh to strong winds prevail in the Gulf of Tehuantepec, with seas to 8 ft. Aside from Hurricane Norma, a ridge extends across the Baja California offshore waters. Gentle to moderate winds prevail west of the Baja California peninsula as well as the Gulf of California. Light to gentle winds are elsewhere offshore Mexico. Seas are in the 6-8 ft range offshore Baja California Norte, and 4-7 ft elsewhere over the open waters off Mexico. Seas of 1-3 ft are noted over the Gulf of California. For the forecast, Major Hurricane Norma is near 16.7N 107.7W at 2 AM PDT, and is moving north at 5 kt. Maximum sustained winds are 105 kt with gusts to 130 kt, and the minimum central pressure is 953 mb. Norma will move to 17.5N 108.1W this afternoon, 18.6N 108.5W Fri morning, 19.8N 109.1W Fri afternoon, 21.2N 109.6W Sat morning, 22.3N 109.6W Sat afternoon, and weaken to a tropical storm near 23.0N 109.7W Sun morning. Norma will change little in intensity as it moves to near 23.4N 109.3W early Mon. Elsewhere, fresh to strong N winds will continue to pulse over the Tehuantepec region through the remainder of the week. Gentle to moderate winds will prevail elsewhere through the end of the week. Fresh to strong winds offshore Baja California may develop this weekend. Large NW swell is forecast to spread offshore Baja California by the end of the week 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. Meanwhile, a weak area of low pressure located several hundred miles south of the Gulf of Tehuantepec is producing some disorganized showers and thunderstorms. Gradual development is expected, and a tropical depression is likely to form over the weekend or early next week while the system meanders or drifts generally northward over the far eastern portion of the basin. This system has a low chance of tropical cyclone formation through 48 hours, and a high chance through 7 days. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate gap winds are over the Papagayo region, extending downstream of Papagayo to near 10N95W. Light to gentle winds are noted elsewhere N of the monsoon trough. Gentle to moderate winds are S of the monsoon trough. Seas are in the 5-7 ft range well offshore Guatemala, 4-6 ft over and downstream of the Gulf of Papagayo, and 3-5 ft elsewhere across the discussion waters. For the forecast, gentle to moderate winds over and downstream of Papagayo will diminish today, with light to gentle winds then prevailing north of the monsoon trough through the weekend. Gentle to moderate winds will prevail south of the monsoon trough. Seas may build slightly in SW swell offshore Ecuador to the Galapagos Islands by the end of the week into the weekend, then build slightly across the waters from W to E by the end of the weekend as NW swell arrives. Meanwhile, a weak area of low pressure located several hundred miles south of the Gulf of Tehuantepec is producing some disorganized showers and thunderstorms. Gradual development is expected, and a tropical depression is likely to form over the weekend or early next week while the system meanders or drifts generally northward over the far eastern portion of the basin. This system has a low chance of tropical cyclone formation through 48 hours, and a high chance through 7 days. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on newly upgraded Hurricane Norma, and for details on a large NW swell event over the NW waters. Ridging dominates the waters N of the monsoon trough. Light winds are over the far NW waters. Gentle to moderate winds are elsewhere over the discussion waters. Other than the NW swell described above, seas of 5-7 ft prevail, reaching to around 8 ft S of the Equator to 03.4S and W of 110W. For the forecast, other than the large NW swell event, 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 7-11 ft N of 25N. $$ AL