000 AXPZ20 KNHC 190307 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Oct 18 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Hurricane Norma is centered near 16.4N 108.0W at 19/0300 UTC, moving north at 7 kt. Estimated minimum central pressure is 975 mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt. Peak seas are currently around 25 ft. Numerous moderate scattered strong convection is noted within 90 nm of the center of Norma. Scattered moderate and isolated strong convection is elsewhere from 08N to 22N between 100W and 112W. Continued rapid strengthening is forecast through tonight, and Norma could become a major hurricane on Thursday. 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 of 12 ft or greater have reached roughly N of 22N and W of 132W per with seas likely peaking around 14 ft. Seas of around 12 ft or greater will continue to spread SE to cover much of the waters N of 20N and W of 130W through early Thu. Seas of 8 ft or greater 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 be the result of 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 08N94.5W to 10N100W, then resumes SW of Norma near 11N115W to 08N130W to 09N140W. Scattered moderate isolated strong convection is noted from 04N to 11N between 85W and 100W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Hurricane Norma. Fresh to strong winds prevail in the Gulf of Tehuantepec, with seas to 8 ft. Aside Hurricane Norma, a ridge extends across the Baja California offshore waters. Gentle to moderate winds prevail west of the Baja California peninsula with light to gentle winds 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 1-2 ft are noted over the Gulf of California. For the forecast, Hurricane Norma is near 16.4N 108.0W at 8 PM PDT, and is moving north at 7 kt. Maximum sustained winds are 80 kt with gusts to 100 kt, and the minimum central pressure is 975 mb. Norma will move to 17.2N 108.1W Thu morning, 18.3N 108.4W Thu evening, 19.3N 108.9W Fri morning, 20.6N 109.5W Fri evening, 22.1N 109.8W Sat morning, and 23.0N 109.8W Sat evening. Norma will weaken to a tropical storm near 23.5N 109.5W late Sun. 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 a few disorganized showers and thunderstorms. Any development of this system during the next couple of days is expected to be slow to occur. However, environmental conditions are expected to become more favorable for development thereafter, and a tropical depression is likely to form over the weekend or early next week. The disturbance is forecast to meander for the next several days and then drift northward or northwestward starting on Sunday or Monday. 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... Moderate to fresh 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, moderate seas from swell generated by a Gulf of Tehuantepec gap wind event will subside offshore Guatemala tonight. Winds will pulse moderate to fresh near the Gulf of Papagayo through Thu morning. 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 a few disorganized showers and thunderstorms. Any development of this system during the next couple of days is expected to be slow to occur. However, environmental conditions are expected to become more favorable for development thereafter, and a tropical depression is likely to form over the weekend or early next week. The disturbance is forecast to meander for the next several days and then drift northward or northwestward starting on Sunday or Monday. 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, mainly gentle to moderate winds under a weak pressure pattern will prevail elsewhere 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, fresh 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