000 AXPZ20 KNHC 212140 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Oct 21 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Hurricane Norma is centered near 23.1N 110.0W at 21/2100 UTC, moving north-northeast at 5 kt. Estimated minimum central pressure is 979 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Norma is a category 1 on the Saffir Simpson Scale. Peak seas are around 31 ft. Scattered moderate to isolated strong convection is noted from 22N to 26N between 107W and 111W. Norma will continue moving NNE through tonight, followed by a turn toward the NE and ENE on Sunday and Sunday night. On the forecast track, the center of Norma is expected to move across the southern portion of Baja California Sur tonight. Norma is forecast to move toward the west coast of Mexico on Sunday and move inland within the tropical storm warning area on Sunday night or early Monday. Continued weakening is expected during the next couple of days, and Norma is expected to approach the west coast of Mexico as a tropical storm. Swells generated by Norma will continue to affect the coast of southwestern and west- central Mexico and Baja California Sur for 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 and 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 a large area of shower and thunderstorm activity. The upper-level winds are expected to become more conducive for development of this system during the next couple of days, and a tropical depression is likely to form by early next week. The system is forecast to meander or drift generally northward through early next week. This system has a high chance of tropical cyclone formation through 48 hours. 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/Nicaragua border near 11N86W to low pres near 10N97W 1007 mb to 11N115W to 07N128W. The ITCZ extends from 07N128W to beyond 07N140W. Scattered moderate to isolated strong convection from 06N to 12N between 95W and 102W. Scattered moderate convection is from 04N to 12N between 78W and 93W and from 05N to 12N between 104W and 123W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Hurricane Norma and Invest EP91. Aside from Hurricane Norma, ridging across the Baja California offshores is sliding westward due to Norma moving across Baja California Sur. Moderate to fresh NW winds prevail north of Cabo San Lazaro. NW swell persists across the offshores with seas 8 to 11 ft. In the Gulf of California, light to gentle winds prevail N of 27N with seas to 4 ft. EP91 is producing moderate to locally fresh winds in the southern portions of the Oaxaca offshore waters with seas to 8 ft. Across the rest of southern Mexico offshores, gentle to moderate winds prevail with 7 to 10 ft seas in mixed swell. For the forecast, Norma will move inland and weaken to a tropical storm near 23.7N 109.9W Sun morning, 24.5N 109.1W Sun afternoon, 24.8N 108.3W Mon morning, move inland and weaken to a tropical depression near 25.1N 107.5W Mon afternoon, and dissipate Tue morning. Elsewhere, fresh to locally strong winds can be expected across the Baja California offshore waters N of Cabo San Lazaro through Mon night. The NW swell across the Baja California offshores is resulting in confused and hazardous seas as it mixes with swells generated by Norma. The swell will begin to subside by Sunday, with a new set of NW swell entering the offshores of Baja California by Mon night into Tue. ...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 Invest EP91. The broad low pressure is located well south of the Gulf of Tehuantepec (EP91). This is resulting in moderate E to SE winds across the westernmost portion of the offshore waters of Guatemala and El Salvador. Otherwise, light to gentle winds are noted north of the monsoon trough. South of the monsoon trough, gentle to moderate S winds prevail. Seas range 5 to 8 ft across the offshore waters with the higher seas closer to EP91. Scattered thunderstorms continue across the Central American offshore waters and off the Colombia coast. For the forecast, winds will begin to increase to locally fresh across the South America and Galapagos Islands offshore waters briefly on Mon. Mixed swell may build slightly in offshore Galapagos Islands to Ecuador by Sun night. NW swell will bring seas up to 8 ft west of the Galapagos Islands later on Sun, with SW swell increasing seas to 7 ft in the Ecuador and portions of Central American offshores through Mon. Seas will subside by mid- week. EP91 has the potential to develop into a tropical depression by early next week. The system is forecast to meander or drift generally northward through early next week. Expect moderate to locally fresh winds and seas to 8 ft in the Guatemala and El Salvador offshore waters the next few days. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on Hurricane Norma and Invest EP91. Surface ridging extends across the northern forecast waters, N of 15N and W of 123W anchored by 1018 high pres near 28N129W. Moderate to locally fresh NW winds prevail N of 18N and E of 123W. Otherwise, gentle to moderate winds are present N of the monsoon trough. S of the monsoon trough, gentle to moderate S to SW winds are noted. Large NW swell continues to propagate across most of the waters. Peak seas are around 10 ft. Seas of 8 ft or greater covers the majority of the waters between 93W and 135W. 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 rest of the weekend. Seas will gradually decay from west to east tonight through early next week. 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 inland and weaken to a tropical storm near 23.7N 109.9W Sun morning, 24.5N 109.1W Sun afternoon, 24.8N 108.3W Mon morning, move inland and weaken to a tropical depression near 25.1N 107.5W Mon afternoon, and dissipate Tue morning. Elsewhere, a weak pressure pattern will support mainly gentle to moderate winds across the open waters through Sun. Winds may increase moderate to fresh by early next week as high pressure builds N of the area and tightens the pressure gradient. Meanwhile, a new set of NW swell is forecast to spread S of 30N to the E of 130W by Mon night into Tue, potentially building seas to 7-10 ft N of 25N. $$ AReinhart