000 AXPZ20 KNHC 211558 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Hurricane Norma is centered near 22.7N 110.3W at 21/1500 UTC, moving north at 7 kt. Estimated minimum central pressure is 968 mb. Maximum sustained wind speed is 85 kt with gusts to 105 kt. Norma is a category 2 on the Saffir Simpson Scale. Peak seas are around 36 ft with the 12 ft seas extending 150 nm NE quadrant, 210 nm SE quadrant, 240 nm SW quadrant and 270 nm NW quadrant. Numerous moderate to strong convection is noted from 22N to 24N between 108W and 111W. Norma will continue to move N through this evening, followed by a turn toward the northeast and east- northeast with a reduction in forward speed tonight through Monday. On the forecast track, the center of Norma is expected to move over the southern portion of Baja California Sur within the hurricane warning area today. Norma is forecast to move toward the west coast of Mexico on Sunday night and move inland within the tropical storm watch area by early Monday. Continued weakening is expected during the next few days, but Norma is expected to remain a hurricane while it moves over the southern portion of Baja California Sur. 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): Shower and thunderstorm activity has increased in association with a broad area of low pressure located several hundred miles south of the Gulf of Tehuantepec. Upper-level winds are expected to become more conducive for development, and a tropical depression is likely to form during the next couple of days. 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 near 11N86W to low pres near 10N97W 1007 mb to 11N114W to 07N130W. The ITCZ then extends from 07N130W to beyond 09N140W. Numerous moderate to isolated strong convection is noted from 04N to 13N between 82W and 94W and from 04N to 12N between 95W and 102W. Scattered moderate convection is noted from 06N to 11N between 107W and 122W. ...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, a ridge extends W of the Baja California offshore waters. Moderate to fresh NW winds prevail in the Baja California offshore waters N of Cabo San Lazaro along with NW swell with seas ranging from 8 to 11 ft. Strong N winds persist across the Gulf of Tehuantepec with seas to 8 ft. Moderate to fresh winds are also likely occurring in the outer offshore waters of Oaxaca due to EP91. In the Gulf of California, light to gentle variable winds continue N of 26N with seas to 3 ft. To the south of 26N, 12 to 20 ft seas are ongoing due to the proximity of Norma. In the remaining SW Mexican offshore waters, winds are light to gentle with seas of 7 to 11 ft in mixed swell due to Norma. For the forecast, Norma will move inland to 23.4N 110.1W this evening, weaken to a tropical storm near 24.1N 109.4W Sun morning, 24.5N 108.6W Sun evening, inland to 24.7N 107.7W Mon morning, move inland and weaken to a tropical depression near 25.1N 106.8W Mon evening, and dissipate Tue morning. Elsewhere, the strong winds over the Gulf of Tehuantepec will diminish this afternoon. Fresh to locally strong winds can be expected across the Baja California offshore waters N of Cabo San Lazaro this weekend along with large NW swell. This will result 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 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 Invest EP91. A broad area of low pressure located well south of the Gulf of Tehuantepec (Invest EP91), is generating moderate SE to E winds across the westernmost portion of the offshore waters of Guatemala and El Salvador. Otherwise, light to gentle winds prevail N of the monsoon trough in the Central American offshore waters. Seas range 5 to 8 ft with the higher seas close to EP91. South of the monsoon trough, gentle to moderate W to SW winds are noted with seas 5 to 7 ft within S to SW swell. Strong thunderstorms with heavy rainfall continues across the Central American offshore waters. For the forecast, light to gentle winds will prevail N of the monsoon trough with gentle to moderate winds S of the monsoon trough through the weekend. Winds will begin to increase to locally moderate across the South America and Galapagos Islands offshore waters briefly early next week. Seas may build slightly in SW swell offshore Ecuador to the Galapagos Islands by the end of the weekend, spreading across the rest of the offshore waters from W to E by early next week as NW swell arrives. EP91 has the potential to develop into a tropical depression during the next couple of days. The system is forecast to meander or drift generally northward through early next week. ...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 20N and W of 119W anchored by a pair of high pres centers. Moderate SW winds are noted in the NW corner of the area ahead of a dissipating stationary front, N of 27N and W of 131W. Light to gentle winds prevail elsewhere across this area N of the monsoon trough and W of 120W. 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 11 ft according to recent altimeter data. Seas of 8 ft or greater covers the majority of the waters between 93W and 130W. 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 tonight through the 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 inland to 23.4N 110.1W this evening, weaken to a tropical storm near 24.1N 109.4W Sun morning, 24.5N 108.6W Sun evening, inland to 24.7N 107.7W Mon morning, move inland and weaken to a tropical depression near 25.1N 106.8W Mon evening, and dissipate Tue morning. Elsewhere, a weak pressure pattern will support mainly gentle to moderate winds across the open waters through the weekend. Winds may increase moderate to locally 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 early next week, potentially building seas to 7-10 ft N of 24N. $$ AReinhart