000 AXPZ20 KNHC 211003 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0950 UTC. ...SPECIAL FEATURES... Major Hurricane Norma is centered near 21.7N 110.1W at 21/0900 UTC, moving north at 8 kt. Estimated minimum central pressure is 958 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Peak seas are up to 38 ft. Numerous moderate to strong convection is noted from 21N to 24N between 108W and 111W. Scattered moderate convection is elsewhere from 18N to 28N between 105W and 114W. 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 later today. Norma is forecast to move toward the west coast of Mexico on Sunday night and move inland within the tropical storm watch area on Monday. Continued gradual 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. 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 is producing limited shower activity due to unfavorable upper-level winds. Environmental conditions, however, 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 during the next couple of days and then drift generally northward by 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 pres near 09N96W 1007 mb to 10N105W, then resumes well SW of Norma near 09N124W to 07N130W. The ITCZ continues from that point to 11N140W. Numerous moderate to strong convection is from 07N to 11N between 96W and 102W. Scattered moderate to strong convection is noted from 00N to 13N E of 94W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norma and Invest EP91. Aside from Hurricane Norma, a ridge extends W of the Baja California offshore waters. Gentle to moderate 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. A plume of strong winds prevails across the Gulf of Tehuantepec with seas to 8 ft. In the Gulf of California, light to gentle variable winds continue N of 26N with seas to 3 ft. To the south of 26N, 5 to 14 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 to 22.7N 110.1W this afternoon, inland to 23.5N 109.7W Sun morning, 23.9N 109.0W Sun afternoon, weaken to a tropical storm near 24.2N 108.1W Mon morning, inland to 24.7N 107.0W Mon afternoon, and 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 offshore Colombia, Panama, and Costa Rica. 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 later this weekend or 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. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on Major 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 28N and W of 138W. 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 10 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 to 22.7N 110.1W this afternoon, inland to 23.5N 109.7W Sun morning, 23.9N 109.0W Sun afternoon, weaken to a tropical storm near 24.2N 108.1W Mon morning, inland to 24.7N 107.0W Mon afternoon, and 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. $$ Ramos