000 AXPZ20 KNHC 200400 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Oct 20 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 0350 UTC. ...SPECIAL FEATURES... Major Hurricane Norma is centered near 18.2N 108.1W at 20/0300 UTC, moving north at 6 kt. Estimated minimum central pressure is 948 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Peak seas are currently around 39 ft. Numerous moderate to strong convection is noted within 180 nm NE and 150 nm SW semicircle of the center. On the forecast track, Norma is forecast to approach the southern portion of Baja California on Friday night and Saturday. Some weakening is expected during the next few days, but Norma is forecast to be a hurricane when it moves near the southern portion of Baja California. 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. South of Southern Mexico (EP91): A broad 1007 mb area of low pressure located several hundred nautical miles south of the Gulf of Tehuantepec near 08N95W continues to produce a large area of disorganized showers and thunderstorms from 04N to 12N between 92W and 100W. Gradual development of this system is expected, and a tropical depression is likely to form during the next few days while the system meanders or drifts generally northward over the far eastern portion of the basin. 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 10N85W to low pressure (EP91) near 08N95W to 11N100W, then resumes well SW of Norma near 12N113W to low pressure near 10N122W to 06N130W to 10N140W. Scattered moderate isolated strong convection is noted from 02N to 10N between 77W and 92W, and from 06N to 12N between 104W and 113W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norma, and on low pressure (EP91) near 08N95W. Hurricane Norma is centered near 18.2N 108.1W at 20/0300 UTC, moving north at 6 kt. Estimated minimum central pressure is 948 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Aside from Hurricane Norma, a ridge extends W of the Baja California offshore waters. Fresh to strong winds prevail in the Gulf of Tehuantepec. Gentle to moderate winds prevail across the remainder of the offshore waters. Seas are in the 7-10 ft range in NW swell offshore Baja California Norte, and 4-7 ft elsewhere over the open waters off Mexico. Seas of 1-3 ft are ongoing over the Gulf of California, however building near the entrance due to Norma. For the forecast, other than the low pressure area (EP91) near 08N95W, Norma will move to 19.2N 108.6W Fri morning, 20.6N 109.2W Fri evening, 22.1N 109.5W Sat morning, 23.2N 109.4W Sat evening, weaken to a tropical storm near 23.8N 109.0W Sun morning, and 24.4N 108.1W Sun evening. Norma will weaken to a tropical depression while moving inland near 25.3N 106.5W late Mon. Elsewhere, fresh to strong N winds will continue to pulse over the Tehuantepec region through Sat morning. Gentle to moderate winds will prevail elsewhere through the end of the week, except fresh to locally strong offshore Baja California this weekend. Large NW swell is forecast to continue to spread offshore Baja California 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. ...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 low pressure (EP91) near 08N95W. Gentle to moderate gap winds are over the Papagayo region N of the monsoon trough and E of 88W. Gentle to moderate winds are elsewhere S of the monsoon trough, except for locally fresh S winds W of 88W in the region of Papagayo and off Machala, Ecuador. Seas are in the 3-6 ft range across the region. Heavy showers and thunderstorms are offshore Colombia and Panama as detailed above. For the forecast, other than the low pressure area (EP91), light to gentle winds will prevail north of the monsoon trough in the Papagayo region through the weekend. Gentle to moderate winds will prevail south of the monsoon trough, except fresh to strong just offshore Costa Rica and Panama Sat and Sat night. Seas may build slightly in SW swell offshore Ecuador to the Galapagos Islands Fri, then build slightly across the waters from W to E by the end of the weekend as NW swell arrives. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on Major Hurricane Norm and low pressure (EP91) near 08N95W. A weak trough extends from 18N124W to 24N125W, and a weak 1010 mb area of low pressure is embedded in the monsoon trough near 10N122W. Otherwise, ridging dominates the waters N of the monsoon trough. Mainly light to gentle winds are N of 20N, with gentle to moderate winds elsewhere over the open waters. Large NW swell is propagating across the NW waters. Peak seas are currently around 10 ft. Seas of 8 ft or greater will continue to propagate SE, and will cover the majority of the waters W of 100W by early Fri. 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 Fri night through the upcoming 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 19.2N 108.6W Fri morning, 20.6N 109.2W Fri evening, 22.1N 109.5W Sat morning, 23.2N 109.4W Sat evening, weaken to a tropical storm near 23.8N 109.0W Sun morning, and 24.4N 108.1W Sun evening. Norma will weaken to a tropical depression while moving inland near 25.3N 106.5W late Mon. Elsewhere, 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 7-10 ft N of 24N. $$ Ramos