000 AXPZ20 KNHC 252157 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Sep 25 2024 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 2130 UTC. ...SPECIAL FEATURES... Tropical Storm John is centered near 16.8N 101.5W at 25/2100 UTC, moving north at 3 kt. Estimated minimum central pressure is 996 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Seas of 12 ft or greater are occurring within 240 NM in the SE quadrant and 210 NM in the SW quadrant with peak seas near 16 ft. Convection is becoming increasingly organized around the center of John, with strong convection occurring within 75 NM to the east, south and north of the center, and within 150 NM to the west. John is forecast to strengthen as it approaches the coast of southern Mexico on Thursday. John will move to 17.1N 101.5W Thu morning, strengthen to a hurricane near 17.5N 101.5W Thu afternoon, move inland and weaken to a tropical storm near 18.0N 101.6W Fri morning, move inland and weaken to a tropical depression near 18.2N 102.1W Fri afternoon, and dissipate Sat morning. Through Friday, Tropical Storm John is expected to produce additional rainfall amounts of 10 to 20 inches with isolated totals around 30 inches across portions of the Mexican States of Guerrero, Oaxaca and Michoacan. A dangerous storm surge is expected to produce coastal flooding near and to the east of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. 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 John NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A Central American Gyre will continue to produce periods of excessive rainfall over southern Mexico and Central America for the remainder of the week, as well as the adjacent western Caribbean and eastern Pacific waters between 80W and 95W. This scenario, combined with daytime heating and orographic lifting, could produce dangerous flash flooding and mudslides across the area. Furthermore, strong to near gale force winds, rough seas and heavy thunderstorms are forecast to affect the offshore waters between Costa Rica and Guatemala through the end of the week. Please follow the forecasts from your local weather offices for more detailed information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 13N110W to beyond 09N140W. Aside from the convection related to Tropical Storm John and the Central American Gyre, scattered moderate to locally strong convection is occurring from 11N to 14N between 112W and 118W, and from 09N to 11N between 129W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for information on Tropical Storm John and on the Central American Gyre (CAG). A 1005mb low pressure is centered near 34N114W and troughing extends through the Gulf of California toward Tropical Storm John. This pattern supports moderate to fresh NW winds and seas of 4-7 ft across much of the Mexico offshore waters. Light to gentle breezes and seas of 1-3 ft prevail in the Gulf of California. Farther south, south of 18N and east of 105W, strong to near gale force winds are occurring along the periphery of Tropical Storm John, as confirmed by a recent scatterometer pass. A recent altimeter pass portrayed seas of 9 to 15 ft associated with these winds. For the forecast away from the direct impacts from Tropical Storm John, strong to near gale force winds will continue south of 18N and east of 106W into early Fri. Winds will slowly diminish below strong speeds Fri night, diminishing further on Sat. Rough to very rough seas will accompany these winds through late Fri before slowly subsiding Sat into Sun. Elsewhere, mostly fresh northwest winds and moderate to locally rough seas will occur across the remainder of the Mexican offshore waters through Sat, with the exception of the Gulf of California, where winds will remain light to gentle. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please refer to the Special Features section above for information on the Central American Gyre (CAG). Moderate to fresh SW winds are occurring over the coastal waters from Guatemala through Nicaragua, and seas of 6-10 ft are noted in this area. Gentle to moderate S to SW winds and seas of 4-7 ft prevail elsewhere. Scattered moderate to locally strong convection is noted north of 11N between 88W and 94W, with similar convection noted north of 04N and east of 86W toward Panama and Colombia. Strong winds and rough seas will occur near convection. For the forecast, moderate to fresh SW winds will continue across the offshore waters of Nicaragua tonight, and persist across the waters of El Salvador and Guatemala through Fri. Moderate to rough seas will accompany these winds, with seas slowly subsiding this weekend. Elsewhere, gentle to moderate SW winds will continue into early next week. Scattered to numerous showers and thunderstorms will continue over most of the offshore waters through the rest of the week. ...REMAINDER OF THE AREA... A recent scatterometer pass revealed strong to near gale force winds along the periphery of Tropical Storm John, generally north of 10N and east of 109W. Seas of 9 to 13 ft are likely occurring in this region. Moderate to locally fresh SW winds are noted south of the monsoon trough east of 120W and north of 09N. Elsewhere, gentle to moderate N to NE winds prevail north of the monsoon trough with seas of 4-7 ft. For the forecast, strong to near gale force winds will continue north of 09N and east of 114W through Fri before winds slowly diminish through Sat. Rough to locally very rough seas will accompany these winds, with seas slowly subsiding this weekend into early next week. Elsewhere, a building NW swell will lead to seas of 8 to 9 ft north of 22N and west of 126W tonight through Thu. $$ ADAMS