000 AXNT20 KNHC 032355 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Nov 4 2024 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2330 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Eighteen (PTC-18): Potential Tropical Cyclone Eighteen is centered near 13.0N 77.1W at 03/2100 UTC or 300 nm S of Kingston Jamaica, moving NE at 6 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Moderate to strong convection is occurring from 11N to 13N between 75W and 79W, mainly to the south of the center. Seas of 8 to 11 ft are noted from 12N to 16N between 73W and 79W. This system is expected to become a tropical depression tonight and steady strengthening is forecast. Eighteen will move to 14.3N 77.1W Mon morning, 16.0N 77.7W Mon afternoon, 17.7N 78.6W Tue morning, 19.6N 80.4W Tue afternoon, 21.5N 82.6W Wed morning, and 23.3N 84.5W Wed afternoon. Eighteen will change little in intensity as it moves to 25.4N 86.6W Thu afternoon. Heavy rainfall will impact areas of the western Caribbean with the heaviest rainfall occurring over Jamaica and southern Cuba through mid-week. Rainfall totals between 3 to 6 inches with locally up to 9 inches are expected. Flooding could occur over portions of Jamaica and Cuba, with mudslides possible. Heavy rainfall will spread north into Florida and adjacent areas of the Southeast United States mid to late week. Swells generated by the system are expected to affect much of the western Caribbean during the next few days. Please consult products from your local weather office. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Eighteen NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Atlantic Significant Swell: Wind waves produced by strong to near-gale force ENE winds along with large easterly swell will continue to produce 12 to 14 ft seas from 22N to 27N between the southeast and central Bahamas and 66W through Mon morning. Very rough seas will move northward Mon afternoon, reaching 25N to 30N. Starting Tue evening, both winds and seas should gradually subside. Please see the latest High Seas and Offshore Waters Forecast issued by the National Hurricane Center at website https//www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https//www.nhc.noaa.gov/marine/offshores.php for more information. Central America and Northwestern Colombia Heavy Rainfall: Robust moisture related to the Central American Gyre and newly formed Potential Tropical Cyclone Eighteen will lead to enhanced heavy rainfall across Costa Rica, Panama and the coastal areas of northwestern Colombia. This will increase the potential for flash flooding and mudslides. Please monitor this developing situation and refer to your local weather service for more information. ...TROPICAL WAVES... A tropical wave in the central Atlantic is near 49W from 13N southward, and moving westward 10 to 15 kt. Scattered moderate to locally strong convection is noted from 05N to 13N between 36W and 52W. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near 11N16W then extends southwestward to 08N19W. The ITCZ then extends from 08N19W to 11N47W, then resumes near 10N51W to 10N58W. Scattered moderate to locally strong convection is noted south of 08N between 19W and 28W. ...GULF OF MEXICO... Surface ridging prevails across much of the Gulf of Mexico. Winds have veered to the SE off the coast of Texas, with fresh to locally strong SE winds occurring north of 24N and west of 93W ahead of a developing cold front in the Southern Plains. A tightening pressure gradient between the ridge and the strengthening PTC-18 supports fresh to locally strong E to NE winds and seas of 4 to 7 across the Straits of Florida into southeastern portions of the Gulf. Moderate to locally fresh SE winds and seas of 3 to 6 ft are noted across most of the rest of the basin, except in the Bay of Campeche, where gentle winds and slight seas prevail. For the forecast, fresh SE winds across the northwestern Gulf will become strong tonight into Tue as a cold front slowly approaches eastern Texas. Fresh to locally strong E winds and rough seas will continue in the Straits of Florida late tonight, and fresh to strong E winds will occur over much of the eastern Gulf east of 87W Mon night through Tue as PTC-18 moves northward through the Caribbean. Looking ahead, although there remains uncertainty with development and track of PTC-18, expect strong winds and rough seas across much of the eastern Gulf Wed through late week. ...CARIBBEAN SEA... Please refer to the SPECIAL FEATURES section for information regarding about PTC-18 and the threat for heavy rainfall across Central America and the Caribbean Sea. An upper-level trough curves southeastward from a low just north of Puerto Rico across the Lesser Antilles. These features are leading to widely scattered showers and isolated thunderstorms across northeastern through central portions of the basin. A surface trough south of the Yucatan Channel is leading to widely scattered showers and thunderstorms from the Gulf of Honduras eastward to near Jamaica. Outside the influence of PTC-18, fresh to strong NE winds and locally rough seas are occurring downwind of Cuba in the northwestern Caribbean. Otherwise, gentle to moderate NW to NE to SE winds with 3 to 5 ft seas are present across the southwestern, central and eastern basin. For the forecast, the pressure gradient between a strong high pressure ridge north of the area and lower pressure over the southwestern basin will support fresh to strong NE to E winds in the lee of Cuba and the Windward Passage through Mon. PTC-18 is expected to move near Jamaica by late Monday and near or over the Cayman Islands Tuesday and Wednesday. This system is expected to become a tropical depression tonight and steady strengthening is forecast. Away from the impacts from PTC-18, moderate to locally fresh E to NE winds and slight to moderate seas will occur across eastern portions of the basin through the forecast period. ...ATLANTIC OCEAN... Please refer to the SPECIAL FEATURES section for information regarding the significant swell across the western Atlantic. Troughing extends from near Madeira to 20N35W, and a stationary front extends from 20N35W to a a 1010 mb low east of the Turks and Caicos Islands. Patchy showers are seen up to 50 nm along either side of this boundary east of 50W. West of 50W, scattered showers and isolated thunderstorms are occurring up to 100 nm along either side of this boundary and low pressure. Outside the Significant Swell area mentioned in the Special Features section, fresh to strong NE winds and seas of 5 to 8 ft are present north of 26N between 65W and the east coast of Florida. Gentle to moderate with locally fresh E to SE winds and 7 to 10 ft seas in large N swell exist north of 20N between 40W and 60W. To the south from the Equator to 20N/22N between 35W and the Lesser Antilles, gentle to moderate with locally fresh NE to SE winds and seas at 6 to 8 ft in large mixed swells prevail. For the forecast W of 55W, a strong cold front is expected to move southeastward through the central and western Atlantic Mon through the middle of this week, leading to widespread fresh to strong NE to E winds north of 27N on Mon and north of 23N by Tue. Rough to very rough seas are expected across this region in mixed N to NE swell. For areas south of 20N, moderate E trades and moderate seas will prevail through midweek, with the N swell leading to rough seas late in the week. $$ ADAMS