000 AXNT20 KNHC 121815 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Sep 12 2021 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... Newly formed Tropical Storm Nicholas is centered near 20.5N 94.8W at 12/1500 UTC or 115 nm NE of Veracruz Mexico, and moving NNW at 11 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained winds are 35 kt with gusts to 45 kt. Seas are peaking at 8 to 10 ft near the center. Numerous moderate to strong convection is present near and N of the center from 19N to 24N between 92W and 97W. Nicholas is expected to continue on a NNW track through tonight, then slowly turn toward the N or NNE late Monday. This will bring Nicholas very close to the coast of NE Mexico and S Texas late Monday, before approaching S or central Texas Monday night or early Tuesday. Nicholas is forecast to gradually strengthen over the couple of days. Rainfall of 3 to 5 inches are possible near the Mexico-Texas border, and 6 to 10 inches from Corpus Christi northeastward through Houston to Lake Charles. This will increase the chance of flooding at urban and low-lying areas, and near rivers and streams. Please read the latest High Sea Forecast issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Nicholas NHC Forecast/Advisory and Public Advisory at website - www.nhc.noaa.gov/graphics_at4.shtml?start#contents ...TROPICAL WAVES... An Atlantic tropical wave is along 27W from 21N southward and moving W at 15 to 20 kt. Scattered moderate convection is noted from 06N to 10N between 23W and 31W. Another Atlantic tropical wave is near 49W from 22N southward and moving W near 15 kt. Much drier air at mid levels are hindering any significant convection near this wave. A Caribbean tropical wave is along 69W from 21N southward across the E Dominican Republic to NW Venezuela, and moving W at 15 to 20 kt. Enhanced by an upper-level low N of the Dominican Republic near 21N69W, scattered showers and isolated thunderstorms are occurring over the E Dominican Republic and N central Caribbean Basin. A former Caribbean tropical wave is now over the E parts of Honduras and Nicaragua across Costa Rica into the E Pacific, and moving W at 10 to 15 kt. Scattered showers and isolated thunderstorms are evident over central and S Nicaragua. ...MONSOON TROUGH/ITCZ... A monsoon trough passes through the Gambia coast near 13N16W through a 1010 mb low near the Cabo Verde Islands at 17N25W to 13N35W. The ITCZ is seen farther SW from 06N37W to 06N47W. Scattered moderate convection is found near and NE of the low from 17N to 22N between 20W and 26W, and near the monsoon trough from 05N to 15N between the African coast and 18W. Scattered showers and a few thunderstorms are present near the ITCZ from 05N to 08N between 37W and 42W. The National Hurricane Center is monitoring this low and it has a low chance of development over the next 48 hours. The eastern end of the E Pacific monsoon trough is triggering scattered showers and isolated thunderstorms across Panama and the SW Caribbean Basin. ...GULF OF MEXICO... Refer to the Special Features section above for details on newly developed Tropical Storm Nicholas over the SW Gulf. A surface trough curves northeastward across the NW Gulf from 25N96W to just S of the Louisiana coast at 29N93W. Scattered showers and isolated thunderstorms are noted N of 24N between 88W and Mexico-Texas coast. Moderate to fresh SE winds and seas at 4 to 6 ft are seen across the area. Convergent ESE trades are causing similar conditions near the Florida Keys, including the Straits of Florida. Fresh to strong SE winds and seas of 6 to 8 ft are evident over the central and S central Gulf. Gentle to moderate ESE winds and seas at 2 to 4 ft prevail for the rest of the Gulf. For the forecast, Tropical Storm Nicholas is near 20.5N 94.8W 1008 mb at 15 UTC and moving NNW at 11 kt. Maximum sustained winds are 35 kt with gusts to 45 kt. Nicholas will move to 21.9N 95.7W this evening, 24.1N 96.6W Mon morning, 26.4N 96.9W Mon evening, 28.2N 96.5W Tue morning, inland to 29.4N 95.9W Tue evening, and move inland and weaken to a tropical depression near 30.3N 95.2W Wed morning. Nicholas will move inland near 31.0N 94.8W by early Thu. ...CARIBBEAN SEA... Please see the Tropical Waves and Monsoon Trough/ITCZ sections above for convection in the Caribbean Basin. Moderate to fresh trades and sea of 4 to 6 ft are found over the W and central basin. Mainly gentle trades and seas at 3 to 5 ft prevail for the rest of the basin. For the forecast, the fresh to strong winds in the Gulf of Honduras will pulse this evening. By tonight and into Mon morning, moderate to locally fresh trades will prevail across the basin through Thu. ...ATLANTIC OCEAN... A surface trough E of the Windward Islands near 15N58W is coupling with divergent flow aloft to produce numerous moderate to isolated strong convection from 13N to 16N between 55W and the Windward Islands. An upper-level low N of the Dominican Republic near 21N69W is triggering scattered showers and thunderstorms N of Puerto Rico and Leeward Islands from 19N to 26N between 59W and 71W. A stationary front extends westward from 30N70W to just off the N Florida coast. Scattered showers and isolated thunderstorms are noted N of 28N between 72W and the N Florida coast. Refer to the Tropical Waves and Monsoon Trough/ITCZ sections above for additional convection across the Atlantic Basin. An elongated 1030 mb high near 36N45W continue to dominate the NW central Atlantic with light to gentle winds and seas at 3 to 5 ft N of 24N between 31W and the Georgia-Florida coast. Gentle to moderate with locally fresh NW to SW winds and seas of 6 to 8 ft are present N of 27N between 18W and 31W. Gentle to moderate trades and seas at 4 to 6 ft are evident between 12N and 24N between 26W and the Lesser Antilles. Light to gentle winds and seas of 4 to 5 ft prevail across the remainder of the Atlantic Basin. For the forecast west of 60W, a frontal boundary will linger across the area through Mon which will bring showers and thunderstorms across the area. Otherwise, quiescent conditions will prevail through Wednesday. Meanwhile, an area of low pressure is expected to form north of the southeastern Bahamas in a few days resulting from the northern end of a tropical wave interacting with an upper-level trough. Gradual development of this system is possible, and a tropical depression could form by the middle of the week several hundred miles southeast of the Carolinas while it moves northwestward across the western Atlantic. This system has a low chance of formation in the next 48 hours and a medium chance through the next 5 days. $$ Chan