103 AXNT20 KNHC 061149 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 749 AM EDT Thu Sep 6 2018 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...SPECIAL FEATURES... Hurricane Florence is centered near 24.1N 47.9W at 06/0900 UTC, or 1020 nm ESE of Bermuda, moving NW at 10 kt. Estimated minimum central pressure is 964 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Scattered moderate convection is noted from 23N-27N between 44W-49W. The latest forecast of Florence keeps it in its present motion through today, before it turns to the west- northwest tonight as it weakens. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC for more details. Tropical Depression Gordon is centered near 33.7N 91.3W at 06/0900 UTC, or 100 nm NNW of Jackson Mississippi, moving WNW at 7 kt. Estimated minimum central pressure is 1015 mb. Maximum sustained wind speed is 20 kt with gusts to 25 kt. The threat continues for heavy rain as Gordon is expected to produce total rain accumulations of 2 to 4 inches over portions of western Mississippi, southern and western Arkansas, and from western to northern Missouri into adjacent parts of Illinois with isolated maximum amounts of 6 inches through early Sat This rainfall will cause flash flooding across portions of these areas.Future information on Gordon can be found in Public Advisories issued by the Weather Prediction Center under AWIPS header TCPAT2, WMO header WTNT32 KWNH, and on the web at https://www.wpc.ncep.noaa.gov. For specific local information on Gordon for the affected states, please refer to products issued by your located National Weather Service office. A broad and elongated area of low pressure is centered several hundred miles west-southwest of the Cabo Verde Islands near 13N30W. A tropical wave extends along 30W between 03N20N. The associated shower and thunderstorm activity has changed little in organization since yesterday, and there are no indications yet that the system has a well-defined center of circulation. However, environmental conditions are conducive for development, and a tropical depression is expected to form within the next few days while the system moves slowly westward or west- northwestward across the tropical Atlantic. The chance of this system becoming a tropical cyclone during the next 48 hours is high. Please read the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more information. ...TROPICAL WAVES... A tropical wave is well inland the coast of western Africa. In advance of this tropical wave, large clusters of scattered moderate to strong convection are just offshore the coast of Africa from Sierra Leone to northern Senegal and well inland the coast between these two locations. The tropical wave is forecast to move off the west coast of Africa on Fri. A tropical wave has its axis along 89W and south of 21N to across western Nicaragua, and continues southward to the eastern Pacific near 05N, moving westward at 10 to 15 kt. Scattered moderate convection is within 60 nm either side of the wave over Honduras. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Mauritania near 19N16W, to the 1008 mb low that is associated with the Special Features section tropical wave along 29N. It continues from this system to 08N38W. The ITCZ extends from 08N38W to 07N46W to 07N52W. Outside convection described with the Special Features tropical wave and low along 29W, only scattered moderate convection is seen north of the monsoon trough within 30 nm of a line from 11N33W to 11N36W. Scattered strong convection is over the far eastern Atlantic offshore the coast of Africa within 45 nm either side of a line from 10N16W to 10N21W. ...DISCUSSION... GULF OF MEXICO... Upper-level cyclonic wind flow, with an inverted trough, covers the western one-third of the Gulf of Mexico. Upper level anticyclonic wind flow, with a ridge, covers the rest of the Gulf of Mexico. Scattered moderate isolated strong convection is concentrated over the western gulf to the west of 94W and south of 27N. Isolated showers and thunderstorms are elsewhere across the gulf. A weak surface ridge will build from the Carolinas to the coast of Texas in the wake of Gordon. Expect gentle to moderate easterly winds and modest seas into early next week. The exception will be fresh winds pulsing off the west coast of the Yucatan Peninsula, mainly during the late evening hours, due to a daily trough that sets up in the SW corner of the Gulf of Mexico. CARIBBEAN SEA... Upper level cyclonic wind flow covers the Caribbean Sea to the west of the line that runs from Puerto Rico to La Peninsula de la Guajira of northern Colombia. Isolated moderate to locally strong rainshowers are in the area of upper level cyclonic wind flow. The easternmost part of the eastern Pacific monsoon trough is along 09N/10N from 74W in Colombia beyond western sections of Costa Rica. Scattered showers and thunderstorms are seen from 10N to 12N between the coast of Colombia and 78W. A relatively weak surface ridge in the western Atlantic Ocean will maintain moderate to fresh trade winds in most of the region through late Sun. ATLANTIC OCEAN... Please read the Special Features section above for details about Hurricane Florence. A second area of interest pertains to a broad area of low pressure in the far eastern Atlantic. It has a high chance of tropical cyclone formation during the next 48 hours. An upper-level trough extends from near Bermuda to a westward moving broad upper-level low at 25N74W, and southwest to the Windward Passage. From there it continues to Nicaragua and Costa Rica and to southwestern Caribbean Sea. Upper-level cyclonic flow covers the Atlantic Ocean from the Greater Antilles northward from 60W westward. A surface trough is analyzed from near 31N70W to the central Bahamas. Another surface trough is analyzed from near 31N62W to 27N64W. Satellite imagery shows an area of scattered showers and thunderstorms concentrated from 24N to 30N between 67W and 76W. Scattered showers and thunderstorms are also seen from 22N to 24N between 72W and 77W. A weak pressure pattern will maintain gentle to moderate easterly winds across the area through Sun night. Easterly swell from Hurricane Florence will move into the open waters east of the Bahamas from through Sun. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre/ERA