000 AXNT20 KNHC 210001 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 801 PM EDT Sun May 20 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... An upper-level trough extends across the eastern Gulf of Mexico and western Caribbean, with diffluent flow aloft prevailing across the Florida Peninsula, the western Atlantic, and Caribbean, to the east of the upper trough's axis. This pattern is drawing deep tropical moisture northward from the SW Caribbean between 76W and 83W and is supporting scattered to numerous moderate convection along this corridor. This activity is expected to continue through at least Tuesday, with heavy rainfall and flooding possible over the land areas affected. ...TROPICAL WAVES... A central Atlantic tropical wave has an axis that extends from 13N30W to 01N30W, moving W at 10 to 15 kt. This wave is embedded in a sharp 700 mb trough. Although deep moisture accompanies the wave, subsidence from aloft is inhibiting convection except over the southern portion. Scattered moderate convection is from 01N to 03N between 26W and 33W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through coastal Africa near 14N17W to 08N26W. The ITCZ extends west of a tropical wave from 02N32W to 01N49W. Besides the convection associated with the wave, isolated moderate convection is from 01N to 06N between 06W and 26W. ...DISCUSSION GULF OF MEXICO... An upper-level trough prevails across the eastern Gulf, with an axis along 85W. Diffluent flow aloft east of the trough is bringing tropical moisture over the far east Gulf and western Atlantic waters affecting the Florida Peninsula and Florida Straits/Keys. Please refer to the Special Features section above for more details. A surface trough is embedded within this convection, extending across central Florida and adjacent waters to near 23N85W. A weak ridge axis extends across the remainder of the basin along 30N producing mainly gentle to moderate winds. The surface trough is expected move NW across the eastern Gulf through Monday. The upper-level trough over the eastern Gulf will remain nearly stationary through the first half of this upcoming week, supporting ongoing convection over the eastern Gulf. CARIBBEAN SEA... An upper-level trough extends over the eastern Gulf of Mexico and western Caribbean. A surface trough is over the western Caribbean with an axis extending from 21N82W to 12N83W. The combination of upper- level diffluence on the eastern side of the upper-level trough and convergence associated with the surface trough is supporting scattered to numerous moderate convection across the Caribbean waters between 78W and 84W. Broad high pressure over the subtropical Atlantic continues to support moderate to fresh tradewinds over most of the basin, except fresh to strong winds over the central Caribbean. Wave heights of 8 to 9 ft persist over the central Caribbean as confirmed by a recent satellite altimeter pass and current buoy data. Over the next day or so, the upper-level trough and surface trough will remain nearly stationary enhancing shower and thunderstorm activity over the western Caribbean. The surface ridging pattern over the Atlantic will persist, keeping a similar wind profile in place across the basin into the middle of this week. ATLANTIC OCEAN... Diffluent flow aloft to the east of an upper-level trough currently over the eastern Gulf of Mexico, combined with a surface trough extending just offshore of northern Florida is supporting scattered to numerous moderate convection across Florida, the Bahamas, and Atlantic waters mainly west of 76W. To the east, high pressure centered over the central Atlantic spans across the basin. Surface observations and latest scatterometer data indicate prevailing fresh to locally strong southeast winds over the Bahamas as well as within a few hundred miles north of Hispaniola. A recent altimeter pass indicates wave heights of 8 to 9 ft over these waters as far as 26N outside of the Bahamas. Moderate to fresh tradewinds are occurring elsewhere across the central and western Atlantic south of 27N. Gentle to moderate winds cover the central Atlantic north of 27N. Moderate to occasionally fresh northeast winds are occurring over the eastern Atlantic. The overall pattern will change little through the next 24 hours. Therefore, the chances for heavy rainfall over the Florida Peninsula, Bahamas, and western Atlantic will continue. For additional information please visit http://www.hurricanes.gov/marine $$ Latto