000 AXNT20 KNHC 200501 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 101 AM 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 0000 UTC surface analysis and satellite imagery through 0400 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 and 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 numerous moderate and isolated strong convection along this corridor. This activity is expected to continue through early this upcoming week, with heavy rainfall and flooding possible over the land areas affected. ...TROPICAL WAVES... A central Atlantic tropical wave has an axis that extends from 13N52W to 03N54W, moving W at 5 to 10 kt. This wave has slowed down its forward motion over the past 24 hours and is expected to become diffuse east of the Caribbean over the next couple of days. Numerous showers and isolated moderate convection are within 300 nm of either side of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea- Bissau near 12N16W to 03N22W. The ITCZ continues from 03N22W to 01N35W to the Brazil coast near 00N49W. Besides the convection associated with the tropical wave, isolated moderate convection is from 01N to 05N between 12W and 51W. ...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 for more details. A surface trough is embedded within this convection, extending from 26N80W to 23N82W, as indicated by an overnight scatterometer pass. 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 into 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. Upper-level diffluence on the eastern side of this trough is supporting scattered to numerous moderate convection across the Caribbean waters between 76W and 83W. 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 10 ft persist over the central Caribbean as confirmed by a recent satellite altimeter pass and current buoy data. Over the next couple of days, the upper-level trough will remain in place enhancing shower and thunderstorm activity over the western Caribbean. A surface trough is expected to develop later today underneath this convection and drift westward. The surface ridging pattern over the Atlantic will persist, keeping a similar wind profile in place across the basin into the middle of this upcoming 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 east-central Florida is supporting scattered to numerous moderate convection across Florida, the Bahamas, and Atlantic waters mainly west of 76W. High pressure centered over the N Central Atlantic spans the Atlantic waters east of Florida to the northwest African coast. Surface observations and latest scatterometer data indicate prevailing fresh to locally strong southeast winds over a portion of the Bahamas as well as within a few hundred miles N of Hispaniola. A recent altimeter pass indicates wave heights of 8 to 9 ft over these waters 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 north to northeast winds are occurring over the eastern Atlantic. The overall pattern will change little through Monday. 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