000 AXNT20 KNHC 191200 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 800 AM EDT Sat May 19 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. ...TROPICAL WAVES... A central Atlantic tropical wave has an axis that extends from 12N50W to 00N51W, moving W at 10 to 15 kt. This wave appears as a poleward surge in low-level moisture and troughing at 700 mb. Scattered showers are within 300 nm of either side of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea near 10N14W to 04N19W. The ITCZ continues from 04N19W to 00N49W. Besides the convection associated with the tropical wave, scattered moderate and isolated strong convection are from 00N to 05N between 05W and 19W. Isolated moderate convection is within 240 nm of the ITCZ axis between 20W and 40W. ...DISCUSSION GULF OF MEXICO... An upper-level trough with its axis along 87W is interacting with a deep plume of tropical moisture to the east of the trough axis to produce scattered showers and thunderstorms across the eastern Gulf affecting the Florida peninsula, Florida Straits, and the majority of Cuba. A surface trough has developed within this convection extending from 26N79W to 24N80W. This activity is expected to continue through the weekend. A weak ridge axis extends across the basin along 28N producing mainly gentle to moderate winds. The only exception is fresh SE winds near the SE Texas coast. The surface trough is expected move into the eastern Gulf by Sunday. The upper-level trough over the eastern Gulf will remain for several days, and will continue to be the focus for shower and thunderstorm activity mainly over the far eastern Gulf, where deeper moisture and better lift will prevail. CARIBBEAN SEA... An upper-level trough extends over the Yucatan Channel and the northwest Caribbean. Upper-level diffluence on the eastern side of this trough is supporting numerous showers and scattered moderate convection N of 13N between 74W and 84W. The interaction of the upper trough with the nearby E Pacific monsoon trough over Panama is supporting clusters of moderate to strong convection S of 13N between 76W and 83W. Broad high pressure over the subtropical Atlantic continues to support moderate to fresh tradewinds over the NW and E Caribbean, and fresh to strong winds over the central Caribbean. Light winds are occurring over the extreme SW Caribbean near the eastern Pacific monsoon trough. Wave heights of 8 to 10 ft continue to occur over the S 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. The surface ridging pattern over the Atlantic will persist, keeping a similar wind profile in place across the basin into early next week. ATLANTIC OCEAN... A diffluent flow aloft to the east of an upper-level trough currently over the eastern Gulf of Mexico is supporting scattered moderate convection across Florida, the Bahamas, and Atlantic waters mainly west of 74W. Radar and surface observations indicate that a weak NE-SW oriented surface trough is developing over the waters SE of southern Florida. To the east, a 1029 mb high is centered over the central Atlantic near 33N59W. A 1029 mb high is also over the central Atlantic near 33N40W. These centers anchor a very broad ridge that spans the Atlantic waters east of Florida to the northwest African coast. A recent scatterometer pass indicates fresh to strong SE winds over a portion of the NW Bahamas possibly associated with the tightening pressure gradient between the aforementioned surface trough and the high pressure ridge. The pressure gradient between the central Atlantic high and lower pressures in the Caribbean is producing fresh to locally strong easterly winds along the northern coast of Hispaniola and eastern Cuba. Moderate to fresh tradewinds are occurring elsewhere across the central and western Atlantic south of 27N. Gentle to moderate winds cover the central Atlantic N of 27N. Moderate to occasionally fresh NE winds are occurring over the eastern Atlantic. The surface trough SE of S Florida will slowly drift NE across S Florida and into the E Gulf this weekend, increasing the chances for heavy rainfall over central and S Florida. Otherwise, the overall pattern will change little over the weekend, with strong winds expected to continue along the northern coast of Hispaniola, and at times eastern Cuba. For additional information please visit http://www.hurricanes.gov/marine $$ Latto/ERA