000 AXNT20 KNHC 261718 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 118 PM EDT Sat May 26 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... Subtropical Storm Alberto centered near 21.6N 84.9W at 26/1500 UTC moving north at 9 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Alberto is interacting with an upper trough, supporting widespread showers and thunderstorms over the northwest Caribbean, western and central Cuba and the southeast Gulf of Mexico through South Florida. The stronger winds on the northeast side of the center of Alberto are commencing in the southeast Gulf north of western Cuba, allowing seas to build. The forecast calls for gradual development as Alberto moves northward across the central Gulf of Mexico late Mon, making landfall along the north central Gulf coast by early Tue. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 21W/22W south of 15N. The wave shows up well in lower level precipitable water imagery. Scattered moderate convection is noted near this tropical wave and along the monsoon trough from 02N to 06N between 15W and 30W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea near 10N14W to 03N25W. The ITCZ continues from 03N25W to 01S45W. Scattered convection is observed from 02N to 06N between 15W and 30W. ...DISCUSSION... GULF OF MEXICO... Please read the SPECIAL FEATURES section, for information about Subtropical Storm Alberto, in the NW corner of the Caribbean Sea. An sharp negatively tilted upper level trough extends from the lower Mississippi Valley to over the Yucatan Channel. Scattered convection remains active over the eastern Gulf, on the side of this trough, with deep layer dry air west of the trough axis. Seas are likely 6 to 9 ft over the southeast Gulf and building ahead of Alberto's approach. Moderate to fresh SE winds are noted over the northeast Gulf, with 3 to 5 ft seas. Light winds with 1 to 3 ft seas are noted over the western Gulf. Fresh southerly flow will persist over the eastern Gulf through mid week in the wake of Alberto. CARIBBEAN SEA... An upper level trough extends from north central Gulf of Mexico, across the Yucatan Peninsula of Mexico, into the NW corner of the Caribbean Sea. Scattered to numerous strong rainshowers are from 16N to 18N between 16W and 18W. Please read the SPECIAL FEATURES section, for information about Subtropical Storm Alberto, in the NW corner of the Caribbean Sea. Alberto is moving through the Yucatan Channel into the south central Gulf. Winds and seas will decreasing in the far northwest Caribbean Sea in the wake of Alberto. High pressure in the central Atlantic will maintain fresh to strong trade winds in the central Caribbean Sea through mid week, with strongest winds along the coast of Colombia and in the Gulf of Venezuela. ATLANTIC OCEAN... Please read the SPECIAL FEATURES section, for information about Subtropical Storm Alberto, in the NW corner of the Caribbean Sea. Moderate to fresh trade winds are expected S of 25N through Monday, pulsing to fresh to strong offshore of northern Hispaniola during the afternoon through evening hours each day. The pressure gradient will tighten between Alberto in the eastern Gulf and high pressure east of the area, resulting in fresh to strong SE to S winds W of 77W tonight through Sunday night. Those conditions should improve slightly by Tue as the pres gradient slackens after Alberto moves inland over the northern Gulf coast. Farther east, persistent high pressure centered near the Azores will maintain moderate to fresh trade winds over the eastern and central tropical Atlantic, with fresh northerly winds off the North African coast north of 15N, with 5 to 7 ft seas across the region. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen