000 AXNT20 KNHC 280545 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 145 AM EDT Mon May 28 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 0500 UTC. ...SPECIAL FEATURES... The center of Subtropical Storm Alberto as of 28/0600 UTC, is located near 28.5N 85.8W, or about 145 nautical miles W of Tampa, FL, or about 105 nautical miles S of Apalachicola, FL. The estimated minimum central pressure is 994 mb. The maximum sustained wind speeds are 55 knots with gusts to 65 knots. Alberto is moving NW, or 315 degrees, 08 knots. Precipitation: widely scattered moderate to isolated strong rainshowers extend from 21N to 26N between 77W and 83W, from Cuba to the Bahamasand the Florida Keys. isolated moderate rainshowers cover the restof the area that extends from 20N northward between 70W in the Atlantic Ocean and 90W in the Gulf of Mexico. This precipitation covers parts of the NW Caribbean Sea, Cuba and the Bahamas, Florida and the Gulf of Mexico and adjacent waters of the Atlantic Ocean. Alberto is expected to move inland, in the Florida Panhandle, by Monday afternoon. Alberto will weaken after the landfall. Public Advisories about Subtropical Storm Alberto are being listed under the WMO header WTNT31 KNHC, and under the AWIPS header MIATCPAT1. The Forecast/Advisories about Subtropical Storm Alberto are being listed under the WMO header WTNT21 KNHC, and under the AWIPS header MIATCMAT1. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 29W from 12N southward, moving westward 10 to 15 knots. The wave shows up well in lower level precipitable water imagery. Precipitation: isolated moderate rainshowers are from 06N southward between 27W and 32W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea near 10N14W, to 06N18W and 04N26W. The ITCZ continues from 03N30W, to 01N37W, to the Equator along 43W. Precipitation: isolated moderate to locally strong rainshowers are to the south of the line 08N13W 07N35W 05N51W. ...DISCUSSION... GULF OF MEXICO... Please read the Special Features section for information about Subtropical Storm Alberto, currently in the northeastern Gulf of Mexico. A NW-to-SE oriented upper level trough passes through Louisiana, beyond the Yucatan Channel, into the NW corner of the Caribbean Sea, and into Central America. Scatterometer data was showing fresh to strong winds in the east Gulf near Alberto. moderate to fresh winds were in the central Gulf, and gentle to moderate winds were in the western Gulf waters. The wave heights were reaching 17 feet near Alberto's center, from 6 feet and higher elsewhere from 25N northward from 90W eastward, and 2-3 ft for the rest of the Gulf waters. Expect for winds and seas to decrease following landfall on Monday. Subtropical Storm Alberto near 28.5N 85.8W 991 mb at 11 PM EDT moving NW at 8 kt. Maximum sustained winds 55 kt gusts 65 kt. Alberto will move to 29.6N 86.2W on Monday morning, then will be inland near 31.2N 86.6W on Monday evening. The winds and the seas will start to decrease after the storm moves inland, with ridging building in from the Atlantic Ocean. A surface trough will impact the southern waters from Wednesday through Friday. CARIBBEAN SEA... A NW-to-SE oriented upper level trough passes through Louisiana, beyond the Yucatan Channel, into the NW corner of the Caribbean Sea, and into Central America. Precipitation: scattered to numerous strong rainshowers are in eastern Honduras and NE Nicaragua, and in the coastal areas of east central Nicaragua. isolated moderate to locally strong rainshowers are elsewhere from Jamaica westward. Scatterometer data has been showing moderate to fresh easterly winds across most of the basin except west of 80W, where gentle to moderate southerly winds were prevailing. Wave heights range from 4 to 6 feet in the far east and west Caribbean Sea, to 5 to 7 feet sea heights will continue between 69W and 74W. High pressure in the central Atlantic Ocean will maintain fresh to strong trade winds in the central Caribbean Sea through the week. The strongest winds are expected in the S central Caribbean Sea. A strong trough will move from the NW Caribbean Sea to the Yucatan Peninsula from Wednesday through early Friday, with associated increasing winds and seas. ATLANTIC OCEAN... The surface pressure gradient between Subtropical Storm Alberto and the Atlantic surface ridge may support increasing wind speeds to near gale-force in the Florida coastal and offshore waters through tonight. An upper level trough extends from a 25N52W cyclonic circulation center, to 18N58W, toward Barbados. Rainshowers are possible from 15N to 30N between 45W and 60W. A surface ridge passes through 32N30W, to 30N48W, to a 1025 mb high pressure center that is near 33N57W, continuing beyond 35N77W and the coast of North Carolina. A tight surface pressure gradient will persist through Monday, as Subtropical Storm Alberto moves through the eastern Gulf of Mexico, while central Atlantic ridging lingers. Winds will be near gale W of 79W and strong between 77W and 79W through tonight. Conditions will improve on Tuesday, as the pressure gradient weakens. It is possible that a cold front or a frontal trough may drop into the NE waters from Wednesday night through Friday night. For additional information please visit http://www.hurricanes.gov/marine $$ MT