000 AXNT20 KNHC 090531 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 130 AM EDT Wed May 9 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 0430 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough meanders westward across tropical western Africa and terminates along the coast of Guinea-Bissau near 12N16W. The ITCZ begins near 06N14W and continues to 01N30W to 00N45W to the coast of northern Brazil near 01S47W. Scattered moderate and isolated strong convection are within 150 nm of either side of the ITCZ axis between 14W and 26W and between 31W and 43W. ...DISCUSSION GULF OF MEXICO... Dry air and subsidence continues to support fair conditions over the northern half of the Gulf basin. A 1018 mb high is centered near 28N94W and is supporting gentle to moderate winds over the majority of the Gulf basin this morning. These winds are producing seas generally between 1 to 3 ft. Remnant moisture associated with a recently dissipated stationary front extending over the Florida Keys and the SE gulf is supporting scattered showers and isolated thunderstorms S of 25N and E of 85W. A weak upper level disturbance over the SW Gulf is likely supporting scattered showers over that portion of the basin. The high pressure will shift east toward the northeast Gulf through Friday, then into the Atlantic on Saturday. This will produce moderate NE to E winds and 3 to 4 ft seas across the eastern Gulf through that period. High daily temperatures over the Yucatan peninsula will set up a weak thermal trough each evening, which will move westward over the eastern Bay of Campeche overnight then dissipate by afternoon each day beginning Wed. CARIBBEAN SEA... A surface trough extends from the Bahamas, across central Cuba near 22N79W to a weak 1014 mb low centered near 19N82W. Another surface trough extends from 18N80W to a 1011 mb low near the coast of Colombia at 10N75W. Scattered showers are occurring within 90 nm of the NW Caribbean low. Scattered showers with embedded clusters of thunderstorms are observed within 90 nm of either side of the central Caribbean trough, with additional shower and thunderstorm activity N of 18N between 75W and 80W, on the eastern side of an upper level trough. The weak pressure pattern over the NW Caribbean supports mainly moderate winds. The pressure gradient between central Atlantic high pressure and lower pressures over S America supports moderate to fresh trades over much of the remainder of the Caribbean basin. Recent altimeter passes and buoy data indicate 3 to 5 ft seas over the W Caribbean, and 5 to 6 ft seas elsewhere. The troughs are expected to drift westward and weaken through mid week, but will remain the focus for showers and a few thunderstorms. Trade wind flow will increase over the south central Caribbean by Fri night as ridging builds north of the region. Little change is expected otherwise over the next few days. ATLANTIC OCEAN... A dissipating stationary front extends from 31N75W to 27N77W, while a pre-frontal trough extends from 29N74W to 22N79W. The combination of these features and an upper trough to the west supports scattered moderate convection with thunderstorms within 300 nm east of the trough. Moderate to locally fresh NE winds are W of the front, while moderate to fresh SE winds cover the western Atlantic E of the front. Farther east, A 1032 mb high centered near 35N48W dominates the central and eastern Atlantic. Latest observations indicate fresh trades covering much of the tropical N Atlantic waters S of 15N, with generally moderate winds N of 15N. The long fetch of fresh trades supports seas of 6 to 8 ft over those waters. The winds to the E of the front will diminish to moderate through today as front dissipates. A ridge will build over the waters north of 25N after the front dissipates, supporting generally moderate to fresh winds south of 22N east of the Bahamas, but with pulses of fresh to strong winds off the north coast of Hispaniola mainly at night. For additional information please visit http://www.hurricanes.gov/marine $$ Latto