000 AXNT20 KNHC 312337 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT Fri Mar 31 2017 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 08N13W to 07N15W. The Intertropical Convergence Zone axis extends from 02N14W to the Equator near 20W then continues through 02S30W to the coast of South America near 03S42W. Scattered moderate isolated strong convection was noted from the Equator to 04S between 30W-43W. Isolated moderate convection is located from 01N-03N between 25W-28W. ...DISCUSSION... GULF OF MEXICO... Broad WSW mid to upper level flow dominates the Gulf of Mexico in the wake of a sheared mid to upper level trough located over the NE Gulf. Strong deep layered subsidence was noted over the northern half of the Gulf while mainly upper level moisture was streaming NE over the southern half of the Gulf. The sheared trough was providing limited support for a weakening/dissipating cold front extending from the Tampa Bay area to 25N87.5W which became a dissipating stationary front to 22.5N94W. A pre-frontal squall line extended from just SW of Fort Myers, Florida to 25N86W. Scattered thunderstorms were noted within 45-60 NM of the squall line. A weak 1012 MB high pressure was noted in the wake of the front near 29N87W. The cold front is expected to dissipate overnight tonight or early Saturday as E to SE return flow increases over the western half of the Gulf by Saturday night. CARIBBEAN SEA... A large upper level anticyclone centered over northern Venezuela dominates the flow over the Caribbean with strong mid to upper level subsidence over most of the basin except for the extreme northwest portion. At the surface conditions remain relatively tranquil across the basin with patches of broken to overcast low clouds with embedded showers over the northern Leeward Islands and within 60 NM either side of a line from 16N66W to 15N73W. light to moderate trade winds of 10-15 KT were noted over the basin. Little change in the overall conditions is expected over the weekend. ...HISPANIOLA... Strong subsidence is noted on water vapor imagery over the island. The latest visible satellite imagery showed locally broken to overcast low clouds with possible embedded showers. The 1200 UTC rawinsonde from Santo Domingo showed limited moisture below 770 MB with strong subsidence above that level. Little change in overall conditions expected through the weekend. ATLANTIC OCEAN... A large complex middle to upper level low is centered over the north-central Atlantic near 43N47W that supports a cold front entering the discussion area near 32N43W. The front extends SW to 26N53W to 24N63W with minimal shower activity either side of the front. A pre-frontal surface trough extends from 32N40W to 23N47W. Widely scattered showers are located within 60 nm either side of the trough. The remainder of the SW North Atlantic is under the influence of a surface ridge anchored by a 1021 mb high centered near 29N65W. A fairly flat middle to upper level trough is moving rapidly off the east coast of the United States. A subtropical jet extends from just N of Trinidad to 16N50W to beyond 20N40W. In the eastern Atlantic...a surface ridge anchored by a 1027 mb high near 36N17W is providing mostly fair conditions and clear skies E of a ridge axis extending from the high SW to 20N35W. For additional information please visit http://www.hurricanes.gov/marine $$ Cobb