000 AXNT20 KNHC 040946 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 546 AM EDT Thu May 4 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURE... A strong cold front is across the NW Gulf of Mexico extending from 29N92W to 27N97W with an outflow boundary ahead of it connecting from a 1007 mb low near 30N92W and then continuing along 29N88W to 30N85W. Heavy showers and potential severe tstms are south of these boundaries to 26.5N along with strong to near gale force southeasterly winds. Gale force winds are forecast to develop near 1500 UTC today south of 24N west of 96W as the front extends from the Florida Panhandle SW to near Tampico, Mexico. High pressure building over the central plains and over Mexico behind the front will weaken thereafter allowing the gale winds to subside by tonight. Please refer to the High Seas Forecast product under AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough crosses the western African coast near 07N13W and extends to 04N24W where the ITCZ begins and continues along 01N35W to the coast of Brazil near 0N50W. Scattered moderate convection is from 06S to 08N west of 16W. A strong squall line with heavy showers and tstms is moving off Sierra Leone into the E Atlc waters east of 15W. ...DISCUSSION... GULF OF MEXICO... A middle to upper level trough across the central plains supports a strong cold front across the NW Gulf of Mexico extending from 29N92W to 27N97W with an outflow boundary ahead of it connecting from a 1007 mb low near 30N92W and then continuing along 29N88W to 30N85W. Heavy showers and potential severe tstms are south of these boundaries to 26.5N along with strong to near gale force southeasterly winds. In addition, dense fog is being reported N of 27N W of 90W with visibility less than 3 miles. Gale force winds are forecast to develop in the SW basin later this morning. Please see the special features section for more details. The front will bring showers across the central and NE basin today and over central and southern Florida Friday. The cold front will exit the straits of Florida early Saturday morning. CARIBBEAN SEA... The Caribbean Sea is very quiet this morning. Shallow convection continues over north-northwest Hispaniola being supported by a middle level diffluent environment just over the Island. Scattered to isolated showers are also being reported in the Leeward Islands supported by an upper level trough and shallow moisture being advected from the tropical Atlc. Latest scatterometer data show mainly moderate trades across the region, except for fresh winds off the coast of northern Colombia S of 14N and in the Gulf of Honduras. Water vapor imagery show dry air subsidence elsewhere, thus supporting fair weather. Showers will continue across Hispaniola today and are forecast for the far NW Caribbean starting Friday as a cold front moves across southern Florida. The front is forecast to enter NW Caribbean waters early Saturday morning. ...HISPANIOLA... Shallow convection continues over north-northwest Hispaniola being supported by a middle level diffluent environment just over the Island. These showers will continue through tonight. ATLANTIC OCEAN... With little support aloft, the tail of a stationary front continues to dissipate this morning from 30N73W to 29N77W. Southeast of this front, a surface trough races across the western Bahamas supporting scattered to isolated showers. Broad surface high pressure dominates the remainder SW N Atlc and central Atlc waters and provides stable and fair weather conditions. Otherwise, a broad middle level low north of the area continue to support a cold front from 30N17W to 22N30W to 21N37W with possible isolated showers within 90 nm either side of the boundary. A new strong cold front is forecast to come off NE Florida Friday morning and move over the northern and central Bahamas Saturday as it weakens. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos