000 AXNT20 KNHC 261716 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 116 PM EDT Thu Apr 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 1715 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through Liberia and continues to 04N22W. The ITCZ extends from 04N22W to 03N30W to 01N40W to the Equator at 50W. A cluster of moderate to strong convection is noted over parts of Sierra Leone and Liberia, and the adjacent Atlantic waters from 05N-07N E of 13W. Similar convection is also seen elsewhere from 03N-06N between 10W-15W. Scattered moderate convection is within about 90 nm S of ITCZ axis between 22W-25W, and near the Equator at 32W. ...DISCUSSION... GULF OF MEXICO... As of 1500 UTC, a cold front extends from SE Louisiana to the coast of Tamaulipas, Mexico near 25N97W. An area of showers with embedded tstms is ahead of the front over the SW gulf, including the Bay of Campeche, associated with a short-wave trough moving across that area. The front will reach the SE Gulf Sat where it will stall and dissipate. High pressure will build in the wake of the front and prevail through Mon. Under the influence of this system, a gentle to moderate anticyclonic flow will prevail across the gulf waters, with seas generally under 5 or 6 ft. A nearly stationary front is over the far SE gulf and the Straits of Florida producing scattered showers and tstms. It is forecast to become diffuse late today. A weak 1015 mb high pressure is centered over the SE Gulf near 25N84W. This system will move across South Florida into the Bahamas through tonight keeping dry weather conditions over South Florida. A thermal trough will develop during the evening hours over the Yucatan peninsula before pushing offshore into the SW gulf each night. A surge of moderate to fresh NE-E winds will accompany this trough, with seas building to around 5 ft. CARIBBEAN SEA... As previously mentioned, a nearly stationary front is over the far SE Gulf of Mexico and the Straits of Florida. Scattered showers and tstms are along the frontal boundary. Part of this convective activity is reaching western Cuba and the Yucatan Channel. The front is forecast to become diffuse late today. A surface trough is moving across Puerto Rico generating scattered showers and isolated thunderstorms over parts of the UK/US Virgin Islands and adjacent waters, and across eastern Puerto Rico. Additional showers and thunderstorms are expected to develop across the island during the afternoon hours. Moisture associated with this trough will reach Hispaniola late today. The most recent scatterometer data show moderate SE winds behind the trough axis as well as fresh trades across the ABC Islands and the Gulf of Venezuela. Fresh to locally strong trade winds will prevail over the south-central Caribbean through Sat night. Moderate trades are expected elsewhere through Mon. ATLANTIC OCEAN... As of 1500 UTC, a nearly stationary front extends from 31N71W southwest across the central Bahamas and the Straits of Florida. An area of showers and tstms is over the central Bahamas and regional waters in association with this frontal boundary. This front will dissipate late today. A second cold front will move into the northwest waters Fri night, reach from 31N74W to southern Florida Sat night, then slowly dissipate by Sun morning. A third cold front will push south of 31N Sun, and reach from 30N65W to the northern Bahamas Mon night. Another cold front enters the forecast area near 31N45W and continues SW to 23N50W to 24N58W. Scattered showers and tstms are along the front N of 25N. The front is associated with a weak 1016 mb low pressure that moved into the forecast waters since yesterday. A well defined swirl of low clouds is associated with the low center, forecast to dissipate in about 24 hours. A recent ASCAT pass indicates fresh winds on the NW quadrant of the low center. The remainder of the Atantic Ocean is under the influence of a 1030 mb high pressure located SW of the Azores near 35N30W. The pressure gradient between this high and lower pressure over Africa is resulting in moderate to fresh northerly winds between the coast of Africa and 20W and N of 15N. For additional information please visit http://www.hurricanes.gov/marine $$ GR