000 AXNT20 KNHC 161805 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 PM EDT Tue May 16 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...TROPICAL WAVES... A tropical wave is over the central tropical Atlantic with axis extending from 07N30W to 01N30W, moving westward at about 15 kt. The wave has a subtle signal in satellite imagery, but still appears in model diagnostics. Saharan dry air and dust in the wave environment limit convection to isolated showers within 90 nm either side of its axis. A tropical wave is over the western tropical Atlantic with axis extending from 09N51W to 01N50W, moving westward at around 15 kt. The wave continue to be difficult to locate in satellite imagery, but still appears in model diagnostics. Unfavorable wind shear, dry air and dust in the wave environment inhibit convection at the time. A tropical wave extends from the south-central Caribbean near 12N68W to inland Venezuela and eastern Colombia. Unfavorable wind shear across this region of the Caribbean limit convection to isolated showers S of 12N between 64W and 70W. ...ITCZ/MONSOON TROUGH... The monsoon trough crosses the western African coast near 08N13W to 06N21W. The ITCZ begins near 06N21W and extends to 03N29W, then resumes west of a tropical wave near 03N35W to 04N50W. Aside from the convection related to the tropical waves, scattered showers are within 120 nm of the ITCZ between 20W and 30W. ...DISCUSSION... GULF OF MEXICO... Very stable conditions are across the entire basin being supported by middle to upper level ridging and deep layer dry air. Broad surface high pressure over the mid-Atlantic states and the SE CONUS extends a ridge axis SW to the eastern Gulf of Mexico and provide gentle to moderate return flow. This pattern is forecast to continue through Thursday, except that winds will become fresh to strong N of 24N W of 94W as the pressure gradient tightens due to an area of low pressure building in the central and southern plains. CARIBBEAN SEA... A 1011 mb low pressure developed earlier this morning along a surface trough in the western Caribbean that extends from southern Cuba near 22N80W to the low near 20N82W to 15N81W SW to coastal waters of southern Nicaragua near 11N83W. A middle to upper level diffluent environment between a trough in the W Atlc with base near Honduras and a ridge to the east along with abundant moisture support heavy showers and scattered tstms N of 15N between 70W and 77W, including eastern Cuba, the Windward Passage and Haiti. Scattered heavy showers and tstms are also off the coast of Colombia from 10N to 15N between 74W and 77W. Isolated showers are within 120 nm either side of the surface trough S of 16N. Otherwise, a tropical wave moving inland Venezuela and Colombia support isolated showers in the S-SE basin S of 13N. See tropical waves section for further details. The upper level features generating the diffluent flow aloft will be nearly stationary during the next three days, which will lead to the continuation of showers for the north-central Caribbean. Hispaniola, eastern Cuba and Jamaica will receive numerous showers with the potential for flooding and mud slides. HISPANIOLA... A middle to upper level diffluent environment between a trough in the W Atlc with base near Honduras and a ridge to the east along with abundant moisture support heavy showers and scattered tstms in the north-central Caribbean N of 15N between 70W and 77W, including the Windward Passage, Haiti and western Dominican Republic. The upper level features generating the diffluent flow aloft will be nearly stationary during the next three days, which will lead to the continuation of showers for Hispaniola with the potential for generating flooding and mud slides. ATLANTIC OCEAN... A middle to upper level trough along the W Atlc support a dissipating stationary front that extends from 30N63W to 27N80W. Diffluence aloft between the trough and ridging in the central Atlc support scattered showers N of 20N between 50W and 77W. Otherwise, the remainder basin is under the influence of a surface ridge that supports fair weather. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos