000 AXNT20 KNHC 130947 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 547 AM EDT Thu Jul 13 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 0945 UTC. ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 16N27W to 05N27W, moving W at 20 kt within the last 24 hours. The wave is in a region of favorable wind shear, however extensive intrusion of Saharan dry air and dust into the wave environment is hindering deep convection. Shallow moisture and middle to upper level diffluence support scattered to isolated showers from 05N to 10N between 22W and 30W. A tropical wave is in the central Atlc with axis extending from 14N49W to 04N50W, moving W at 20 kt within the last 24 hours. The wave is in a region of neutral to unfavorable wind shear, and its environment is being affected by extensive intrusion of Saharan dry air and dust, which limit convection to scattered showers from 04N to 12N between 43W and 55W. A tropical wave is in the E Caribbean with axis extending from 22N64W to 10N65W, moving W at 15 kt within the last 24 hours. The wave is in a region of favorable to neutral wind shear. Abundant moisture and middle to upper level divergent flow support scattered to numerous heavy showers and tstms in the NE Caribbean and adjacent SW N Atlc waters, including Puerto Rico. A tropical wave is moving across northern Central America and EPAC adjacent waters. Its axis extends from 19N87W to 09N89W, moving W at 20 kt within the last 24 hours. The wave is in a region of mainly unfavorable wind shear, and CIRA LPW imagery show large patches of dry air in its environment, which limit the convection to scattered showers S of 20N W of 83W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of W Africa near 14N17W to 09N23W. The ITCZ begins near 09N30W and continues to 07N44W to 06N54W. Aside from the convection associated with the tropical waves, scattered heavy showers are from 02N to 10N between 33W and 44W and from 09N to 14N E of 20W. ...DISCUSSION... ...THE GULF OF MEXICO... A weak surface ridge continues to dominate the Gulf waters producing mainly gentle to moderate E-SE winds. This ridge and wind pattern will persist through later today. A surface trough is moving across the central and southern Florida Peninsula under a divergent wind patter aloft. This is supporting scattered to isolated showers and tstms mainly for SE Florida and the Florida Straits. Looking ahead, a surface trough, associated with the remnants of T.D Four, currently located over the northern Bahamas and the Great Bahama Bank, will move across south Florida later today, and across the E Gulf tonight into Friday, reaching the central Gulf later on Friday. This trough is expected to increase the likelihood of showers with embedded thunderstorms. ...THE CARIBBEAN SEA... The main features in the basin are two tropical waves, one soon moving into the Yucatan Peninsula and another just E of Puerto Rico. See the waves section above for further details. The latest scatterometer pass continue to provide observations of fresh to strong winds over the south-central Caribbean S of 13N between 70W and 75W, including the Gulf of Venezuela. This area of strong trade winds is forecast to continue during the next two days with the strongest winds pulsing at night. The EPAC monsoon trough moves across Costa Rica and Panama to NW Colombia, which underneath upper level divergent flow supports scattered heavy showers and isolated tstms S of 16N W of 78W. Looking ahead, the wave over the E Caribbean will move across Hispaniola Friday with showers. Another tropical wave will enter the E Caribbean Saturday. ...HISPANIOLA... Available moisture associated with a tropical wave in the E Caribbean is producing isolated showers across the Island being the strongest shower activity in S Haiti and adjacent waters. This activity is forecast to continue today and Friday as the tropical wave continues to move west. Then showers are forecast to resume again Saturday night. ...THE ATLANTIC OCEAN... The remnants of T.D. Four continue situated in the SW N Atlc waters across the northern Bahamas and the Great Bahama Bank where it generates scattered to isolated heavy showers and tstms. Farther W a surface trough moves across central and southern Florida under a divergent environment aloft that support scattered to isolated showers mainly over SE Florida and adjacent waters. Model guidance continue to suggest that the trough associated with the remnants of T.D. Four will move across south Florida today with showers. Otherwise, the Bermuda-Azores high extends a ridge across the remainder of the forecast region. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos