000 AXNT20 KNHC 130606 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 206 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 16N25W to 05N28W, 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 11N between 22W and 30W. A tropical wave is in the central Atlc with axis extending from 13N47W to 04N44W, 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 isolated showers from 07N to 11N between 42W and 48W. A tropical wave is in the E Caribbean with axis extending from 20N64W to 10N64W, moving W at 15 kt within the last 24 hours. The wave is in a region of favorable wind shear. Shallow moisture and middle level divergent flow support scattered to isolated showers and tstms in the NE Caribbean and adjacent waters, including Puerto Rico. A tropical wave is moving across the NW Caribbean and Central America with axis extending from 20N86W to 09N88W, 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 to isolated showers S of 21N W of 83W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of W Africa near 13N17W to 08N24W to 04N39W. The ITCZ begins near 04N39W and continues to 05N54W. Aside from the convection associated with the tropical waves, scattered heavy showers are from 07N to 10N between 33W and 41W and from 09N to 12N 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 heavy showers and tstms for these areas of Florida as well as adjacent SE Gulf waters S of 26N E of 82W, including the Florida Straits. Similar convection continues in the E Bay of Campeche being supported by a tropical wave that moves across the far NW Caribbean waters and northern Central America. Looking ahead, a surface trough, associated with the remnants of T.D Four, currently located over E Cuba, will move across south Florida later today, and across the E Gulf Thursday night 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 moving across the NW Caribbean waters and another over E basin. 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. The EPAC monsoon trough moves across southern Costa Rica and northern Panama to a 1010m mb low over the SW Caribbean near 11N78W. These features are underneath upper level divergent flow aloft, which is supporting scattered heavy showers and tstms S of 16N W of 80W. 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 scattered showers to isolated showers across the Island. This activity is forecast to continue today and Friday as the moves continue 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 E Cuba while it further weakens. Farther W a surface trough moves across central and southern Florida under a divergent environment aloft that support scattered heavy showers and tstms extending offshore. Model guidance continue to suggest that a trough associated with the remnants of T.D. Four will move across the Bahamas reaching south Florida today. 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