000 AXNT20 KNHC 071018 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 618 AM EDT THU JUL 7 2016 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 1015 UTC. ...TROPICAL WAVES... A tropical wave is in the tropical east Atlantic with axis near 31W, moving west at 15 knots within the last 24 hours. The wave is embedded in a moderate moist environment from surface to 850 mb as indicated by CIRA LPW imagery. Weak deep layer wind shear and a diffluent environment aloft allow for the development of scattered showers from 03N-11N between 28W and 39W. A tropical wave is in the west tropical Atlantic with axis near 54W, moving west at 20 knots within the last 24 hours. The wave environment from the surface to 850 mb is mainly dry, also noticed on Meteosat imagery showing Saharan dry air and dust. The exception is the southern region of the wave where ITCZ moist air supports scattered showers from 7N-11N between 50W and 57W. A tropical wave is in the central Caribbean with axis near 78W, moving west at 15 knots within the last 24 hours. A low to moderate moist environment from the surface to 850 mb is associated with the wave. The wave is also embedded in an environment of strong deep layer wind shear that hinder convection activity at the time. ...ITCZ/MONSOON TROUGH... The monsoon trough extends across Africa into the E Tropical Atlantic near 12N16W to 08N27W. The ITCZ extends from 07N32W to 07N45W to the coast of Guyana near 06N57W. Aside from the convection associated with the tropical waves, scattered showers are from 05N-12N between 43W and 50W and from 05N-10N E of 16W. ...DISCUSSION... GULF OF MEXICO... Broad surface ridging across the central Atlantic continues to extend westward over the Florida Peninsula and the entire Gulf of Mexico basin. In the Gulf, the ridge is being anchored by a 1019 mb center of high pressure near 28N84W that provides variable light winds in the NE basin. Moderate return flow dominates elsewhere, except within 90 nm off the western Yucatan Peninsula where a heat trough locally tighten the pres gradient to support E-NE fresh wind. No major changes are expected during the next two days. CARIBBEAN SEA... The main feature in the basin continues to be a weak tropical wave with axis near 78W. Strong deep layer wind shear across the central Caribbean hinders in part the development of convection nearby the wave. Please see the tropical waves section for more details. The presence of the wave in the central basin tightens the gradient of pres and support a broad region of moderate to strong trades S of 18N between 68W and 82W, except along the coast of Colombia where winds increase to near-gale force. Otherwise, scattered showers and tstms are within 60 nm off Panama and Costa Rica. The tropical wave will move into Central America early Saturday while a second tropical enters the eastern Caribbean. ...HISPANIOLA... Mainly dry air and strong deep layer wind shear are across the Island suppressing the development of convection this morning. Stable conditions are expected to prevail through this afternoon. Model guidance indicates the development of showers tonight. ATLANTIC OCEAN... The main features across the basin are the two tropical waves discussed in the section above. Otherwise, a broad surface ridge dominates the remaining Atlantic waters being anchored by a 1025 mb center of high pres SW of the Azores near 32N31W. A tight pres gradient between this ridge and lower pres associated with the monsoon trough support fresh to strong N flow within 270 nm off the Mauritania and Western Sahara coasts. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS