000 AXNT20 KNHC 160531 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 131 AM EDT Sun Jul 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...TROPICAL WAVES... A central Atlantic tropical wave has an axis extending from 04N47W to 15N45W, moving westward around 10 knots. The wave has dry Saharan air to the NE and NW, but is embedded in an area of deep layer moisture. Scattered moderate and isolated strong convection is present from 05N to 10N between 42W and 52W. A central Caribbean tropical wave has an axis extending from northern Colombia at 10N73W to Haiti at 19N72W, moving westward around 20 kt. Scattered moderate and isolated strong convection associated with this wave is over Haiti from 18N to 19N between 72W and 73W and over northern Colombia and the adjacent coastal waters from 08N to 12N between 72W and 76W. The latest rawinsonde sounding from San Juan suggests some of this convection may contain gusty winds. The wave is forecast to move across the rest of the central Caribbean through this afternoon, then across the western Caribbean by Monday evening. A western Caribbean tropical wave has an axis extending from northern Costa Rica at 09N83W to the Island of Pines in Cuba near 22N83W, moving westward at around 20 knots. TPW satellite imagery shows this wave is embedded in a modest area of moisture. There is no significant convection associated with this wave. This wave will cross the remainder of the western Caribbean and enter the Yucatan Peninsula and central America by this evening. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from Senegal is west Africa near 12N16W to 09N30W to 09N46W, then finally to the coast of French Guiana in South America near 06N54W. Aside from the convection related to the tropical wave near 46W, scattered moderate and isolated strong convection is present from 07N to 12N between 14W and 32W and from 04N to 11N between 32W and 42W. ...DISCUSSION... GULF OF MEXICO... A surface trough crosses the central Gulf of Mexico from the northern Yucatan Peninsula to near the Mouth of the Mississippi River. Otherwise, a weak high pressure ridge along the northern Gulf Coast is maintaining a light to gentle wind regime over the Gulf. Upper-level winds converging between high pressure along the northern Gulf Coast and a low pressure trough over the southern Gulf is inhibiting convection, except for the convection associated with diurnal troughing over the Yucatan, which is expected to move over the Bay of Campeche later this morning. This weather pattern is expected to continue during the next 24 hours. CARIBBEAN SEA... A couple of tropical waves are moving through the Caribbean Sea. See the tropical waves section above for details. Beside the tropical wave over the central Caribbean, upper-level winds converging over the basin between high pressure over northern South America and a low pressure trough over Hispaniola and Cuba are inhibiting convection. A relatively light pressure gradient over the area is generating light to moderate trades, except for fresh to locally strong trades along the coast of Colombia and in the vicinity of the Gulf of Venezuela. Little change is expected in these conditions through Monday. ...HISPANIOLA... Generally fair weather prevails across the island at this time. A passing tropical wave is producing some convection over Haiti but shower coverage over western Hispaniola should decrease today as the tropical wave over the central Caribbean continues heading west. ATLANTIC OCEAN... A tropical wave is crossing the central Atlantic. See the tropical waves section above for details. A surface trough is analyzed over the Bahamas from 23N78W to 26N77W. Scattered moderate convection is observed close to Andros Island from 22N to 25N between 76W and 80W. This system is expected to continue heading west toward the Straits of Florida today and into the eastern Gulf of Mexico tonight. Other troughs are analyzed from 25N43W to 30N43W and from 26N65W to 31N63W. Neither one of these troughs has any significant convection associated with it. The remainder of the basin remains dominated by a broad surface ridge, anchored by a 1030 mb high centered just SW of the Azores near 38N30W. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy