584 AXNT20 KNHC 080538 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 137 AM EDT Wed Aug 8 2018 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 0515 UTC. ...SPECIAL FEATURES... ...Sub-tropical Storm Debby is located near 40.3N/49.1W as of 08/0300 UTC. Estimated minimum pressure is 1008 mb moving north at 11 kt. Maximum sustained winds are 35 kt with gusts to 45 kt. A turn toward the northeast is expected by Wednesday night. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...Caribbean Gale Warning... A Gale Warning is in effect for the south-central Caribbean from 11N-14N between 70W-76W. The gale is forecast to end on 08/1500 UTC. The gale is forecast to resume on 09/0000 UTC ,and then end again on 09/1500 UTC. Please see the Atlantic High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for further details. ...TROPICAL WAVES... A tropical wave axis in the eastern Atlantic extends from 20N28W to 06N31W, moving W at 15 kt. The northern part of the wave is affected by Saharan dry air intrusion. Scattered moderate convection is from 10N-13N between 27W-30W. A tropical wave axis in the central Atlantic extends from 19N44W to 07N45W, moving W at 15 kt. This wave has a well defined inverted V surface pattern noted on satellite imagery. The wave also has a large 700 mb trough associated with the wave. The northern part of the wave is affected by Saharan dry air intrusion. Scattered showers are within 240 nm of the wave axis S of 16N. A tropical wave in the E Caribbean extends from 13N61W to 05N61W, moving W at 15 kt. This wave is now a low amplitude and a low latitude wave. The wave continues to be affected by intrusion of Saharan dry air and dust. This wave is forecast to dissipate over South America today. Scattered showers are within 90 nm of the wave inland over Venezuela. A tropical wave axis in the W Caribbean extends from 20N80W to 05N81W, moving W at 15 kt. The wave is in a moist environment at the lower levels as indicated by SSMI TPW imagery. It is also under an upper level diffluent environment. Scattered moderate to isolated strong convection is within 240 nm W of the wave axis, and within 120 nm E of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic near 19N16W and extends southwestward to 10N25W then westward to 08N43W. The ITCZ begins W of a tropical wave near 09N46W and continues to 06N57W. Besides the convection mentioned in the tropical wave section, scattered showers are observed within 180 nm S of the ITCZ. ...DISCUSSION... GULF OF MEXICO... An area of high pressure extends from the western Atlantic to the NE Gulf of Mexico waters. A surface trough is over the SE Gulf from 27N83W to 23N85W with scattered showers within 120 nm of the trough. Another surface trough is inland over the Yucatan peninsula. In the upper levels, a small upper level low is centered over the Straits of Florida near 24N81W. Another upper level low is centered over the NW Gulf near 28N94W. A thermal trough will develop over the Yucatan Peninsula from the early evenings to overnight hours for the next several days. A surge of fresh to occasionally strong winds will be associated with this trough. The SE Gulf trough is forecast to move westward over the tonight and Wed while dissipating. Otherwise, high pressure ridging will prevail across the area through the week. CARIBBEAN SEA... Two tropical waves are moving across the basin. Refer to the section above for details. A Gale Warning is also in effect. Please check the Special Features section above for details. The monsoon trough in the SW Caribbean supports scattered moderate convection south of 13N and west of 80W. This pattern will continue through midweek. The next tropical wave is forecast to reach the waters E of the Lesser Antilles late Thu, and move across these islands on Fri. ATLANTIC OCEAN... Sub-tropical storm Debby is over the central Atlantic. Refer to the section above for details. Two tropical waves are moving across the basin. See the section above for details. A 1020 mb high is centered over the W Atlantic near 31N68W. A small surface trough is also located over the W Atlantic from 29N66W to 26N66W. Scattered showers are within 60 nm of the trough. The E Atlantic is under the influence of a broad area of high pressure supporting fair weather. In the upper levels, a large upper level trough is over the central Atlantic N of 26N between 40W-60W. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa