473 AXNT20 KNHC 090456 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1256 AM EDT Thu Aug 9 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... ...Tropical Storm Debby... Debby is located near 42.8N/46.5W as of 09/0300 UTC. Estimated minimum pressure is 1000 mb, moving northeast at 11 kt. Maximum sustained winds are 45 kt with gusts to 55 kt. Debby is expected to continue moving northeast while weakening. Debby is forecast to dissipate Friday. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...Caribbean Gale Warning... Gale force winds are over the area north of Colombia from 11N- 13N between 70W-76W until 09/1200 UTC. Please see the Atlantic High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for further details. ...TROPICAL WAVES... A tropical wave axis off W Africa extends from 20N22W to 06N22W, moving W at 15 kt. The wave is associated with a 700 mb trough, and an embedded 700 mb low centered near 13N20W. SSMI TPW shows a moist area S of 14N, and dry air N of 14N. Widely scattered moderate convection is from 08N-13N between 17W-23W. A tropical wave axis in the eastern Atlantic extends from 12N37W to 06N37W, moving W at 15-20 kt. This is a low amplitude and low latitude wave with Saharan dry air N of the wave. SSMI TPW shows a moist area along the wave axis. Scattered showers are noted from 09N-11N between 35W-39W. A tropical wave axis in the central Atlantic extends from 18N52W to 06N52W, moving W at 20 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 wave is affected by Saharan dry air intrusion W of the wave axis and N of 12N. Scattered moderate convection is from 09N-12N between 52W-56W. A tropical wave axis in the W Caribbean extends from 18N89W to 05N89W, moving W at 20 kt. The wave is in a moist environment as indicated by SSMI TPW imagery, especially the southern portion of the wave that is over the E Pacific. The northern portion of the wave over the Gulf of Honduras is under an upper level diffluent environment. Scattered moderate to isolated strong convection is noted within 180 nm of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic near 18N16W and extends southwestward to 10N28W to 08N40W. The ITCZ extends from 08N40W to 07N52W. 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 into the basin. A surface trough extends over the Bay of Campeche from 21N90W to 17N93W with scattered moderate convection within 120 nm of the trough. An upper-level low is centered over the SE Gulf near 27N84W. Another small upper level low is centered near Tamico Mexico at 23N98W. A trough will develop over the Yucatan Peninsula from the early evenings to overnight hours during the next several days, accompanied by a surge of fresh to occasionally strong winds. Otherwise, high pressure ridging will prevail across the area through into early next week, supporting moderate to fresh SE flow over the west central Gulf and off Texas early next week. CARIBBEAN SEA... A tropical wave is exiting the basin. Refer to the section above for details. Gale force winds are along the coast of N Colombia. Please read the Special Features section above for details. The monsoon trough in the SW Caribbean supports scattered moderate convection south of 10N and west of 80W. This pattern will continue through the week. The next tropical wave is forecast to reach the waters east of the Lesser Antilles by early Friday, and move across these islands this weekend. ATLANTIC OCEAN... Tropical storm Debby is over the north-central Atlantic. Refer to the section above for details. Three tropical waves are moving across the basin. See the section above for details. A 1021 mb high is centered over the west Atlantic near 26N74W. A small surface trough is over the W Atlantic from 29N64W to 26N65W. Scattered showers are within 90 nm of the trough. The remainder of the basin is under the influence of a surface ridge, anchored by a 1030 mb high centered near 41N24W. Little change is expected through the next 24-48 hours. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa