000 AXNT20 KNHC 231047 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 647 AM EDT Wed Aug 23 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 0600 UTC surface analysis and satellite imagery through 1015 UTC. ...SPECIAL FEATURES... As of 23/0900 UTC, a tropical wave extends from 26.5N92W to 17N91W moving NW at 10 kt. The remnant circulation of Harvey continues to be analyzed as a 1009 mb low pressure along the wave axis over the Bay of Campeche near 21N92W. Scattered moderate to isolated strong convection is from 20N-24N between 89W-93W. Environmental conditions are conducive for development, and a tropical depression or tropical storm is very likely to form today or tonight while the low moves northwestward across the western Gulf of Mexico, possibly reaching the northwestern Gulf coast late Friday. Regardless of development, this system is likely to slow down once it reaches the coast, increasing the threat of a prolonged period of heavy rainfall and flooding across portions of Texas, southwestern Louisiana, and northeastern Mexico into early next week. This system could also produce storm surge and tropical storm or hurricane force winds along portions of the Texas coast later this week, and Tropical Storm or Hurricane Watches could be required later today for portions of the coast of northeastern Mexico, Texas, and southwestern Louisiana. Interests in these areas should monitor the progress of this system, and refer to products issued by your local National Weather Service office for more information. An Air Force Reserve reconnaissance aircraft is schedule to investigate the low this morning. A gale warning has been issued for the SW and west- central Gulf. See latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC and the Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends from 23N33W to a 1011 mb low within the monsoon trough located near 18N35W to 10N36W, moving W at 15 kt. Satellite imagery indicates a large area of cloudiness in association with this wave, but convection is limited. This wave remains in a very moist area based on TPW imagery and has a well pronounced 700 mb trough. A tropical wave is moving across the central Caribbean and extends from 19N75W to N Colombia near 07N75W moving W at 20 kt. An area of showers is noted near the northern end of the wave axis. The wave is also producing scattered moderate to strong convection over northern Colombia. The wave coincides with a 700 mb trough, and is well depicted in the moisture product. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 14N17W to 17N30W to 18N35W to 09N47W. The Intertropical Convergence Zone axis continues from 09N47W to 08N59W. Besides the convection mentioned in the tropical wave section, scattered moderate to strong convection is along the coast of W Africa from 08N-14N between 16W-23W. Scattered moderate convection is from 09N-14N between 27W-32W, and from 08N- 11N between 35W-43W. ...DISCUSSION... GULF OF MEXICO... Attention remains focused on the remnant circulation of Harvey currently located over the Bay of Campeche. Please, see Special Features section for details. A gale warning has been issued. As of 23/0900 UTC, a surface trough extends from the Florida NE coast near 30N80W to S Florida to a 1013 mb low over the SE Gulf of Mexico near 25N82W. Scattered showers are over the SE Gulf from 23N-26N between 80W-84W. In the upper levels, an upper level low is centered over the NW Gulf near 28N93W enhancing showers. Expect over the next 06 hours for the upper level low to dissipate. Also expect convection over S Florida within the next 48 hours due to the trough. CARIBBEAN SEA... A tropical wave is moving across the central Caribbean Sea. Please, see Tropical Waves section for details. The most recent scatterometer data provide observations of fresh to locally strong SE winds across the NW Caribbean mainly N of 20N W of 83W. Similar wind speeds are noted over the central Caribbean. Strong trade winds are forecast to pulse off the coasts of northeast Colombia and northwest Venezuela in the wake of the tropical wave currently located along 75W. A surface trough over the Atlantic extends to near Barbados in the Windward Islands producing isolated showers. Moisture associated with this trough will affect mainly the Leeward Islands today, reaching the UK/US Virgin Islands tonight. This will increase the chance for showers with isolated tstms across the islands. ...HISPANIOLA... Mostly fair weather is presently over the island. Daytime heating, local sea breezes and mountain upslope lifting will continue to combine with available moisture to produce scattered showers and thunderstorms mainly during the afternnon and evening hours today. ATLANTIC OCEAN... A tropical wave is over the tropical Atlantic. Please see above. Isolated moderate convection is over the northern and central Bahamas. Any development of this system during the next few days should be slow to occur while it drifts over Florida and the adjacent waters. Farther east, a surface trough extends from 31N63W to 26N67W. Scattered showers are within 90 nm of the trough. Another surface trough extends from 25N57W to 20N56W to Barbados near 13N59W. Scattered moderate convection is from 24N- 28N between 54W-56W. A 1021 mb high is centered over the central Atlantic near 33N48W. An upper-level low is also centered near 28N59W. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa