000 AXNT20 KNHC 212353 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 753 PM EDT Mon Aug 21 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... A tropical wave extends from 21N84W to 10N85W moving W-NW at 15-20 kt. The remnant circulation of Harvey continues to be analyzed as a 1008 mb low pressure along the wave axis near 17N84.5W with scattered to numerous showers and thunderstorms occuring from 16N-23N between 80W-89W. The convective activity has increased today, but the system still lacks a well-defined center of circulation, and surface pressures are not falling at this time. Some development of this disturbance is still possible before it reaches the coast of Belize or the Yucatan Peninsula early Tuesday. Regardless of development, locally heavy rainfall and gusty winds will continue to affect mainly western Cuba and the Cayman Islands tonight, and will continue to spread westward across Belize, northern Guatemala, and the Yucatan Peninsula during the next couple of days. The system is forecast to move into the Bay of Campeche on Wednesday, where environmental conditions are expected to be conducive for redevelopment into a tropical cyclone. ...TROPICAL WAVES... A tropical wave extends from 23N24W to 10N29W moving W at 15-20 kt. A 1009 mb low pressure precedes the wave centered near 13N33W. Scattered moderate convection is noted within 120 nm SE of a line from 13N23W to 10N31W. This wave in a moist area based on TPW imagery and has a well pronounced 700 mb trough. A tropical wave is over the far eastern Caribbean and extends from near Antigua to eastern Venezuela at 08N63W moving W at 20-25 kt. Isolated showers are near the northern end of the wave axis. The wave is expected to move across the eastern Caribbean Sea and portions of Venezuela through Tuesday helping to induce some convective activity. Subtle troughing is noted on 700 mb streamline analysis, but some moisture is observed on either side of the wave axis based on the TPW animation. This wave will cross the central Caribbean through mid-week. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 10N31W to 08N40W to 07N43W. The Intertropical Convergence Zone axis continues from 07N43W to 08N51W. Scattered moderate convection is within about 90 nm south of trough between 31W-39W. ...DISCUSSION... GULF OF MEXICO... A large and well defined upper-level low centered over the central Gulf near 26N90W continues to generate scattered to numerous showers and thunderstorms, mainly across the NE and central Gulf. A surface trough is analyzed over the SW Gulf and extends from 25N97W to the Bay of Campeche near 19N94W where some shower activity is noted. The upper-low will drift WNW across the western Gulf on Tuesday and will continue to enhance the development of showers and tstms across the Gulf waters through mid-week. Looking ahead, the remnant low of Harvey, currently moving across the western Caribbean is forecast to move into the Bay of Campeche on Wednesday, where environmental conditions are expected to be conducive for redevelopment into a tropical cyclone. CARIBBEAN SEA... The remnant low of Harvey currently located over the NW Caribbean continues to be the primary area of concern across the basin. Please, see Special Features section for more details. A tropical wave is over the far eastern Caribbean. Please, see the Tropical Waves section for details. Patches of low-level moisture embedded in the trade wind flow are noted over parts of the east and central Caribbean. Fresh SE winds are observed per scatterometer data across the central Caribbean, but maninly N of 13N. These winds are the result of the pressure gradient between the Atlantic ridge and the remnant low of Harvey. ...HISPANIOLA... Daytime heating, local sea breezes and mountain upslope lifting will combined with available moisture to produce isolated to scattered showers and thunderstorms mainly during the afternnon and evening hours. The next tropical wave is forecast to pass just south of the island Tuesday night into Wednesday. ATLANTIC OCEAN... A trough of low pressure continues to move westward across the Bahamas and now extends from 28N74W across the central Bahamas to near 22N76W. This system continues to produce disorganized showers and thunderstorms, with fresh to strong winds mainly on its NW side based on scatterometer data. Only slow development of this system is anticipated during the next several days while it moves west-northwestward across the Bahamas and then turns northwestward or northward near Florida and the adjacent waters. Farther east, there is another surface trough that extends 25N52W to 16N55W. This trough is likely the surface reflection of an upper-level low spinning near 26N57W. The remainder of the forecast area is under the influence of the Atlantic ridge. For additional information please visit http://www.hurricanes.gov/marine $$ GR