000 AXNT20 KNHC 051758 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 158 PM EDT Sat Aug 5 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... A tropical wave extends from 09N77W to 18N75W moving W at 10-15 kt. The wave continues moving within the southern periphery of a mid- level ridge anchored over the SW North Atlc near 28N72W and remains embedded within an area of slowly organizing 700mb-850mb relative vorticity maxima over the SW Caribbean Sea. Scattered moderate and isolated strong convection is occurring from 10N-17N between 71W-78W. ...TROPICAL WAVES... A 1012 mb low is embedded within the monsoon trough within a broad monsoonal gyre focused near 09N36W. The circulation remains elongated with influence stretching across the waters from 06N-15N between 30W-45W. This area also encompasses a tropical wave analyzed from 13N31W to 20N29W that is expected to sweep westward and inject energy into the gyre and the associated surface low. Global models suggest 850 mb relative vorticity stretches from the low along the monsoon trough axis to the tropical wave. Farther west...another tropical wave analyzed from 09N43W to 14N45W continues to dampen as energy has already been absorbed by the gyre in the past 24 to 36 hours which is mentioned below. While the circulation continues to remain disorganized...widely scattered moderate convection is from 06N-14N between 32W-41W. A tropical wave extends from 13N31W to 20N29W moving W at 10-15 kt. The wave remains to the NE of a monsoonal gyre providing the focus as a special feature which is detailed in the above paragraph. 700 mb troughing is noted between 26W-34W with a maximum in 850 mb relative vorticity in the vicinity of 14N31W. The wave is expected to move N across the monsoonal gyre and inject energy into the broad low pressure area currently analyzed as a 1012 mb low near 09N36W. A tropical wave extends from 09N43W to 14N45W moving W at 5-10 kt. The wave continues to dampen out and is expected to dissipate later this afternoon becoming absorbed by the low pressure area mentioned in the above paragraph. A complex of scattered moderate convection is from 08N-12N between 43W-46W. A tropical wave extends from 08N55W to 17N49W moving W at 5-10 kt. The wave coincides with relatively broad 700 mb troughing between 49W-57W as a 1014 mb low is noted on visible satellite imagery centered along the wave axis near 12N53W. Widely scattered moderate convection remains W of the wave axis from 11N-16N between 50W-56W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 11N15W to 14N28W to 08N39W to 11N48W. The Intertropical Convergence Zone axis extends from 11N48W to 12N53W then from 07N57W to 07N58W. Aside from convection associated with the tropical waves... scattered moderate convection is from 07N-11N between 17W-23W... and from 07N-09N between 27W-30W. ...DISCUSSION... GULF OF MEXICO... A middle to upper level trough is noted on water vapor imagery over the eastern CONUS this afternoon with the base of the trough extending over the north-central Gulf waters. The troughing supports a weak surface trough boundary extending from the Florida panhandle W-SW across the Mississippi River delta region to near the Louisiana and Texas border near 30N94W. Low-level moisture convergence is maximized along the boundary with scattered showers and isolated tstms occurring mainly N of 27N and across inland portions of northern Florida...including the panhandle region...and southern Georgia. The boundary is expected to remain nearly stationary through tonight along the coast...then lift northward and dissipate Sunday. Elsewhere...a surface ridge extends across the central Florida peninsula to the NE coast of Mexico near 23N98W. Mostly clear skies and fair conditions are expected to persist with the ridge remaining in place across the basin through Monday of next week. Thereafter...the northern extent of energy from a tropical wave currently analyzed along 76W will progress W-NW across the Yucatan peninsula Monday night into Tuesday and bring increased cloudiness...strong winds...and convective precipitation to the peninsula and SW Gulf waters. CARIBBEAN SEA... A tropical wave is moving across the western Caribbean along 76W generating a broad area of scattered showers and tstms from 08N- 17N between 71W-78W. The wave is expected to bring increased precipitation to Central America and the Yucatan peninsula late tonight through Tuesday. Elsewhere...low-level moisture convergence of moderate to fresh trades is generating scattered showers and tstms across NE Nicaragua and eastern Honduras. Looking ahead...the arrival of the low pressure area and associated tropical wave between 30W-40W is forecast to impact the Lesser Antilles and surrounding adjacent coastal waters by late Tuesday night into Wednesday bringing increased probabilities of convection and strong winds. ...HISPANIOLA... Lingering isolated showers and tstms are occurring across the island and adjacent coastal waters this afternoon as a tropical wave analyzed to the SW along 76W continues to move west. Conditions are expected to improve through the overnight hours into Sunday as any remaining convection is expected to dissipate. ATLANTIC OCEAN... Across the SW North Atlc...an upper level ridge remains anchored in the vicinity of 27N72W supporting a 1022 mb high centered near 29N70W and a ridge axis extending westward to the southern Florida peninsula and into the southern Gulf of Mexico. Mostly fair skies and tranquil conditions prevail...however with the presence of a middle to upper level trough over the eastern CONUS...scattered showers and isolated tstms are occurring generally NW of a line from Cape Canaveral Florida to 32N75W. Another area of scattered showers and isolated tstms is occurring in the vicinity of a surface trough analyzed from 34N56W to 31N60W. This convection covers the area within 90 nm either side of a line from 26N67W to 32N59W. The ridge is forecast to move northward slightly and keep any significant deep convection generally N of the discussion area. Otherwise...the remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by the aforementioned 1022 mb high and another 1024 mb high centered near 29N47W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN