000 AXNT20 KNHC 012331 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 730 PM EDT Fri Sep 1 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 2245 UTC. ...SPECIAL FEATURES... Hurricane Irma is centered near 18.8N 39.1W at 01/2100 UTC or about 1300 nm E of the Leeward Islands moving W at 11 kt. Estimated minimum central pressure is 964 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Numerous moderate is within 75 nm of center. Scattered moderate is elsewhere from 16N-22N between 35W-43W. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends from 07N25W to 17N26W moving W at 10-15 kt. The wave coincides with 700 mb troughing between 19W-29W and a maximum in 850 mb relative vorticity lagging behind the wave in the vicinity of a 1013 mb low centered along the monsoon trough near 09N22W. Scattered moderate convection is from 06N-14N between 23W-30W. A tropical wave extends from 10N57W to 21N55W moving W at 5-10 kt. The wave coincides with 700 mb troughing between 52W-59W and continues to interact with an upper level low and associated troughing to the N-NE near 24N54W. Isolated moderate convection is from 17N-22N between 55W-61W. A tropical wave extends from 10N86W to 20N86W moving W at 10-15 kt. The wave coincides with subtle 700 mb troughing on the southwestern periphery of a mid-level ridge anchored over the SW North Atlc near 29N73W. Scattered moderate convection is from 10N-17N between 81W-87W...including inland portions of Nicaragua and Honduras. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 12N17W to 07N26W then resumes near 14N42W to 13N53W. Isolated moderate convection is from 06N-13N between 36W-47W. ...DISCUSSION... GULF OF MEXICO... Water vapor imagery indicates a middle to upper level trough extending from over the Ohio River valley and southern Mississippi River valley to a base over the NW Gulf near 26N94W. The troughing supports a cold front extending across western Georgia and SE Alabama...across the western Florida panhandle near 31N87W to 29N90W. A pre-frontal surface trough extends from 30N86W to 26N89W. East of the upper level troughing...upper level divergence is maximized over the eastern Gulf this evening and along with the boundaries mentioned above are generating scattered to numerous showers and scattered tstms N of 23N between 80W-89W...including portions of the Florida peninsula. Upper level divergence is also maximized over the SW Gulf and along with a surface trough from 19N94W to 25N96W...these features are providing focus for scattered showers and tstms S of 25N between 86W-98W...including much of the Yucatan peninsula and southern Mexico. Otherwise... outside of ongoing convection...mostly light to moderate weak anticyclonic flow is noted as a weak ridge axis extends across the Florida Straits through 26N90W to Texas coast near Galveston Bay. CARIBBEAN SEA... A tropical wave is moving across the NW Caribbean and portions of Central America providing scattered showers and tstms across the NW waters and interior portions of Nicaragua and Honduras this evening. Most of the activity remains W of 80W and is expected to move west of the area by Saturday night. A few isolated showers and tstms are occurring N of 16N between 75W-80W due to a weakening upper level low centered near 20N80W. Farther east... drier air aloft and mostly fair conditions prevail this evening within moderate to fresh trades. An approaching tropical wave currently along 56W will impact the Lesser Antilles on Saturday with increase cloudiness and a greater chance for isolated showers and tstms. Looking beyond this weekend however...Hurricane Irma looms across the central tropical Atlc and is forecast to approach 60W Tuesday night into Wednesday. ...HISPANIOLA... Mostly fair weather and clear skies prevail this evening across the island as dry air aloft moves in over the region. The overall dry weather pattern is expected to persist the next couple of days. ATLANTIC OCEAN... A middle to upper level trough is progressing over the mid-Atlc and SE CONUS regions this evening supporting a fairly divergent environment across the far western SW North Atlc waters this evening. Scattered showers and tstms are occurring generally N of 25N W of 79W...including interior portions of Florida... Georgia...and the Carolinas. Otherwise...a pair of 1020 mb highs centered near 25N72W and 31N70W are providing for fair conditions this evening. Farther east...an upper level low is centered near 24N54W and supports a stationary front extending from 32N53W SW to 27N60W to 26N67W. While isolated showers are occurring within 60 nm either side of the boundary...upper level divergence between the upper level low and an upper level anticyclone centered near 31N62W is generating an area of scattered showers and isolated tstms from 19N-27N between 55W-65W. Lastly...Hurricane Irma remains on the southern periphery of a ridge anchored by a 1029 mb high centered E of the Azores near 39N24W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN