000 AXNT20 KNHC 022255 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 654 PM EDT Sat Sep 2 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 2215 UTC. ...SPECIAL FEATURES... Hurricane Irma is centered near 18.5N 44.6W at 02/2100 UTC or about 985 nm E of the Leeward Islands moving W at 13 kt. Estimated minimum central pressure is 973 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Scattered to numerous moderate convection is within 75 nm of center. Widely scattered moderate convection is elsewhere from 16N-21N between 41W-48W. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends from 08N27W to 15N31W moving W at 10 kt. The wave coincides with 700 mb troughing between 24W-34W and a maximum in 850 mb relative vorticity in the vicinity of a 1012 mb low centered along the monsoon trough near 08N26W. Isolated moderate convection is from 03N-12N between 23W-31W. A tropical wave extends from 11N66W to 21N63W moving W at 5-10 kt. The wave coincides with broad 700 mb troughing between 60W- 70W and continues to move SW and away from influence of an upper level low associated troughing to the N-NE near 25N58W. Isolated moderate convection is from 17N-21N between 61W-64W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 13N17W to 11N22W to 07N30W. Widely scattered moderate convection is from 05N-09N between 10W-22W. ...DISCUSSION... GULF OF MEXICO... Water vapor imagery indicates a middle to upper level trough extending from over SE CONUS to a base over the SW Gulf near 22N94W. The troughing supports a stationary front extending across southern Georgia and the Florida panhandle to near 29N90W in the north-central waters. A pre-frontal surface trough extends from the front near 30N86W to 23N91W. 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 showers and isolated tstms generally E of 87W with stronger tstms activity noted in the Tampa Bay region and across the SE waters S of 24N between 80W-88W...including the Yucatan Channel region. Upper level divergence is also maximized over the SW Gulf and along with a surface trough from 18N94W to 21N96W...these features are providing focus for scattered showers and tstms S of 23N between 86W-97W...including much of the Yucatan peninsula and southern Mexico. Otherwise...outside of ongoing convection...mostly light to gentle winds are noted as a weak ridge axis extends across the NW Gulf anchored by a 1018 mb high centered across the lower Mississippi River valley. CARIBBEAN SEA... Water vapor imagery indicates most moisture remains W of 81W with scattered showers and strong tstms occurring across interior portions of Central America from Honduras southward to Panama...where the monsoon trough axis extends along 10N...and across the Yucatan peninsula...northern Guatemala...and southern Mexico N of 16N. A few isolated showers and tstms are occurring elsewhere across the region. Farther east...drier air aloft prevails E of 81W...with only a few isolated showers and tstms occurring N of 17N between Jamaica to the Mona Passage. A tropical wave extends along 65W and will continue to impact the Greater Antilles through Sunday night into Monday. Looking beyond this weekend...Hurricane Irma looms across the central tropical Atlc and is forecast to approach 60W Tuesday night into early Wednesday. ...HISPANIOLA... Isolated showers and tstms are expected to continue through the overnight hours into Sunday as a tropical wave approaches from the east...currently along 65W. The wave is expected to pass west of the island by late Monday with conditions gradually improving into Tuesday. 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 27N W of 74W...including interior portions of Florida...and the coastal area of the Carolinas. Otherwise...weak ridging extends from near Bermuda SW to the central Bahamas providing for mostly fair conditions this evening. Farther east...an upper level low is centered near 26N58W and supports a stationary front extending from 32N56W SW to 25N65W. While isolated showers are occurring within 75 nm either side of the boundary N of 29N...upper level divergence between the upper level low and an upper level anticyclone centered near 29N66W is generating an area of scattered showers and isolated tstms from 21N-29N between 55W- 71W. Lastly...Hurricane Irma remains on the southwestern periphery of a ridge anchored by a 1027 mb high centered S-SE of the Azores near 34N32W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN