000 AXNT20 KNHC 232331 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 731 PM EDT Sat Sep 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 1800 UTC surface analysis and satellite imagery through 2215 UTC. ...SPECIAL FEATURES... Hurricane Maria is centered near 26.3N 72.5W at 23/2100 UTC or about 248 nm E of Great Abaco Island and about 556 nm SSE of Cape Hatteras, North Carolina moving NNW at 8 kt. Estimated minimum central pressure is 950 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Scattered to numerous moderate convection is within 60 nm in the E semicircle, 90 nm in the SW quadrant and 135 nm in the NW quadrant. Scattered moderate convection is elsewhere within 210 nm in the N semicircle and 180 nm in the S semicircle. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details. Tropical Storm Lee is centered near 32.1N 49.8W at 23/2100 UTC or about 760 nm E of Bermuda and about 1173 nm W of the Azores moving NNW at 3 kt. Estimated minimum central pressure 1007 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate and isolated strong convection is within 105 nm of the center except 45 nm in the SE quadrant. See the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...TROPICAL WAVES... Tropical wave extends from 09N24W to 22N22W moving W at 5-10 kt. The wave coincides with a 700 mb low, the northern vortex, centered near 21N21W and associated 700 mb troughing between 16W- 28W. No significant deep convection is associated with the wave axis at this time. Ongoing deep convection remains S of the monsoon trough axis and will be mentioned below. Tropical wave extends from 05N57W to 16N56W moving W at 10-15 kt. The wave remains on the southwestern periphery of a 700 mb ridge anchored near 22N40W and lies beneath an upper level trough axis extending from 25N52W to a broad base deep in the tropics near 07N53W. Widely scattered moderate convection is N of 08N within 90 nm W of the tropical wave axis. ...ITCZ/MONSOON TROUGH... The monsoon trough axis extends from the African coast near 14N17W to 10N21W to 06N33W. The Intertropical Convergence Zone axis extends from 06N33W to 05N40W to 07N46W. Scattered moderate convection is from 06N-12N between 16W-25W and from 06N-11N between 48W-56W. ...DISCUSSION... GULF OF MEXICO... A middle to upper level low is noted on water vapor imagery centered over the Florida panhandle near 31N86W with a trough axis extending southward over the eastern Gulf to a broad base over the Yucatan peninsula and NW Caribbean Sea. An overall weak pressure pattern across the basin is resulting in gentle to moderate easterly winds with areas of isolated showers and tstms generally occurring from 23N-29N between 83W-88W under the influence of the middle to upper level lifting dynamics in place. W of 90W, dry and stable northerly flow aloft and generally gentle to moderate E-SE winds are providing for fair conditions and mostly clear skies this evening. Through the remainder of the weekend into the middle of next week, little change is expected in overall conditions. By Tuesday night into Wednesday, E-SE flow will increase slightly into moderate to occasional fresh breeze conditions as ridging noses in from the Arklatex region into the eastern Gulf Wednesday into Thursday. CARIBBEAN SEA... West-southwesterly flow aloft prevails W of 73W this afternoon as Hurricane Maria is well north of the basin and an overall weak pressure pattern remains in place across the central and western Caribbean. As a result of the weaker pressure pattern, winds remain generally light to gentle and variable at times. A couple of weak surface troughs are analyzed, one from the coast of central Cuba near 20N80W to the Gulf of Honduras near 16N87W, and the other extending south of Hispaniola near 18N72W to the La Guajira Peninsula in northern Colombia near 12N71.5W. Across the NW Caribbean, skies remain mostly clear with fair conditions prevailing this evening, except from western Cuba to the northern Yucatan Peninsula including the approach to the Yucatan Channel where isolated thunderstorms are occurring around an upper level trough to the N. To the east, the other surface trough is providing focus for widely scattered showers and tstms from 12N- 18N between 69W-72W. In addition, across the SW Caribbean, the monsoon trough axis extends along 08N/09N with scattered strong tstms occurring S of 12.5N between 72W-84W. Finally, a tropical wave currently along 57W will continue approaching the Lesser Antilles through Sunday and increase the probability of isolated showers and tstms. Otherwise, moderate to occasional fresh SE winds will prevail E of 70W. ...HISPANIOLA... A surface trough currently extends from the south-central coast near 18N72W to across the central Caribbean Sea, and continues to provide focus for scattered showers and tstms across the southeastern portion and south coast of the island this evening. The troughing will slide westward through Sunday as weak ridging builds in from the central Atlc from the east. ATLANTIC OCEAN... Outside the influence of Maria across the SW North Atlc waters, surface ridging prevails across much of the remainder of the central and eastern Atlc. A 1020 mb high is centered E-NE from Bermuda near 34N56W, and a 1021 mb high is centered across the central Atlc near 28N41W. Between these two highs, Tropical Storm Lee continues to influence the waters from 30N-34N between 48W-51W. In addition, a middle to upper level low is centered near 25N53W generating scattered showers and thunderstorms from 25N-32N between 39W-44W. For additional information please visit http://www.hurricanes.gov/marine $$ Lewitsky