000 AXNT20 KNHC 222345 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 744 PM EDT Sun Oct 22 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 cold front is currently analyzed across the NW Gulf waters from the SW coast of Louisiana near 30N93W to the Texas coast near Corpus Christi. The front is forecast to sweep across the Gulf through Monday night with near gale to gale force N to NW winds expected to materialize S of 21N W of 95W by 23/1800 UTC and persist for 12 hours as the pressure gradient remains strong. Please see the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...TROPICAL WAVES... A tropical wave extend from 06N51W to 17N48W moving W at 5-10 kt. The wave coincides with 700 mb troughing between 42W-52W and a maximum in 850 mb relative vorticity to the east of the axis near 11N47W. Scattered moderate convection is from 07N-17N between 38W-50W and continues to be enhanced by a middle to upper level trough with axis extending from 25N40W SW to a broad base over northern Guyana. A tropical wave extend from 10N89W to 20N89W moving W at 10-15 kt. The wave coincides with 700 mb troughing between 84W-94W and a maximum in 850 mb relative vorticity along the wave axis near 18N. Scattered moderate convection is from 12N-23N between 85W-92W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 10N14W to 08N20W. The Intertropical Convergence Zone axis extends from 08N20W to 04N40W to 06N50W. Isolated moderate convection is from 03N-06N between 13W-18W. ...DISCUSSION... GULF OF MEXICO... A vigorous middle to upper level trough is progressing eastward over the lower Mississippi River valley this evening and supports a cold front extending from the Arklatex region to the SW Louisiana coast near 30N93W to the Texas coast near Corpus Christi then inland across northern Mexico. A leading outflow boundary extends east of the cold front from 30N90W to 28N92W to 27N97W. Low-level moisture convergence and middle to upper level divergence is generating scattered showers and tstms primarily across the eastern Gulf waters N of 25N between 82W-90W. Additional isolated showers are occurring N of 25N W of 90W. Farther south...the northern extent of a tropical wave along 90W is providing focus for scattered showers and tstms S of 24N between 83W-96W. Most of this convection is also enhanced due to upper level divergence on the northern periphery of an upper level ridge centered over the NW Caribbean Sea near 20N85W. Otherwise... the cold front is expected to sweep across the basin through Tuesday. As the front passes across the western Gulf...the Special Features near gale to gale force winds are anticipated within a broader fresh to strong northerly wind field that will spread eastward in wake of the front. Strong high pressure will settle in across the southern Plains and move out across the western Gulf by Wednesday night into Thursday. CARIBBEAN SEA... The combination of a tropical wave along 90W...a surface trough extending from the Gulf of Honduras SW to the offshore waters of Nicaragua near 12N83W...and a favorable upper level divergent environment over much of the western Caribbean anchored near 19N84W are supportive of scattered showers and strong tstms occurring W of a line from western Cuba through 17N80W to northern Colombia coast near 11N74W...including much of Central America. Most of the western Caribbean falls within moderate to fresh trades while farther east...fresh to strong trades prevail as a strong pressure gradient remains in place due to strong high pressure anchored across the western North Atlc. ...HISPANIOLA... Dry air aloft within NW flow will support fair weather across the island through Monday. Fresh to strong trades are expected through Monday night and will diminish into moderate to occasional fresh levels on Tuesday. ATLANTIC OCEAN... Much of the SW North Atlc is under the influence of a surface ridge anchored by 1034 mb high centered over the Canadian Maritimes near 47N64W. The southern periphery of this ridge is providing moderate to fresh E-SE winds W of 65W. Farther east...an upper level low is centered near 26N64W. In addition...a longwave trough over the central North Atlc is supporting a cold front from 32N45W SW to 30N50W then becomes a stationary front to near the upper level low around 28N63W. Scattered showers and isolated tstms are occurring within 150 nm either side of the front...and from 22N-30N between 60W-66W in association with the upper level low. The remainder of the eastern Atlc is under the influence of another surface ridge anchored by a 1030 mb high centered W of the Iberian peninsula near 40N14W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN