000 AXNT20 KNHC 241708 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 107 PM EDT Tue Oct 24 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 1700 UTC. ...SPECIAL FEATURES... A cold front crosses the Gulf waters from 27N82W SW to 24N85W to 20N92W to SE Mexico near 18N94W. Near gale NW to N winds are occurring in the vicinity of Veracruz Mexico or S of 21N W of 95W. Winds in this area are expected increase to minimal gale force this afternoon as reinforcing cold air pushes southward behind the cold front from Texas through the SW Gulf waters. As the high pressure builds southward over NE Mexico and South Texas it will begin to weaken and reduce the pressure gradient over the southern Gulf. This will allow gale force winds to decrease to strong by Wed evening. Winds in this area will decrease further to light on Thu. Please see the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...TROPICAL WAVES... A tropical wave just to the E of the Lesser Antilles has an axis extending from 16N59W to 07N60W, moving W around 10 kt. A strong mid to upper-level trough extending SSW from 30N61W to just east of puerto Rico near 18N65W to the coast of Venezuela near 10N63W is interacting with the tropical wave. The trough is subjecting the wave to strong vertical wind shear, but upper-level divergence on the east side of the trough is triggering scattered moderate and isolated strong convection mainly to the east of the tropical wave axis from 07N to 19N between 50W and 62W. The wave is expected to continue weakening as it moves slowly west through the high shear environment. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from Guinea Bissau on the African coast near 12N15W to 10N20W. The Intertropical Convergence Zone axis continues from 10N20W to 06N30W to 05N43W to 09N58W. Aside from the convection associated with the tropical wave, scattered moderate and isolated strong convection is present within 180 nm either side of a line from 05N23W to 09N50W. ...DISCUSSION... GULF OF MEXICO... A deep mid to upper-level trough progressing eastward through the Mississippi Valley continues to support a cold front extending SW from just south of Tampa Florida near 27N82W to 24N85W to SE Mexico near 18N94W. Upper-level convergence over the Gulf is limiting deep convection to the moist air along and to the east of the front over the SE Bay of Campeche. Cloudiness and isolated showers are found along and up to 60 nm NW of the cold front. Otherwise, a surface ridge building over the NW Gulf in the wake of the front is supporting near gale force winds over the SW Gulf. See the Special Features section for more details. A secondary reinforcing cold front is frontalizing over the NW Gulf. The added shot of cold air will increase the northerly winds across much of the basin tonight and Wednesday. Strong high pressure in wake of the front will build SE over Texas and the NW on Thursday, then slide eastward to northern Florida by Fri morning. CARIBBEAN SEA... An upper level anticyclonic circulation is centered over the NW Caribbean near the Gulf of Honduras. This high continues to provide upper-level divergence which supports scattered showers and isolated tstms over the NW Caribbean. The sustained convection has induced surface troughing from the Gulf of Honduras to western Cuba. Otherwise, a weakening tropical wave is expected to push slowly eastward from the Lesser Antilles into the eastern Caribbean and produce showers and thunderstorms. A cold front currently bisecting the the Gulf of Mexico will across the Yucatan channel into the NW Caribbean Wed morning, then stall south of Cuba on Thu. Fresh to strong N winds will channel between the front and the Yucatan Wed night and Thu morning before the front weakens. ...HISPANIOLA... Very dry convergent N flow aloft to the west of an upper-level trough will support fair weather across the island through Wed night as moderate to fresh trades prevail. ATLANTIC OCEAN... Scattered showers and tstms are occurring over the far NW forecast waters, or NW of a line from 32N74W to 26N80W. The front will move SE across the Bahamas to near the Turks and Caicos islands by Fri morning as it weakens and stalls. Farther east, an upper- level trough has induced a surface trough extending from 26N58W to 21N63W. Scattered showers and isolated tstms associated with the trough are occurring from 22N to 28N between 51W and 61W. This area of convection lies to the SW of a frontal boundary extending WSW from 32N34W to 27N46W to 28N53W. This boundary has no significant convection associated with it. Otherwise, broad surface ridging anchored by 1030 mb high pressure centered over the NW Atlc near 39N59W dominates the remainder of the basin. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy