000 AXNT20 KNHC 182346 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN OCT 18 2015 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... THE COMBINATION OF STRONG HIGH PRESSURE ACROSS EASTERN MEXICO... LOWER PRESSURE ACROSS CENTRAL AMERICA AND SOUTHERN MEXICO...AND A SURFACE TROUGH ANALYZED ACROSS THE SW GULF OF MEXICO WATERS IS SUPPORTING NEAR GALE TO GALE FORCE NW WINDS ALONG THE COAST OF VERACRUZ...MAINLY S OF 21N W OF 95W. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 FOR MORE DETAILS. ...TROPICAL WAVES... NONE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO A 1011 MB LOW NEAR 09N22W TO 07N25W...THEN RESUMES IN THE VICINITY OF A 1011 MB LOW NEAR 13N30W TO A 1012 MB LOW NEAR 10N39W TO 08N42W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 10N-14N BETWEEN 20W-25W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 03N-18N BETWEEN 20W-26W. ISOLATED MODERATE CONVECTION IS FROM 13N-17N BETWEEN 26W-30W...FROM 08N- 12N BETWEEN 33W-39W...AND FROM 07N-14N BETWEEN 42W-52W. TO THE WEST OF THE MONSOON TROUGH AXIS...A 1012 MB LOW IS CENTERED NEAR 11N53W WITH A SURFACE TROUGH EXTENDING NORTHWARD TO 17N54W. SCATTERED MODERATE CONVECTION IS FROM 11N-16N BETWEEN 48W-53W. ...DISCUSSION... GULF OF MEXICO... BROAD LONGWAVE TROUGHING IS NOTED ON WATER VAPOR IMAGERY OVER THE EASTERN CONUS AND WESTERN NORTH ATLC WATERS THIS EVENING SUPPORTING A COLD FRONT ANALYZED AT 18/2100 UTC FROM LAKE OKEECHOBEE TO 25N90W TO 23N94W. WHILE A RELATIVELY COOLER AND DRIER AIR MASS IS NOTED IN OBSERVATIONS TO THE NORTH OF THE FRONT...STRONG NE WINDS COVER MOST OF THE BASIN AS INDICATED BY EARLIER ASCAT PASSES. THIS WIND FIELD IS EXPECTED TO PERSIST THROUGH WEDNESDAY WITH WINDS SHIFTING MORE EASTERLY BY MONDAY AS HIGH PRESSURE TO THE NORTH ACROSS THE SE AND MID-ATLC SLIDES EASTWARD. ACROSS THE SW GULF...AS NOTED IN THE SPECIAL FEATURES SECTION...A 1008 MB LOW IS CENTERED ALONG THE MEXICO COAST NEAR 18N94W WITH A SURFACE TROUGH EXTENDING NW TO 22N97W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING MAINLY S OF 23N W OF 91W...WITH THE NEAR GALE TO GALE FORCE NW WINDS WITHIN CLOSE PROXIMITY TO THE COAST OF VERACRUZ. CARIBBEAN SEA... UPPER LEVEL RIDGING EXTENDS OVER CENTRAL AMERICA AND MUCH OF THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM OVER HONDURAS NE TO BEYOND 22N72W. GIVEN THE OVERALL DIFFLUENT ENVIRONMENT THE RIDGING PROVIDES...SCATTERED SHOWERS AND TSTMS...A FEW LOCALLY STRONG...ARE OCCURRING NW OF A LINE FROM THE WINDWARD PASSAGE NEAR 20N74W TO COASTAL NICARAGUA NEAR 12N84W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN CARIBBEAN ARE UNDER THE INFLUENCE OF NORTH-NORTHEASTERLY FLOW ALOFT BETWEEN THE RIDGE AND AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 17N59W SW TO A BASE OVER SOUTHERN VENEZUELA. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR AND SUBSIDENCE PREVAIL WITH CLEAR SKIES AND FAIR CONDITIONS THIS EVENING. A FEW LINGERING ISOLATED SHOWERS AND TSTMS ARE NOTED ACROSS HISPANIOLA AND THE LEEWARD ISLANDS BUT CONTINUE TO TREND DOWNWARD IN INTENSITY. FINALLY...GENTLE TO MODERATE TRADES CONTINUE WITH ONLY OCCASIONAL FRESH BREEZE CONDITIONS EXPECTED WITHIN CLOSE PROXIMITY TO THE NW VENEZUELA AND COLOMBIA COASTS THROUGH THE OVERNIGHT HOURS INTO MONDAY. ...HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS LINGER ACROSS THE ISLAND DUE TO A RELATIVELY DIFFLUENT ENVIRONMENT ALOFT AND PEAK DAYTIME HEATING. THIS ACTIVITY SHOULD DIMINISH GRADUALLY THROUGH THE OVERNIGHT HOURS LEAVING MOSTLY CLEAR SKIES AND FAIR CONDITIONS FOR EARLY MONDAY. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE WESTERN NORTH ATLC WATERS AND PORTIONS OF NEW ENGLAND THAT SUPPORT A COLD FRONT EXTENDING FROM 32N70W SW TO THE FLORIDA PENINSULA NEAR WEST PALM BEACH. IN ADDITION...A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 32N61W SW TO 24N73W. BETWEEN THESE TWO BOUNDARIES...ISOLATED SHOWERS ARE OCCURRING WITH MORE INTENSE ACTIVITY OF SCATTERED SHOWERS AND TSTMS WITHIN 150 NM EAST OF THE SURFACE TROUGH. OTHERWISE...BEHIND THE COLD FRONT STRONG N-NE WINDS PREVAIL AND WILL CONTINUE TO SPREAD SOUTHEASTWARD AS THE FRONT CONTINUE TO MARCH EASTWARD THROUGH MONDAY. ACROSS THE CENTRAL ATLC...AN UPPER LEVEL LOW AND MID- LEVEL ENERGY IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF 23N54W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 20N-25N BETWEEN 49W-59W. THIS CONVECTION IS FOUND ON THE SOUTHWESTERN PERIPHERY OF A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED NEAR 35N42W. FINALLY...ACROSS THE NORTHEASTERN PORTION OF THE DISCUSSION AREA...A COLD FRONT EXTENDS FROM 32N13W TO 27N21W TO 31N30W. OTHER THAN MODERATE TO FRESH NORTHERLY WINDS...ONLY A FEW ISOLATED SHOWERS ARE OCCURRING NE OF THE CANARY ISLANDS N OF 30N E OF 14W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN