000 AXNT20 KNHC 191049 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON OCT 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0930 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 1014 MB LOW NEAR 09N23W TO 08N28W...THEN RESUMES IN THE VICINITY OF A 1014 MB LOW NEAR 13N30W TO A 1014 MB LOW NEAR 10N38W TO 09N42W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED 10N TO 15N BETWEEN 20W AND 25W. SCATTERED MODERATE CONVECTION IS NOTE FROM 06N TO 11N BETWEEN 33W AND 37W. ...DISCUSSION... GULF OF MEXICO... A MID TO UPPER LEVEL RIDGE IS BUILDING ACROSS THE CENTRAL PLAINS...FOLLOWING A BROAD UPPER TROUGH NOW MOVING THROUGH THE CANADIAN MARITIMES AND NW ATLC. THE MID TO UPPER RIDGE IS COMING INTO PHASE WITH A BROAD UPPER ANTICYCLONE PARKED OVER SOUTHERN MEXICO AND NORTHERN CENTRAL AMERICA. THIS IS RESULTING IN ZONAL FLOW ALOFT ACROSS THE GULF OF MEXICO...WHICH IN TURN IS ALLOWING A COLD FRONT MOVING ACROSS THE CENTRAL GULF TO WEAKEN AND SLOW. RECENT SURFACE OBSERVATIONS INDICATE THE TEMPERATURE AND MOISTURE GRADIENT ARE MORE SPREAD OUT ACROSS SOUTHERN AND CENTRAL FLORIDA...AND NO DISCERNIBLE GRADIENT IS EVIDENT OVER THE WESTERN GULF...SOUTH TEXAS OR NE MEXICO AT THIS TIME. SIMILARLY A LONG LIVED STATIONARY FRONT THAT HAD BEEN PLACE ACROSS THE BAHAMAS AND STRAITS OF FLORIDA HAS FINALLY BECOME DIFFUSE AS THE AIRMASSES MODIFY AND MIX OUT AHEAD OF THE NEARBY COLD FRONT. RICH DEEP LAYER MOISTURE SOUTH OF COLD FRONT ALONG WITH CONVERGENCE OF FRESH TO STRONG NE TO E FLOW IS SUPPORTING SCATTERED SHOWERS OVER SOUTH FLORIDA AND THE STRAITS OF FLORIDA. CONVERGENCE OF STRONG TO NEAR GALE FORCE NE WINDS IS ALSO SUPPORTING SCATTERED SHOWERS AND A FEW THUNDERSTORMS OVER THE FAR SW GULF OF MEXICO ALONG THE COAST BETWEEN CIUDAD DEL CARMEN TO COATZACOALCOS. MULTILEVEL CLOUDINESS PREVAILS ALONG AND SOUTH OF THE FRONT ELSEWHERE OVER THE SOUTHERN GULF...WITH CLEAR TO SCATTERED HIGH CLOUD OVER THE NORTHERN GULF. ASIDE FROM THE GALES OFF VERACRUZ...FRESH TO STRONG NE TO E WINDS PERSIST ACROSS THE GULF WITH 8 TO 12 FT OVER MUCH OF THE SW GULF AND 6 TO 9 FT ELSEWHERE. CARIBBEAN SEA... UPPER LEVEL RIDGING EXTENDS OVER CENTRAL AMERICA AND MUCH OF THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM OVER HONDURAS NE TO BEYOND THE WINDWARD PASSAGE. THE COMBINATION OF DIVERGENT FLOW ALOFT ASSOCIATED WITH THE UPPER ANTICYCLONE...CONVERGENCE OF MODERATE FRESH EAST FLOW...AND RICH DEEP LAYER MOISTURE ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER MAINLY THE NW CARIBBEAN. NO SIGNIFICANT CONVECTION IS NOTED ELSEWHERE ACROSS THE BASIN AT THIS TIME WHERE SUBSIDENT AND DRY NORTHERLY FLOW ALOFT CONTINUES BETWEEN THE UPPER ANTICYCLONE TO THE WEST AND A SHARP AND PERSISTENT UPPER TROUGH OVER THE FAR EASTERN CARIBBEAN. GENTLE TO MODERATE TRADES CONTINUE WITH ONLY OCCASIONAL FRESH BREEZE CONDITIONS EXPECTED WITHIN CLOSE PROXIMITY TO THE NW VENEZUELA AND COLOMBIA COASTS THROUGH THE MORNING. ...HISPANIOLA... NW TO N WINDS ALOFT PERSIST ACROSS HISPANIOLA BETWEEN AN UPPER ANTICYCLONE TO THE WEST AND A AN UPPER TROUGH TO THE EAST. WITH RELATIVELY HIGH DEEP LAYER MOISTURE IN PLACE...THIS PATTERN FAVORS LOW TOPPED AND FAST MOVING SHOWERS AND THUNDERSTORMS FAVORING THE HIGHLAND PORTIONS OF WESTERN DOMINICAN REPUBLIC AND EASTERN HAITI DURING THE AFTERNOON AND EVENING HOURS OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A BROAD MID/UPPER LEVEL TROUGH MOVING ACROSS THE NW ATLC IS PROVIDING SUPPORT TO A COLD FRONT EXTENDING FROM BERMUDA SW TO THE FLORIDA PENINSULA NEAR WEST PALM BEACH. IN ADDITION...A PRE- FRONTAL SURFACE TROUGH EXTENDS FROM 32N60W SW TO 25N68W. SCATTERED MODERATE SHOWERS AND THUNDERSTORMS ARE ONGOING WITHIN 150 NM E OF THE SURFACE TROUGH...WITH A FEW SHOWERS NOTED BETWEEN THE TWO BOUNDARIES. STRONG HIGH PRES IS BUILDING BEHIND THE FRONT OVER THE EASTERN UNITED STATES AND WESTERN ATLC...AND THE FRONT OVER THE WATERS NORTH OF THE BAHAMAS AND EAST OF NE FLORIDA. FARTHER EAST...AN UPPER LOW REMAINS ANCHORED NEAR 23N53W WITH A TROUGH EXTENDS SW ACROSS THE EASTERN CARIBBEAN. SW FLOW ALOFT ON THE EAST SIDE OF THIS TROUGH HAS BEEN SHEARING CONVECTION ACROSS A QUASI-STATIONARY SURFACE TROUGH REACHING FROM 16N55W TO WEAK 1014 MB LOW PRES CENTERED NEAR 11N53W. SCATTERED CONVECTION IS NOTED FROM 10N TO 15N BETWEEN 48W AND 51W. A DRY AIRMASS REMAINS IN PLACE ACROSS THE SUBTROPICAL ATLC WHERE A RIDGE ANCHORED BY A 1027 MB HIGH NEAR 33N40W DOMINATES N OF 18N BETWEEN 30W AND 40W. FARTHER EAST...A SHARP UPPER TROUGH REACHES FROM AN UPPER LOW OFF SOUTHERN PORTUGAL TO 16N40W. AN ASSOCIATED COLD FRONT IS PUSHING SOUTH ACROSS THE ATLC WATERS EAST OF 35W N OF 24N...ANCHORED BY A DEEP 999 MB LOW PRES AREA CENTERED UNDER THE UPPER LOW. STRONG NE WINDS OVER ARE NOTED BEHIND THE FRONT OVER THE ATLANTIC WATERS WEST OF MOROCCO...WITH STRONG TO NEAR GALE CONDITIONS BETWEEN THE CANARY ISLANDS AND MADEIRA. IN THE TROPICAL EASTERN ATLC...DIFFLUENT FLOW ALOFT TO THE SOUTHEAST OF THE UPPER TROUGH IS SUPPORTING A SERIES OF WEAK 1014 MB LOW PRES CENTERS ALONG THE MONSOON TROUGH NEAR 10N38W...12N30W...AND 09N23N. THESE FEATURES WILL REMAIN QUASI- STATIONARY THROUGH TODAY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ CHRISTENSEN