000 AXNT20 KNHC 090006 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 08 2014 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 2345 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN ATLANTIC ASSOCIATED WITH A 1011 MB LOW NEAR 10N21W EMBEDDED IN THE MONSOON TROUGH. THE AXIS OF THE WAVE EXTENDS FROM 14N21W TO THE LOW TO 8N21W...MOVING W AT 5-10 KT. A MIDDLE-LEVEL INVERTED TROUGH SUPPORTS THIS WAVE THAT IS ASSOCIATED WITH DEEP LAYER MOISTURE. A DIFFLUENT ENVIRONMENT ALOFT HAS BEEN SUPPORTING THE CONVECTION OF THIS WAVE THAT HAS DECREASED IN THE LAST COUPLE OF HOURS PARTLY DUE TO A STRONG DEEP LAYER ENVIRONMENTAL SHEAR. ISOLATED MODERATE CONVECTION IS FROM 6N-16N BETWEEN 20W-25W. A TROPICAL WAVE IS WITHIN 700 NM EAST OF THE LESSER ANTILLES WITH AXIS EXTENDING FROM 18N48W TO 6N49W...MOVING W AT 10-15 KT. MIDDLE TO UPPER LEVEL DRY AIR IS OBSERVED IN THE GOES-R AIRMASS PRODUCT W OF THE WAVE AXIS...AREA CURRENTLY DEVOID OF CONVECTION. HOWEVER...MIDDLE TO HIGH LEVEL CLOUDS ARE EAST OF THE AXIS WHERE DEEP LAYER MOISTURE AND A DIFFLUENT ENVIRONMENT ALOFT SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 8N-20N BETWEEN 40W-49W. A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 18N66W TO 11N69W...MOVING W AT 15 KT. SSMI TPW IMAGERY SHOW THE WAVE IS IN A MODERATE MOIST ENVIRONMENT IN THE LOWER TO MIDDLE LEVELS...HOWEVER STRONG DEEP LAYER ENVIRONMENTAL SHEAR IN THIS REGION OF THE BASIN INHIBITS THE DEVELOPMENT OF DEEP CONVECTION. ISOLATED SHOWERS AND TSTMS ARE SW OF PUERTO RICO FROM 17N-18N WITHIN 60 NM W OF THE AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 14N17W SW TO A 1011 MB SURFACE LOW NEAR 10N21W AND THEN CONTINUES ALONG 8N30W TO 11N38W. THE ITCZ EXTENDS FROM 10N39W TO 10N48W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES AND SURFACE LOW...SCATTERED MODERATE CONVECTION IS FROM 5N-14N BETWEEN 26W- 40W. ...DISCUSSION... GULF OF MEXICO... SURFACE RIDGING DOMINATES ACROSS THE BASIN BEING ANCHORED BY A 1018 MB HIGH IN THE NE GULF NEAR 29N84W AND SUPPORTED BY A MIDDLE LEVEL ANTICYCLONE CENTERED NEAR 28N94W. THE RIDGE IS PROVIDING E-SE WINDS OF 5-15 KT N OF 22N AS WELL AS SUPPORTING STABLE WEATHER CONDITIONS. IN THE SW GULF...A MIDDLE-LEVEL INVERTED TROUGH SUPPORTS A SURFACE TROUGH ALONG 23N92W TO 16N94W...WHICH IS ENHANCING ISOLATED SHOWERS AND TSTMS WITHIN 160 NM W OF THE TROUGH. FAIR WEATHER IS ELSEWHERE BEING SUPPORTED BY DRY AIR SUBSIDENCE. SURFACE RIDGING AND FAIR WEATHER WILL DOMINATE ACROSS THE BASIN THE NEXT THREE DAYS. CARIBBEAN SEA... ABUNDANT DEEP LAYER MOISTURE IS IN A PORTION OF THE NW AND SW CARIBBEAN COLOCATED WITH A BROAD AREA OF DIVERGENT FLOW IN THE UPPER LEVELS. THESE TWO FACTORS ALONG WITH INSTABILITY PROVIDED BY THE PASSAGE OF A TROPICAL WAVE CURRENTLY ALONG 92W SUPPORT SCATTERED MODERATE TO ISOLATED STRONG CONVECTION S OF 20N W OF 80W. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL-EASTERN CARIBBEAN WITH AXIS ALONG 68W. SEE THE TROPICAL WAVE SECTION ABOVE FOR DETAILS. AN ELONGATED MIDDLE TO UPPER LEVEL TROUGH NE OF PUERTO RICO SUPPORT A SURFACE TROUGH THAT EXTENDS FROM THE ATLC ALONG THE LESSER ANTILLES FROM 16N61W TO 13N61W...THUS ENHANCING SHOWERS THIS REGION OF THE ANTILLES. OTHERWISE...ISOLATED SHOWERS AND TSTMS ARE WITHIN 40 NM OF EASTERN CUBA. THE REMAINDER BASIN IS BEING INFLUENCED BY STRONG DEEP LAYER ENVIRONMENTAL SHEAR AND DRY AIR SUBSIDENCE...THUS SUPPORTING FAIR WEATHER. TRADES OF 10 TO 15 KT DOMINATE ACROSS THE REGION DUE TO A RELAXED PRESSURE GRADIENT. THE NEXT TROPICAL WAVE WILL ENTER THE EASTERN BASIN SATURDAY MORNING WHILE THE FORMER WAVE MOVES ACROSS THE CENTRAL-WESTERN BASIN. ...HISPANIOLA... CLOUDINESS AS WELL AS ISOLATED SHOWERS AND TSTMS ARE ACROSS THE CENTRAL AND WESTERN ISLAND BEING SUPPORTED BY SHALLOW MOISTURE AND A ZONE OF MIDDLE LEVEL DIFFLUENCE. SIMILAR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH FRIDAY NIGHT AS A BROAD REGION OF MOISTURE CURRENTLY E OF THE LESSER ANTILLES CONTINUES TO MOVE WESTWARD. ATLANTIC OCEAN... MIDDLE TO UPPER LEVEL RIDGING DOMINATES IN THE SW N ATLC...THUS SUPPORTING A SURFACE RIDGE IN THAT REGION OF THE BASIN. FARTHER EAST...AN ELONGATED MIDDLE TO UPPER LEVEL LOW CONTINUE TO SUPPORT A SURFACE TROUGH ALONG 22N61W S TO THE CENTRAL-SOUTHERN LESSER ANTILLES NEAR 13N61W. A DIFFLUENT ENVIRONMENT GENERATED BY A MIDDLE TO UPPER LEVEL TROUGH E OF THE ELONGATED LOW SUPPORT A REGION OF SCATTERED HEAVY SHOWERS AND TSTMS FROM 15N-25N BETWEEN 50W-60W. OTHERWISE...TWO TROPICAL WAVES ARE IN THE CENTRAL AND EASTERN ATLC. SEE WAVES SECTION ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR