000 AXNT20 KNHC 161743 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI NOV 16 2012 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. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH GUINEA TO NEAR 10N16W WHERE IT TRANSITIONS INTO THE ITCZ ALONG 10N24W 9N30W 10N37W 11N44W. IT CONTINUES ON THE WEST SIDE OF A SURFACE TROUGH ALONG 11N50W TO 10N62W. THE SURFACE TROUGH IS ALONG 16N45W 12N46W. AN UPPER LEVEL TROUGH OVER THE EASTERN ATLC IS HELPING PRODUCE A WIDE AREA OF CONVECTION NEAR THE ITCZ AND TO THE NORTH OF IT. IT IS ALSO SUPPORTING A SECOND SURFACE TROUGH JUST NORTH OF THE ITCZ ALONG 20N34W TO 12N39W. SCATTERED MODERATE CONVECTION IS FROM 9N-16N BETWEEN 19W-35W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 8N-12N BETWEEN 35W-41W. ISOLATED MODERATE CONVECTION IS FROM 11N-12N BETWEEN 42W-45W...AND FROM 10N-12N BETWEEN 48W-52W. ...DISCUSSION... THE GULF OF MEXICO... MAINLY NORTHWESTERLY FLOW ALOFT COVERS THE GULF OF MEXICO BETWEEN AN UPPER LEVEL RIDGE OVER MEXICO AND AN UPPER LEVEL TROUGH MOVING THROUGH THE EASTERN CONUS WITH AXIS THAT EXTENDS JUST WEST OF THE FLORIDA PENINSULA ALONG 84W. THE UPPER TROUGH CONTINUES TO SUPPORT A STATIONARY FRONT EAST OF FLORIDA WHICH EXTENDS TO THE SOUTHERN TIP OF FLORIDA WHERE IT TRANSITIONS INTO A SURFACE TROUGH INTO THE SE GULF ALONG 25N80W TO 23N86W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 90 NM OF THE AXIS. A SECOND SURFACE TROUGH IS IN THE SW GULF ALONG 25N96W TO 19N94W...ALSO REMNANTS OF THE FRONTAL BOUNDARY EAST OF FLORIDA. SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE AXIS. THE CENTRAL GULF IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT BETWEEN THE TWO UPPER LEVEL FEATURES. THE UPPER RIDGE IS SUPPORTING SURFACE RIDGING TO THE NORTH WHICH IS BUILDING SOUTH INTO THE GULF AND IS PROVIDING NORTHEAST TO EAST SURFACE FLOW OF 10-15 KT ACROSS THE BASIN. SURFACE RIDGING IS EXPECTED TO CONTINUE ACROSS THE GULF WITH MOISTURE REMAINING IN THE SW GULF AND SPREADING INTO THE SE GULF FROM THE WEST ATLC NEAR THE CURRENT FRONTAL BOUNDARY. THE CARIBBEAN SEA... THE UPPER LEVEL TROUGH OVER THE FAR EASTERN GULF CONTINUES INTO THE NW CARIBBEAN ACCOMPANIED BY DRY AIR ALOFT...WHICH IS HELPING PROVIDE FAIR CONDITIONS ACROSS THIS AREA. HOWEVER...DIFFLUENCE ALONG WITH MOIST SOUTHWESTERLY FLOW ALOFT BETWEEN THE UPPER TROUGH AN UPPER LEVEL RIDGE COVERING THE EASTERN CARIBBEAN ALONG 65W IS HELPING SUPPORT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM THE SW CARIBBEAN TO HISPANIOLA BETWEEN 70W-80W. A FEW OF THE SHOWERS/THUNDERSTORMS IN THE SW CARIBBEAN ARE ALSO ENHANCED BY THE MONSOON TROUGH WHICH EXTENDS ALONG 9N INTO NORTHERN COLOMBIA. THE EASTERN CARIBBEAN IS EXPERIENCING MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT AROUND THE EAST SIDE OF THE UPPER RIDGE ALONG 65W. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... AN UPPER LEVEL TROUGH COVERING THE EASTERN CONUS SUPPORTS A STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N75W AND CONTINUES TOWARDS FLORIDA AND PARALLELS THE COASTLINE ALONG 27N80W TO 26N80W WHERE IT CONTINUES AS A SURFACE TROUGH INTO THE FLORIDA STRAITS. ISOLATED SHOWERS/THUNDERSTORMS ARE ALONG THE AXIS. DIFFLUENCE ALOFT BETWEEN THE UPPER TROUGH AND AN UPPER LEVEL RIDGE TO THE EAST ALONG 65W IS HELPING PRODUCE SCATTERED SHOWERS/THUNDERSTORMS FROM EASTERN CUBA TO NEAR 24N68W. A SURFACE TROUGH IS TO THE EAST ALONG 29N63W TO 22N64W PRODUCING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 90 NM EITHER SIDE OF THE AXIS AS WELL AS FROM 23N-25N BETWEEN 57W-60W. THE UPPER LEVEL RIDGE ALONG 65W FEEDS INTO A LARGER UPPER RIDGE OVER THE N CENTRAL ATLC WHICH SUPPORTS A BROAD SURFACE RIDGE ANCHORED BY A 1032 MB HIGH NEAR 40N38W PROVIDING FAIR CONDITIONS ACROSS THIS AREA. AN UPPER LEVEL TROUGH EXTENDS FROM AN UPPER LOW WEST OF PORTUGAL TO NEAR 20N45W AND THEN EXTENDS SOUTHWARD ALONG 45W. THIS NARROW UPPER TROUGH IS HELPING SUPPORT A LARGE AREA OF SHOWERS/THUNDERSTORMS IN THE EASTERN TROPICAL ATLC AS DESCRIBED IN THE ITCZ SECTION. THE UPPER LOW IS ALSO SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N12W TO 29N25W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE FRONT AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON