000 AXNT20 KNHC 301734 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 30 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 1645 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COAST OF GUINEA-BISSAU AT 11N15W CONTINUING ALONG 9N22W 7N29W 8N35W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-9N BETWEEN 21W-32W. A WEAK SURFACE TROUGH IS JUST WEST OF THE END OF THE MONSOON TROUGH ALONG 14N37W TO 9N38W. A SECOND VERY WEAK SURFACE TROUGH IS FARTHER WEST ALONG 15N57W TO 11N57W. NEITHER TROUGH IS PRODUCING ANY CONVECTION. ...DISCUSSION... THE GULF OF MEXICO... A BROAD UPPER TROUGH CONTINUES TO COVER THE GULF OF MEXICO TODAY EXTENDING FROM THE NE CONUS ASSOCIATED WITH POST-TROPICAL STORM SANDY. DRY AIR IS WRAPPING AROUND THE UPPER TROUGH HELPING PROVIDE MOSTLY CLEAR SKIES ACROSS THE AREA. A SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA NEAR 26N81W TO 23N89W DEPICTING A WIND SHIFT DUE TO THE LARGE CYCLONIC CIRCULATION AROUND SANDY THAT STILL COVERS THE EASTERN GULF AND WESTERN ATLC. NORTH TO NORTHWEST WINDS UP TO 20 KT ARE PRESENT ACROSS THE EASTERN GULF BECOMING EAST TO SOUTHEAST UP TO 10 KT IN THE WESTERN GULF AROUND A SURFACE RIDGE THAT HAS BEGUN TO BUILD INTO THE AREA. A 1021 MB HIGH IS CURRENTLY ANALYZED OVER LOUISIANA AND IS EXPECTED TO MOVE SOUTH OVER THE NEXT 24 HOURS AS THE UPPER TROUGH LIFTS NORTH ALONG WITH SANDY. FAIR WEATHER IS EXPECTED TO CONTINUE ACROSS THE BASIN FOR AT LEAST THE NEXT 24 HOURS. THE CARIBBEAN SEA... NW SURFACE FLOW IS ACROSS THE NW CARIBBEAN BEHIND A COLD FRONT THAT IS PUSHING THROUGH THE NORTHERN CARIBBEAN. THE FRONT CURRENTLY EXTENDS FROM THE WEST ATLC ACROSS EASTERN CUBA TO NEAR 18N81W. POSSIBLE ISOLATED SHOWERS ARE NEAR THE FRONT AXIS. A LINE OF POSSIBLE SHOWERS ALSO EXTENDS FROM THE MONA PASSAGE TO NORTHERN COSTA RICA AHEAD OF THE FRONT. THE FRONT IS SUPPORTED BY A BROAD UPPER TROUGH COVERING THE EASTERN CONUS AND WEST ATLC PROVIDING MOSTLY SOUTHWEST FLOW ACROSS THE BASIN. SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO SPREADING OVER THE CENTRAL CARIBBEAN DUE TO BOTH MOIST SWLY FLOW ALOFT AND LOW-LEVEL CYCLONIC FLOW AROUND A SURFACE TROUGH EXTENDING FROM NEAR HISPANIOLA AT 18N68W TO NORTHERN COLOMBIA AT 12N72W. SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 12N-17N BETWEEN 68W-73W...AND FROM 9N-13N BETWEEN 73W-78W. FAIR WEATHER IS ACROSS THE EASTERN CARIBBEAN ASSOCIATED WITH DRY AIR ALOFT WRAPPING AROUND THE FAR WESTERN EDGE OF AN UPPER LEVEL RIDGE ACROSS THE TROPICAL ATLC. WEAK SURFACE RIDGING IS ALSO EXTENDING INTO THE AREA FROM A 1015 MB HIGH IN THE CENTRAL ATLC NEAR 22N60W. THE SURFACE TROUGH IN THE CENTRAL CARIBBEAN IS EXPECTED TO DRIFT WESTWARD OVER THE NEXT COUPLE DAYS AND WILL LIKELY INTERACT WITH THE FRONT TO PRODUCE SHOWERS/THUNDERSTORMS OVER THE SW CARIBBEAN. THE ATLANTIC OCEAN... CYCLONIC SURFACE FLOW IS STILL PRESENT ACROSS THE WEST ATLC AROUND POST-TROPICAL STORM SANDY TO THE NORTH. NOW THAT THE SYSTEM IS POST-TROPICAL WITH BAROCLINIC ENERGY...IT SUPPORTS A COLD FRONT THAT EXTENDS FROM THE NW ATLC INTO THE DISCUSSION AREA NEAR 32N69W TO THE CENTRAL BAHAMAS NEAR 24N75W AND CONTINUES INTO THE NORTHERN CARIBBEAN. A SURFACE TROUGH TRAILS BEHIND IT DEPICTING A SECOND WIND SHIFT BEHIND THE FRONT ALONG 32N75W TO SOUTH FLORIDA NEAR 26N81W. A PRE-FRONTAL TROUGH IS EAST OF THE FRONT ALONG 28N65W TO 23N70W. ISOLATED SHOWERS ARE WITHIN 50 NM EITHER SIDE OF THE PRE-FRONTAL TROUGH WITH POSSIBLE ISOLATED SHOWERS ALONG THE OTHER TWO BOUNDARIES.. AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC ALONG 60W SUPPORTING A WEAK SURFACE RIDGE AROUND A 1015 MB HIGH NEAR 22N60W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE CENTRAL ATLC. A WEAK SURFACE TROUGH IS TO THE SOUTH WITHIN THE TROPICAL ATLC ALONG 15N57W TO 11N57W WITH NO ASSOCIATED SHOWERS. FARTHER E...A BROAD UPPER TROUGH/LOW COVERS THE EAST ATLC SUPPORTING ANOTHER COLD FRONT THAT EXTENDS INTO THE AREA ALONG 32N18W TO 20N42W. A PRE-FRONTAL TROUGH IS ALONG 24N28W TO 17N37W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH AND THE SOUTHERN PORTION OF THE FRONT SOUTH OF 24N. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE FRONT TO THE NORTH OF 24N. SOME OF THIS ACTIVITY IS ASSOCIATED WITH AN UPPER LEVEL JET ON THE SOUTH SIDE OF THE UPPER LOW. UPPER LEVEL RIDGING COVERS THE TROPICAL ATLC SUPPORTING A WEAK 1014 MB HIGH OFF THE AFRICAN COAST NEAR 19N21W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON