000 AXNT20 KNHC 131747 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI NOV 13 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N10W 6N20W 6N30W 8N38W 6N48W 7N60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 9W-14W. SIMILAR ACTIVITY IS FROM 4N-12N BETWEEN 17W-21W...AND FROM 9N-12N BETWEEN 21W-27W. AN EMBEDDED SURFACE TROUGH IS ANALYZED FROM 12N34W TO 7N37W. SHOWER ACTIVITY IS SHEARED TO THE E OF THE TROUGH AXIS. SCATTERED MODERATE CONVECTION IS FROM 7N-14N BETWEEN 44W-54W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE CONTINUES TO BUILD ACROSS THE GULF OF MEXICO FROM THE N ANCHORED BY A 1016 MB HIGH OVER W MISSISSIPPI NEAR 32N91W PROVIDING GENERALLY FAIR WEATHER ACROSS THE BASIN. MAINLY LIGHT NLY SURFACE WINDS COVER THE AREA E OF 91W. IN THE UPPER LEVELS...A NARROW SHORTWAVE TROUGH EXTENDS FROM S FLORIDA TO THE BAY OF CAMPECHE INTO CENTRAL MEXICO. SIGNIFICANT DRY AIR AND SUBSIDENCE IS OVER MUCH OF THE BASIN OBSERVED IN WATER VAPOR IMAGERY PROVIDING STABLE CONDITIONS TO THE AREA. AREAS OF STRATOCUMULUS CLOUDS ARE ALSO OVER MUCH OF THE BASIN NOTED ON VISIBLE SATELLITE IMAGERY. EXPECT THE SURFACE RIDGE TO DRIFT E AS SE RETURN FLOW DEVELOPS OVER THE WRN GULF AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST MON AFTERNOON. CARIBBEAN SEA... AS OF 1500 UTC...A STATIONARY FRONT EXTENDS FROM THE W ATLC ACROSS ERN CUBA NEAR 21N77W INTO THE NW CARIBBEAN TO 19N81W. A PRE-FRONTAL SURFACE TROUGH SE OF THE FRONT EXTENDS FROM 21N76W TO 16N79W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM SE OF THE TROUGH AXIS. AN UPPER LEVEL TROUGH CENTERED OFF THE COAST OF VIRGINIA SUPPORTS THE FRONT AND SURFACE TROUGH. SCATTERED SHOWERS/THUNDERSTORMS ARE OVER THE SW CARIBBEAN S OF 11N BETWEEN 76W-84W IN ASSOCIATION WITH SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ. A BROAD UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE CARIBBEAN ALONG WITH MODERATELY DRY AIR ALOFT BESIDES A SWATH OF UPPER LEVEL MOISTURE NEAR THE FRONTAL SYSTEM. NW TO N WINDS OF 20-25 KT TRAIL BEHIND THE FRONT REACHING 30 KT NEAR THE COAST OF NICARAGUA. MODERATE TRADE WINDS PREVAIL ACROSS THE ERN CARIBBEAN. ATLANTIC OCEAN... AS OF 1500 UTC...A STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N70W ALONG 26N73W ACROSS THE CENTRAL BAHAMAS TO ERN CUBA NEAR 21N77W. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED TO THE E ALONG 31N68W 26N71W ACROSS THE ERN BAHAMAS TO ERN CUBA NEAR 21N76W. SCATTERED SHOWERS/THUNDERSTORMS ARE TO THE E OF THE TROUGH FROM 23N-32N BETWEEN 63W-68W. THE FRONT/TROUGH ARE SUPPORTED BY AN UPPER LEVEL TROUGH COVERING THE W ATLC CENTERED OFF THE COAST OF VIRGINIA NEAR 34N74W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE TO THE W EXTENDING FROM THE LEEWARD ISLANDS TO NEAR 29N53W IS SUPPORTING THE SHOWER ACTIVITY E OF THE TROUGH AXIS. THIS UPPER DIFFLUENT ZONE IS ALSO SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS FROM 19N-29N BETWEEN 56W-69W. TO THE E...A COLD FRONT BRUSHES THE NRN BORDER OF THE DISCUSSION AREA FROM A 1009 MB LOW NEAR 32N35W ALONG 30N42W TO 32N52W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 100 NM OF THE FRONT AXIS. THE FRONT IS SUPPORTED BY A SHORTWAVE UPPER TROUGH WITH AXIS ALONG 48W. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ERN ATLC ANCHORED BY A 1020 MB HIGH NEAR 26N31W. IN THE UPPER LEVELS...A BROAD UPPER RIDGE COVERS THE TROPICAL ATLC WHILE A SHORTWAVE UPPER LEVEL TROUGH EXTENDS FROM S OF THE CANARY ISLANDS TO W OF THE CAPE VERDE ISLANDS. THIS UPPER LEVEL TROUGH IS SHEARING MOISTURE FROM THE ITCZ TO THE NE SUPPORTING CLOUDINESS AND POSSIBLE ISOLATED SHOWERS SE OF A LINE FROM 12N30W TO 20N16W. $$ WALTON