000 AXNT20 KNHC 211154 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI OCT 21 2011 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 1030 UTC. ...SPECIAL FEATURE... REMNANT MOISTURE OVER THE W CARIBBEAN COUPLED WITH A SURFACE TROUGH THAT EXTENDS ALONG 79W/80W WITH A 1010 MB LOW ALONG THE TROUGH NEAR 14N ARE GENERATING CLUSTERS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 20N BETWEEN THE SURFACE TROUGH AND 85W. SURFACE PRESSURES ARE FALLING AND UPPER-LEVEL WINDS ARE EXPECTED TO BECOME MORE FAVORABLE FOR DEVELOPMENT. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N16W CONTINUING ALONG 10N21W TO 6N25W. A SURFACE TROUGH IS ANALYZED WITHIN THE TROPICS EXTENDING FROM 20N36W THROUGH A 1006 MB LOW NEAR 12N45W TO 10N47W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N-10N BETWEEN 10W-20W AND S OF 11N W OF 49W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 10N BETWEEN 42W-50W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-8N BETWEEN 23W-32W. THE ITCZ IS DISRUPTED BY THE ABOVE SURFACE TROUGH. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH DOMINATES THE GULF TO OVER S MEXICO AND THE YUCATAN CHANNEL ADVECTING A COOL/DRY AIRMASS OVER THE GULF WATERS IN WAKE OF THE RECENT FRONTAL PASSAGE. A SURFACE RIDGE COVERS THE GULF AND THE SE CONUS WITH A 1021 MB HIGH NEAR 26N91W AT 21/0900 UTC. SOME LINGERING COLD AIR STRATOCUMULUS CLOUDS ARE OVER THE SE GULF LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES TONIGHT. SURFACE RIDGE WILL CONTINUE TO BUILD ACROSS THE W GULF THROUGH TUE. CARIBBEAN SEA... THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS TO OVER THE YUCATAN CHANNEL WITH THE DRY AIR OVER THE GULF OF MEXICO EXTENDING INTO THE FAR NW CARIBBEAN N OF 19N W OF 85W. THE REMAINDER OF THE CARIBBEAN IS UNDER EASTERLY FLOW ALOFT. DRY STABLE AIR ALOFT COVERS THE E CARIBBEAN E OF 75W WITH SOME ISOLATED SHOWERS USHERED IN ON THE NE SURFACE FLOW. SURFACE LOW OVER THE SW CARIBBEAN WILL SLOWLY DRIFT W THROUGH THE WEEKEND. A SURFACE TROUGH WILL ENTER THE E CARIBBEAN MON AND THE CENTRAL CARIBBEAN TUE NIGHT. ATLANTIC OCEAN... THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS OVER THE W ATLC W OF 72W SUPPORTING A STATIONARY FRONT THAT AT 21/0900 UTC EXTENDS THROUGH 32N69W TO THE BAHAMA ISLANDS NEAR 23N75W AND A SURFACE TROUGH CONTINUING TO THE COAST OF CUBA NEAR 22N77W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 45 NM EITHER SIDE OF THE FRONT/TROUGH. COLD AIR STRATOCUMULUS CLOUDS ARE WITHIN 200 NM W OF THE FRONT/TROUGH. A SURFACE RIDGE IS BUILDING FROM THE N GULF OF MEXICO W TO THE FRONT. AN UPPER LOW COVERS THE REMAINDER OF THE W ATLC AND CENTRAL ATLC CENTERED NEAR 21N55W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-25N BETWEEN 50W-61W. A BROAD E/W UPPER RIDGE COVERS THE E ATLC AND THE TROPICAL S OF 30N E OF 50W WITH THE AXIS ALONG 13N/14N. A BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC N OF 25N E OF THE FRONT TO AFRICA. THE STATIONARY FRONT WILL DISSIPATE LATER TODAY. REMNANTS OF THE FRONT WILL DRIFT W TONIGHT THROUGH SUN. A SECOND COLD FRONT WILL MOVE SE ACROSS THE NW ATLC SUN NIGHT MERGING WITH THE FRONTAL TROUGH MON WITH THE MERGED FRONT EXTENDING FROM BERMUDA TO THE SE BAHAMAS MON NIGHT THEN MOVING INTO THE CENTRAL ATLC LATE TUE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW