000 AXNT20 KNHC 261723 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST MON NOV 26 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. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COAST OF GUINEA AT 10N14W TO 9N17W. THE ITCZ BEGINS AT 9N17W AND CONTINUES ALONG 7N30W 8N44W 7N59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N BETWEEN 19W-26W. SIMILAR ACTIVITY IS FROM 8N-11N BETWEEN 27W-39W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO...CARIBBEAN...AND WESTERN ATLC. THIS PATTERN IS PROVIDING MAINLY WESTERLY FLOW ALOFT ACROSS THE GULF WITH SOME SOUTHWESTERLY WINDS OVER THE WESTERN CARIBBEAN AS AN UPPER TROUGH APPROACHES. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH OVER GEORGIA. THE SURFACE RIDGE AXIS EXTENDS SOUTHWEST INTO THE GULF. LIGHT SE WINDS COVER THE EASTERN PORTIONS WITH THE WIND SPEED INCREASING UP TO 20 KT OVER THE WESTERN GULF WHERE MORE SOUTHERLY FLOW IS PRESENT. DRY AIR ALOFT IS KEEPING SKIES CLEAR ACROSS THE MAJORITY OF THE AREA EXCEPT FOR AN AREA OF SHOWERS OVER LOUISIANA NORTH OF 28N BETWEEN 88W-93W. THE SURFACE RIDGE IS EXPECTED TO MOVE EASTWARD ALLOWING A COLD FRONT TO PUSH INTO THE NW GULF TOMORROW. CARIBBEAN SEA... A BROAD UPPER LEVEL RIDGE COVERS THE CARIBBEAN CENTERED NEAR 14N75W. MOSTLY DRY AIR WRAPS AROUND THE RIDGE KEEPING MUCH OF THE AREA UNDER FAIR WEATHER. HOWEVER...A SMALL AREA OF MOIST DIFFLUENCE ALOFT AROUND THE WEST SIDE OF THE UPPER RIDGE IS HELPING PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 13N-16N BETWEEN 76W-82W WITH POSSIBLE ISOLATED SHOWERS CONTINUING NORTH TO 20N. A SURFACE TROUGH IS ALSO ANALYZED UNDER THIS AREA ALONG 18N80W TO 11N77W AS EASTERLY TRADEWIND FLOW OVER THE EASTERN CARIBBEAN CONVERGES WITH MORE NE WINDS OVER THE WESTERN CARIBBEAN. WINDS TO EITHER SIDE OF THE TROUGH REACH 20 KT WITH SOME STRONGER WINDS FARTHER SOUTH AND NEAR THE COAST OF COLOMBIA. THE SURFACE TROUGH IS EXPECTED TO MOVE NORTHWEST OVER THE NEXT COUPLE OF DAYS DRAWING SHOWERS/THUNDERSTORMS INTO THE NW CARIBBEAN AND ACROSS CENTRAL AMERICA. ATLANTIC OCEAN... ZONAL WESTERLY FLOW ALOFT COVERS THE WESTERN ATLC ACCOMPANIED BY DRY AIR. AT THE SURFACE...WEAK SURFACE RIDGING IS AROUND A 1024 MB HIGH NEAR 31N73W. THIS PATTERN IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE WEST ATLC. A NARROW UPPER LEVEL TROUGH EXTENDS INTO THE CENTRAL ATLC SUPPORTING A PAIR OF FRONTAL BOUNDARIES. FARTHEST WEST...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N52W AND CONTINUES ALONG 28N61W 26N68W WHERE IT DISSIPATES TO THE BAHAMAS TO 24N76W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. TO THE EAST...A STATIONARY FRONT EXTENDS ALONG 31N41W 27N45W 20N62W. SCATTERED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE AXIS. A WEAK UPPER RIDGE IS EAST OF THE SECOND FRONT WITH ANOTHER UPPER TROUGH COVERING THE FAR EASTERN ATLC FROM THE MADEIRA ISLANDS TO NEAR 10N40W. THIS UPPER TROUGH SUPPORTS A 1004 MB SURFACE LOW OVER THE CANARY ISLANDS NEAR 29N16W. A COLD FRONT ASSOCIATED WITH THE SYSTEM IS NOW OVER WEST AFRICA AND CONTINUES OVER WATER AS A DISSIPATING FRONT ALONG 21N17W TO 21N35W. A SURFACE TROUGH ALSO EXTENDS FROM THE LOW CENTER ALONG 26N19W 26N25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON