000 AXNT20 KNHC 282348 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST MON FEB 28 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED FROM SRN IVORY COAST NEAR 6N3W ALONG 3N11W 1N20W CROSSING THE EQUATOR NEAR 23W ALONG 1S32W 4S41W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS INLAND OVER IVORY COAST AND LIBERIA FROM 4N-8N BETWEEN 2W-10W. NUMEROUS STRONG CONVECTION IS ALSO FARTHER SW IN THE GULF OF GUINEA FROM 1N-4N BETWEEN 5E AND THE PRIME MERIDIAN. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 130 NM S OF THE AXIS BETWEEN 25W-33W. SIMILAR ACTIVITY IS ALSO S OF THE EQUATOR BETWEEN 39W-41W. STRONG ACTIVITY IS INLAND OVER COASTAL NE BRAZIL. ...DISCUSSION... THE GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT DRAPES ACROSS MUCH OF THE ERN CONUS CAUSING SEVERE WEATHER ACROSS PORTIONS OF THE SE UNITED STATES. THE FRONT ENTERS THE GULF NEAR SW LOUISIANA NEAR 30N93W EXTENDING SSW ALONG 26N95W 22N94W 20N97W. A SQUALL LINE IS OUT AHEAD OF THE FRONT INDICATED BY RADAR IMAGERY MOVING SWIFTLY ACROSS SRN ALABAMA AND THE FLORIDA PANHANDLE ALONG 31N87W TO 28N90W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 150 NM AHEAD OF THE COLD FRONT...BUT MAINLY JUST LOW-LEVEL CLOUDS ARE INDICATED BY SURFACE OBS AND SATELLITE IMAGERY. A FEW ISOLATED SHOWERS ARE AHEAD OF THE SQUALL LINE ACROSS NRN FLORIDA. BOTH AHEAD AND BEHIND THE FRONT...FAIR WEATHER AND CLEAR SKIES PREVAIL DUE TO A STRONG UPPER LEVEL RIDGE SITTING OVER THE NW CARIBBEAN PROVIDING DRY AIR ALOFT ACROSS THE BASIN. THE FRONTAL SYSTEM IS SUPPORTED BY A SHORTWAVE UPPER TROUGH N OF THE AREA ACROSS THE OHIO VALLEY. EXPECT THE FRONT TO CONTINUE MOVING SE ACROSS THE BASIN WITH POSSIBLE SHOWER ACTIVITY. THE CARIBBEAN SEA... MOSTLY FAIR WEATHER IS ACROSS THE CARIBBEAN TONIGHT INFLUENCED BY A STRONG UPPER LEVEL RIDGE CENTERED OVER THE NW CARIBBEAN NEAR 17N85W. WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE AND DRY AIR ACROSS THE BASIN. THE STRONG PRESSURE GRADIENT BETWEEN BROAD LOW PRESSURE ACROSS COLOMBIA AND HIGH PRESSURE ACROSS THE W ATLC IS SUPPORTING FRESH TO STRONG TRADE WINDS ACROSS MUCH OF THE BASIN WITH EMBEDDED ISOLATED SHOWERS. THE WINDS GAIN A CYCLONIC COMPONENT AROUND THE COAST OF COLOMBIA WHERE A 1008 MB LOW IS CENTERED OVER NRN COLOMBIA. ALSO...ISOLATED SHOWERS ARE POPPING UP JUST OFFSHORE OF COSTA RICA DUE TO THE STRONG WINDS BANKING AGAINST THE COASTLINE. EXPECT LITTLE CHANGE OVER THE NEXT 24 HRS. THE ATLANTIC OCEAN... THE UPPER LEVEL RIDGE CENTERED OVER THE NW CARIBBEAN EXTENDS OVER THE W ATLC SUPPORTING A 1025 MB SURFACE HIGH NEAR 28N64W. THE COMBINATION OF SURFACE RIDGING AND DRY AIR ALOFT IS PROVIDING MOSTLY FAIR CONDITIONS W OF 45W. AN UPPER LEVEL TROUGH COVERS THE CENTRAL ATLC BETWEEN 35W-45W SUPPORTING A SURFACE LOW PRESSURE SYSTEM. AN OCCLUDED 1011 MB LOW IS CENTERED NEAR 30N40W. A STATIONARY FRONT EXTENDS ALONG 30N36W 22N37W 13N43W WITH BECOMING A SHEAR LINE TO NE SOUTH AMERICA AND ACROSS THE NRN PORTIONS OF FRENCH GUIANA...SURINAME...AND GUYANA. A SURFACE TROUGH IS W OF THE FRONT ALONG 29N39W 23N40W 19N47W. ISOLATED SHOWERS ARE WITHIN 30 NM OF THE TROUGH AXIS. SCATTERED SHOWERS/THUNDERSTORMS ARE AHEAD OF THE TROUGH AND NEAR THE STATIONARY FRONT N OF 26N BETWEEN 34W-38W ENHANCED BY UPPER LEVEL DIFFLUENCE AROUND THE ERN SIDE OF THE UPPER TROUGH. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE STATIONARY FRONT AND SHEAR AXIS. THE E ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1035 MB HIGH NEAR 45N15W SUPPORTING BY AN UPPER LEVEL RIDGE ALONG 21W PROVIDING FAIR CONDITIONS ACROSS THIS PORTION OF THE BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ CW