Outflow boundaries from a Mesoscale Convective System over Arkansas pushed into Mississippi and aided in diurnally driven convection. Outflows from this activity allowed thunderstorm development to spread eastward into west Central Alabama by late afternoon.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BMX wrote it up.
Outflow boundaries from a Mesoscale Convective System over Arkansas pushed into Mississippi and aided in diurnally driven convection. Outflows from this activity allowed thunderstorm development to spread eastward into west Central Alabama by late afternoon. Isolated thunderstorms across the area resulted in isolated wind damage.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Birmingham, AL wrote its last area forecast discussion before the first event at Aug 24, 5:59 PM CST, 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BIRMINGHAM AL 659 PM CDT WED AUG 24 2011 .UPDATE... AVIATION DISCUSSION. && .DISCUSSION... A MCS CURRENTLY MOVING SOUTH ACROSS ARKANSAS AND LOUISIANA IS PUSHING OUTFLOW BOUNDARIES INTO EAST CENTRAL MISSISSIPPI. THESE BOUNDARIES ARE SPARKING SHOWERS AND THUNDERSTORMS IN THIS AREA. PW VALUES ACROSS MISSISSIPPI ARE AROUND 1.8...PROVIDING PLENTY OF MOISTURE. OUTFLOW BOUNDARIES ARE KICKING OUT OF THE SHOWERS AND THUNDERSTORM AND MOVING INTO EXTREME WESTERN ALABAMA ALLOWING SHOWER AND THUNDERSTORMS TO DEVELOP THERE AS WELL. PW VALUES ACROSS THE EASTERN 2/3 OF THE CWA DO NOT SUPPORT CONVECTION...THEREFORE SHOWERS AND THUNDERSTORMS SHOULD STAY CONFINED TO THE EXTREME WESTERN PORTION OF THE CWA. ANY SHOWER OR THUNDERSTORM THAT DEVELOPS SHOULD DISSIPATE BEFORE MIDNIGHT. OTHERWISE...THE RIDGE OF HIGH PRESSURE CONTINUES OVER THE WESTERN PORTION OF THE US...WITH A TROF OVER THE GREAT LAKES. THEREFORE NORTHWESTERLY FLOW CONTINUES TO PUMP DRY AIR INTO THE AREA. A COLD FRONT CURRENTLY STRETCHING FROM WISCONSIN TO MISSOURI SHOULD MOVE SOUTHWARD OVERNIGHT AND MOVE INTO CENTRAL ALABAMA ON THURSDAY. THERE DOES NOT APPEAR TO BE ENOUGH OF A LIFTING MECHANISM TO ALLOW SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE FRONT....AND MOISTURE VALUES SHOULD REMAIN RELATIVELY LOW. SO HAVE KEPT SLIGHT CHANCE POPS IN ACROSS THE AREA THROUGH FRIDAY...SINCE CONFIDENCE IS LOW AS TO HOW MUCH...IF ANY...RAIN THE CWA MIGHT RECEIVE. THE FRONT WILL CLEAR THE AREA BY FRIDAY...LEAVING TEMPS SLIGHTLY COOLER BEHIND THE FRONT. HOWEVER TEMPS SHOULD RECOVER QUICKLY...WITH DRY CONDITIONS AIDING IN THE RISING TEMPERATURES. NORTHWESTERLY FLOW WILL CONTINUE THROUGH NEXT WEEK...LEAVING VERY LOW CHANCES OF RAIN. HIGH TEMPERATURES WILL RUN A FEW DEGREES ABOVE NORMAL THROUGH THE PERIOD...HOWEVER WITH THE DRY AIR IN PLACE...DON'T FORESEE ANY HEAT INDEX VALUE CONCERNS. && .AVIATION... 00Z TAF DISCUSSION. A FEW ISOLATED SHOWERS AND STORMS HAVE DEVELOPED EARLY THIS EVENING...BUT THEY ARE NOT EXPECTED TO LAST MUCH LONGER. THIS ACTIVITY SHOULD SUBSIDE BY 02Z. OTHERWISE...NOT EXPECTING ANY PROBLEMS TONIGHT OR TOMORROW AS VFR CONDITIONS WILL PREVAIL. 10/ARM && .BMX WATCHES/WARNINGS/ADVISORIES... NONE. && 73/10
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BIRMINGHAM AL 722 PM CDT WED AUG 24 2011 ALZ011>015-017>050-260030- MARION-LAMAR-FAYETTE-WINSTON-WALKER-BLOUNT-ETOWAH-CALHOUN- CHEROKEE-CLEBURNE-PICKENS-TUSCALOOSA-JEFFERSON-SHELBY-ST. CLAIR- TALLADEGA-CLAY-RANDOLPH-SUMTER-GREENE-HALE-PERRY-BIBB-CHILTON- COOSA-TALLAPOOSA-CHAMBERS-MARENGO-DALLAS-AUTAUGA-LOWNDES-ELMORE- MONTGOMERY-MACON-BULLOCK-LEE-RUSSELL-PIKE-BARBOUR- 722 PM CDT WED AUG 24 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE COUNTIES SERVED BY THE NATIONAL WEATHER SERVICE OFFICE IN BIRMINGHAM. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT IS NOT EXPECTED AT THIS TIME.
The Birmingham radar (KBMX), 76 km away, was scanning. The volume nearest the first event began at 00:21 UTC.
1 thunderstorm wind. Local standard time, as filed.
A couple trees were knocked down around the Lake Tuscaloosa area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alabama in 2011Every state in 2011This day in weather historyWarnings in Alabama, August 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 345221.