A powerful upper level trough moved swiftly through the region during the morning and early afternoon hours of the 7th. A batch of rain mixed with snow changed to all snow on the Cumberland Plateau by late morning (around 10 am).
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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 HUN wrote it up.
A powerful upper level trough moved swiftly through the region during the morning and early afternoon hours of the 7th. A batch of rain mixed with snow changed to all snow on the Cumberland Plateau by late morning (around 10 am). The snow ended abruptly by early afternoon. Snowfall of a half inch or less occurred on grassy areas and elevated surfaces as temperatures remained near or just above freezing during the snowfall.
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 Huntsville, AL wrote its last area forecast discussion before the first event at Dec 7, 5:51 AM CST, 4 hours 9 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
551 AM CST WED DEC 7 2011
.UPDATE...
FOR 12Z TAFS.
&&
.AVIATION...
WILL CONTINUE WITH PERSISTENCE INVOLVING IFR CONDITIONS RELATED TO
LOW CLOUDS EXPECTED THROUGH MUCH OF THE FORECAST PERIOD FOR MSL AND
HSV. EXPECT -RASN TO MOVE INTO THE MSL AREA SHORTLY AFTER 12Z TIME
FRAME...WITH CHANGE OVER TO -SN EXPECTED BY AROUND 15Z...CONTINUING
INTO THE AFTERNOON. -SN CHANGE OVER AT HSV IS EXPECTED AROUND
19Z...WITH IFR CONDITIONS EXPECTED UNTIL AROUND 23Z AT MSL AND
SHORTLY AFTER 01Z AT HSV. MVFR VSBYS ARE EXPECTED UNTIL THE -SN ENDS.
&&
.PREV DISCUSSION... /ISSUED 315 AM CST WED DEC 7 2011/
DISCUSSION...MAIN FORECAST CONCERN THIS MORNING CENTERS ON THE PROB
FOR SOME WINTER TYPE PRECIP DEVELOPING LATER TODAY. LATEST MODEL
SUITES/BUFR SOUNDINGS/CRITICAL THICKNESS VALUES POINT TO A CHANGE
OVER IN PRECIP FROM LIGHT RAIN THIS MORNING...TO A LIGHT RAIN/SNOW
MIX LATE THIS MORNING...BEFORE TURNING PREDOM TO ALL SNOW LATER THIS
AFTERNOON. AXIS OF LIGHT RAIN GRADUALLY MOVING THROUGH THE CNTRL AND
ERN HALF OF THE AREA SHOULD CONTINUE NEWD INTO THE MORNING PERIOD.
HIGHLY AMPLIFIED/SHEARED UPPER TROUGH AXIS STRETCHING FROM THE SRN
PLAINS TO THE GREAT LAKES REGION WILL CONTINUE TO STRENGTHEN AS IT
BEGINS TO TRAVERSE ENEWD THROUGH THE REGION LATER TODAY. STRONG COLD
AIR ADVECTION ASSOCIATED WITH THE DEEPENING TROUGH PATTERN WILL ALSO
BEGIN TO STREAM INTO THE AREA FROM THE WNW LATER THIS MORNING...WITH
MAX TEMPS TODAY LIKELY OCCURRING AROUND DAYBREAK. PRECIP DEVELOPING
IN RESPONSE TO THE ONCOMING TROUGH AXIS WILL BEGIN TO OVERSPREAD THE
AREA FROM W TO E LATER THIS MORNING...WITH LIGHT RAIN TRANSITIONING
INTO A RAIN/SNOW MIX OR ALL SNOW HEADING INTO THE AFTERNOON PERIOD.
SFC WINDS WILL ALSO BE INCREASING OUT OF THE NW AROUND 15 MPH WITH
HIGHER GUSTS...ALLOWING FOR SOME RATHER COLD WIND CHILL READINGS.
WITH THE COLD AIR ADVECTION...OVERALL TEMPS SHOULD GRADUALLY FALL
THROUGH THE DAY...STARTING WITH THE LOW 40S THIS MORNING AND THEN
DECREASING INTO THE LOW/MID 30S RANGE LATE THIS AFTERNOON. THIS MAY
ALLOW FOR SOME LIGHT ACCUMULATION WITH THE DEVELOPING WINTER LIKE
PRECIP...WITH PERHAPS UP TO AN INCH POSSIBLE MAINLY ON GRASSY TYPE
SURFACES...AND 1 TO 2 INCHES DEVELOPING IN THE HIGHER LOCATIONS. AS
SUCH...HAVE GONE AHEAD AND EXPANDED THE WINTER WX ADVISORY TO COVER
THE ENTIRE FORECAST AREA STARTING AT 6 AM...AND CONTINUING THROUGH 3
PM IN THE WEST AND 6 PM FOR THE REMAINDER OF THE AREA. AREA ROADWAYS
SHOULD REMAIN FREE FROM ANY ICE THROUGHOUT THE DAY WITH TEMPS THIS
AFTERNOON REMAINING JUST ABOVE FREEZING. BLACK ICE IS CERTAINLY A
POSSIBILITY THOUGH THIS EVENING AND OVERNIGHT AS TEMPS QUICKLY FALL
BELOW FREEZING AFTER SUNSET. ANY LINGERING PRECIP THOUGH SHOULD BE
EXITING THE AREA TO THE E BY THE START OF THE EVENING PERIOD AS THE
UPPER TROUGH AXIS LIFTS TOWARD THE NE.
QUIET AND UNSEASONABLY COOL WX SHOULD THEN PREVAIL ACROSS THE AREA
STARTING THU AS HIGH PRESSURE BUILDS EWD ACROSS THE TN/OH VALLEY
REGIONS. HIGH PRESSURE STILL LOOKS TO BECOME REINFORCED ACROSS THE
MIDWEST REGION BY THE START OF THE WEEKEND PERIOD...WHICH SHOULD AID
IN MOD POLAR AIR REMAINING ENTRENCHED ACROSS THE TN VALLEY HEADING
INTO NEXT WEEK. THE LATTER HALF OF THE MODELS DO HINT AT THE SFC
RIDGE WEAKENING HEADING TOWARD MID WEEK...WITH GULF MOISTURE/LIGHT
SHOWERS RETURNING TO THE CNTRL GULF COAST REGION.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: CULLMAN...DEKALB...JACKSON...LIMESTONE...
MADISON...MARSHALL...MORGAN.
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: COLBERT...FRANKLIN AL...LAUDERDALE...LAWRENCE.
TN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: FRANKLIN TN...LINCOLN...MOORE.
&&
AVIATION...08
PREV DISCUSSION...09HAZARDOUS WEATHER OUTLOOK...CORRECTED NATIONAL WEATHER SERVICE HUNTSVILLE AL 804 AM CST WED DEC 7 2011 ALZ001>010-016-TNZ076-096-097-071900- LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN- MARSHALL-JACKSON-DEKALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN- 804 AM CST WED DEC 7 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH ALABAMA AND PORTIONS OF SOUTHERN MIDDLE TENNESSEE. .DAY ONE...TODAY AND TONIGHT... A MIXTURE OF LIGHT RAIN AND SNOW IS EXPECTED TO CHANGE OVER TO ALL SNOW BY THE LATE MORNING IN NORTHWEST ALABAMA AND BY EARLY AFTERNOON ACROSS NORTHEAST ALABAMA AND SOUTHERN MIDDLE TENNESSEE. A WINTER WEATHER ADVISORY IS IN EFFECT TODAY UNTIL 3 PM IN PORTIONS OF NORTHWEST ALABAMA AND UNTIL 6 PM ELSEWHERE IN NORTH ALABAMA AND SOUTHERN MIDDLE TENNESSEE. SNOW ACCUMULATIONS ARE EXPECTED TO BE GENERALLY UP TO ONE INCH...EXCEPT IN THE HIGHER ELEVATIONS OF NORTHEAST ALABAMA AND SOUTHERN MIDDLE TENNESSEE...WHERE AMOUNTS RANGING FROM ONE TO TWO INCHES ARE POSSIBLE. FOR MORE INFORMATION REGARDING THIS WINTER WEATHER EVENT...PLEASE REFER TO THE WINTER WEATHER ADVISORY THAT HAS BEEN ISSUED FOR THE TENNESSEE VALLEY. TEMPERATURES ARE EXPECTED TO REMAIN JUST ABOVE FREEZING...SO SIGNIFICANT TRAVEL CONCERNS ARE NOT EXPECTED DURING THE DAY. THE PRECIPITATION WILL END FROM THE WEST TO EAST BY EARLY THIS EVENING. HOWEVER...AS TEMPERATURES FALL INTO THE MID TO UPPER 20S TONIGHT... SOME BLACK ICE IS EXPECTED TO DEVELOP ON AREA ROADWAYS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY... NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER CALL TO ACTION STATEMENT... ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL IS NOT ANTICIPATED...BUT ANY TIMELY REPORTS OF SNOW TODAY WOULD BE GREATLY APPRECIATED. TT
The national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
A half inch or less of snowfall occurred on grassy and elevated surfaces atop Monte Sano Mountain. The air temperature was at or just above freezing during the time of snowfall.
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, December 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: 350694.