Alert archive / Alabama / Tornado Watches in 2011

Tornado Watch 895

November 22, 201134 counties in Alabama; 20 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Nov 22, 2011, 11:58 AM CST for 34 counties in Alabama; 20 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: Nov 22, 2011, 11:58 AM CST (17:58 UTC)
Expired: Nov 22, 2011, 8:00 PM CST
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 54 counties

Autauga County, AL, Barbour County, AL, Bibb County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Russell County, AL, Shelby County, AL, Sumter County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, Clarke County, MS, Covington County, MS, Forrest County, MS, Greene County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Leake County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Perry County, MS, Scott County, MS, Smith County, MS, Wayne County, MS, Winston County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 157 km from the middle of the area, began a volume at 18:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 10%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Nov 22, 12:30 PM CST	Severe Thunderstorm Warning	JAN	Neshoba, Newton, Winston	45 min
Nov 22, 1:03 PM CST	Severe Thunderstorm Warning	JAN	Kemper, Lauderdale, Lowndes, Noxubee, Winston	57 min
Nov 22, 1:27 PM CST	Severe Thunderstorm Warning	BMX	Greene, Pickens, Sumter	48 min
Nov 22, 1:57 PM CST	Severe Thunderstorm Warning	MOB	Choctaw	63 min
Nov 22, 2:13 PM CST	Severe Thunderstorm Warning	BMX	Greene, Hale, Marengo, Pickens, Sumter, Tuscaloosa	47 min
Nov 22, 5:46 PM CST	Severe Thunderstorm Warning	MOB	Butler, Covington, Crenshaw	44 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 6.0 hours before the alert went out and 166 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 559 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 476 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 216 m²/s²
0-3 km storm-relative helicity: 252 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

446 
WWUS20 KWNS 221758
SEL5
SPC WW 221758
ALZ000-MSZ000-222300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 895
NWS STORM PREDICTION CENTER NORMAN OK
1200 PM CST TUE NOV 22 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       WESTERN AND CENTRAL ALABAMA
       EASTERN MISSISSIPPI

EFFECTIVE THIS TUESDAY AFTERNOON FROM NOON UNTIL 500 PM CST.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTH NORTHWEST OF
PINE BELT MISSISSIPPI TO 35 MILES EAST NORTHEAST OF SELMA
ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...A LINE OF THUNDERSTORMS OVER CENTRAL MS HAS INTENSIFIED
AND ACCELERATED DURING THE PAST HOUR...AND WILL TRACK ACROSS THE
WATCH AREA DURING THE NEXT FEW HOURS.  STRONG WINDS ALOFT AND
MESOSCALE ORGANIZATION OF LINE WILL POSE A THREAT OF DAMAGING WINDS.
 ALSO...ISOLATED DISCRETE CELLS FORMING AHEAD OF THE LINE MAY BECOME
SUPERCELLULAR WITH A RISK OF DAMAGING WINDS OR ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 26035.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 22, 11:38 AM CST	Mesoscale Discussion	SPC	Autauga, Bibb, Butler, Chilton, Choctaw, Clarke and 18 more	37 min
Nov 22, 12:49 PM CST	Mesoscale Discussion	SPC	Blount, Cherokee, DeKalb, Etowah, Jackson, Marshall	116 min
Nov 22, 2:40 PM CST	Mesoscale Discussion	SPC	Autauga, Bibb, Butler, Chilton, Choctaw, Clarke and 13 more	65 min
Nov 22, 3:24 PM CST	Mesoscale Discussion	SPC	Barbour, Bullock, Chambers, Clay, Dale, Elmore and 8 more	2 hr
Nov 22, 10:26 AM CST	Mesoscale Discussion	SPC	Adams, Amite, Copiah, Franklin, Jefferson, Jefferson Davis and 7 more	94 min

Nearby

Tornado Watches in Alabama, 2011 Tornado Watches in Mississippi, 2011 Every tornado watch in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.