Alert archive / Arkansas / Tornado Watches in 2011

Tornado Watch 13

February 24, 20114 states

The Storm Prediction Center issued this tornado watch at Feb 24, 2011, 11:25 AM CST for 4 states. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Feb 24, 2011, 11:25 AM CST (17:25 UTC)
Expired
Feb 24, 2011, 8:00 PM CST
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 79 counties

Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleburne County, AR, Cleveland County, AR, Columbia County, AR, Conway County, AR, Crawford County, AR, Dallas County, AR, Faulkner County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Johnson County, AR, Lafayette County, AR, Little River County, AR, Logan County, AR, Lonoke County, AR, Madison County, AR, Miller County, AR, Montgomery County, AR, Nevada County, AR, Newton County, AR, Ouachita County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Searcy County, AR, Sebastian County, AR, Sevier County, AR, Stone County, AR, Union County, AR, Van Buren County, AR, Washington County, AR, White County, AR, Yell County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Adair County, OK, Choctaw County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Panola County, TX, Red River County, TX, Rusk County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Wood County, TX

The radar

The Western Arkansas radar (KSRX), 111 km from the middle of the area, began a volume at 17:25 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
70%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Feb 24, 3:26 PM CSTSevere Thunderstorm WarningLZKClark, Dallas, Garland, Hot Spring, Montgomery, Pike and 1 more49 min
Feb 24, 3:52 PM CSTSevere Thunderstorm WarningLZKConway, Faulkner, Garland, Perry, Pulaski, Saline53 min
Feb 24, 3:54 PM CSTFlash Flood WarningLZKCleburne, Conway, Independence, Izard, Sharp, Stone and 1 more3 hr
Feb 24, 3:54 PM CSTTornado WarningLZKFaulkner, Perry, Pulaski, Saline36 min
Feb 24, 4:05 PM CSTSevere Thunderstorm WarningLZKClark, Garland, Grant, Hot Spring, Jefferson, Lonoke and 2 more40 min
Feb 24, 4:26 PM CSTSevere Thunderstorm WarningLZKCleburne, Faulkner, Independence, Van Buren, White49 min
Feb 24, 4:37 PM CSTSevere Thunderstorm WarningLZKFaulkner, Lonoke, Prairie, Pulaski, White, Woodruff38 min
Feb 24, 4:38 PM CSTTornado WarningLZKLonoke, Pulaski, Saline37 min
Feb 24, 4:39 PM CSTSevere Thunderstorm WarningSHVBossier, Caddo66 min
Feb 24, 4:56 PM CSTSevere Thunderstorm WarningLZKArkansas, Jefferson, Lonoke, Monroe, Prairie, Pulaski and 1 more49 min
Feb 24, 5:00 PM CSTTornado WarningLZKLonoke, Prairie30 min
Feb 24, 5:07 PM CSTSevere Thunderstorm WarningLZKIndependence, Jackson, White38 min
Feb 24, 5:11 PM CSTSevere Thunderstorm WarningLZKJackson, Lonoke, Monroe, Prairie, White, Woodruff49 min
Feb 24, 5:16 PM CSTSevere Thunderstorm WarningSHVBienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 2 more59 min
Feb 24, 5:31 PM CSTSevere Thunderstorm WarningSHVColumbia, Union59 min
Feb 24, 5:59 PM CSTSevere Thunderstorm WarningSHVClaiborne, Lincoln, Union61 min
Feb 24, 6:09 PM CSTSevere Thunderstorm WarningLZKArkansas, Bradley, Cleveland, Desha, Drew, Jefferson and 1 more66 min
Feb 24, 6:12 PM CSTSevere Thunderstorm WarningSHVBienville, Jackson, Lincoln, Natchitoches, Red River, Winn48 min
Feb 24, 6:40 PM CSTSevere Thunderstorm WarningSHVCaldwell, Jackson, Lincoln, Ouachita, Union65 min
Feb 24, 6:59 PM CSTSevere Thunderstorm WarningSHVCaldwell, Jackson, LaSalle, Natchitoches, Winn61 min
Feb 24, 7:52 PM CSTSevere Thunderstorm WarningSHVHempstead, Howard, Sevier38 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

Shreveport, LA (KSHV), launched 12:00Z, 5.4 hours before the alert went out and 207 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-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2011-02-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 36 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2011-02-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 243 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
36 J/kg
Mixed-layer CIN
-228 J/kg
Mixed-layer LCL
741 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
243 m²/s²
0-3 km storm-relative helicity
282 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

258 
WWUS20 KWNS 241727
SEL3
SPC WW 241727
ARZ000-LAZ000-OKZ000-TXZ000-250000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 13
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CST THU FEB 24 2011

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

       A LARGE PART OF ARKANSAS
       PARTS OF NORTHERN LOUISIANA
       PASTS OF SOUTHEASTERN OKLAHOMA
       PARTS OF NORTHEAST TEXAS

EFFECTIVE THIS THURSDAY MORNING AND EVENING FROM 1125 AM UNTIL
600 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 100 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES NORTHWEST OF
RUSSELLVILLE ARKANSAS TO 25 MILES SOUTHEAST OF SHREVEPORT
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

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...THUNDERSTORMS ARE INCREASING IN NUMBER ACROSS ERN OK
INTO NERN TX AHEAD OF STRONG S/WV TROUGH AND DEVELOPING SURFACE LOW.
 WITH AIR MASS NOW FAVORABLY UNSTABLE AND NEARLY
UNCAPPED...POTENTIAL FOR SEVERE THUNDERSTORMS INCLUDING SUPERCELLS
WILL INCREASE EWD ACROSS THE WATCH THRU THE AFTERNOON.  E/W WARM
FRONT ACROSS CENTRAL AR WILL BE AN AREA FOR ENHANCED LOW LEVEL
SHEAR/SUPERCELL DEVELOPMENT.  TORNADOS WILL BE POSSIBLE WITH ANY
SUPERCELL THAT DEVELOPS.

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 24045.


...HALES

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 24, 10:34 AM CSTMesoscale DiscussionSPCGarland, Hempstead, Howard, Lafayette, Little River, Miller and 7 more56 min
Feb 24, 2:12 PM CSTMesoscale DiscussionSPCCrittenden, Cross, Lee, Mississippi, Phillips, Poinsett and 1 more93 min
Feb 24, 2:34 PM CSTTornado WatchSPCArkansas, Ashley, Chicot, Clay, Craighead, Crittenden and 14 more7 hr
Feb 24, 2:39 PM CSTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleburne, Cleveland, Columbia and 31 more66 min
Feb 24, 5:26 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 39 more94 min
Feb 23, 8:43 PM CSTMesoscale DiscussionSPCCraig, Nowata, Osage, Ottawa, Pawnee, Rogers and 1 more62 min
Feb 24, 3:07 AM CSTMesoscale DiscussionSPCAlfalfa, Beckham, Blaine, Caddo, Canadian, Custer and 17 more113 min
Feb 24, 4:10 AM CSTSevere Thunderstorm WatchSPCBeckham, Caddo, Canadian, Carter, Cleveland, Comanche and 17 more7 hr
Feb 24, 7:47 AM CSTMesoscale DiscussionSPCCleveland, Cotton, Garvin, Grady, Jefferson, McClain and 3 more118 min

Nearby

Tornado Watches in Arkansas, 2011Tornado Watches in Texas, 2011Tornado Watches in Louisiana, 2011Every 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.