Alert archive / Arkansas / Tornado Watches in 2011

Tornado Watch 190

April 23, 201115 counties in Arkansas; Dunklin County, Pemiscot County, Missouri

The Storm Prediction Center issued this tornado watch at Apr 23, 2011, 8:19 PM CDT for 15 counties in Arkansas; Dunklin County, Pemiscot County, Missouri. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 23, 2011, 8:19 PM CDT (01:19 UTC)
Expired
Apr 24, 2011, 12:00 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt

Counties Baxter County, AR, Clay County, AR, Craighead County, AR, Fulton County, AR, Greene County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Lawrence County, AR, Marion County, AR, Newton County, AR, Randolph County, AR, Searcy County, AR, Sharp County, AR, Stone County, AR, Dunklin County, MO, Pemiscot County, MO

The radar

The Little Rock radar (KLZK), 155 km from the middle of the area, began a volume at 01:21 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
30%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 23, 8:26 PM CDTSevere Thunderstorm WarningMEGRandolph49 min
Apr 23, 8:42 PM CDTTornado WarningLZKMarion, Newton, Searcy48 min
Apr 23, 8:59 PM CDTSevere Thunderstorm WarningMEGDunklin31 min
Apr 23, 9:11 PM CDTSevere Thunderstorm WarningMEGClay, Randolph49 min
Apr 23, 9:26 PM CDTTornado WarningLZKBaxter, Marion, Searcy, Stone24 min
Apr 23, 9:33 PM CDTFlash Flood WarningMEGClay, Randolph5 hr
Apr 23, 10:25 PM CDTFlash Flood WarningLZKBaxter, Boone, Marion, Newton, Searcy3 hr
Apr 23, 10:26 PM CDTSevere Thunderstorm WarningMEGClay34 min
Apr 23, 11:22 PM CDTSevere Thunderstorm WarningMEGPemiscot38 min
Apr 23, 11:52 PM CDTFlash Flood WarningMEGClay, Greene3 hr
Apr 23, 11:52 PM CDTSevere Thunderstorm WarningMEGClay, Greene, Randolph38 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

Springfield, MO (KSGF), launched 00:00Z, 1.3 hours before the alert went out and 197 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, Springfield, MO at 00:00Z on 2011-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Springfield, MO at 00:00Z on 2011-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
747 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
283 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

205 
WWUS20 KWNS 240118
SEL0
SPC WW 240118
ARZ000-MOZ000-240500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 190
NWS STORM PREDICTION CENTER NORMAN OK
820 PM CDT SAT APR 23 2011

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

       PARTS OF NORTHERN ARKANSAS
       MISSOURI BOOTHEEL

EFFECTIVE THIS SATURDAY NIGHT FROM 820 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 2.5 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 30 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 15 MILES SOUTH OF HARRISON
ARKANSAS TO 55 MILES EAST NORTHEAST OF JONESBORO ARKANSAS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU0).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 187...WW 189...

DISCUSSION...SUPERCELL HAS DEVELOPED ALONG E/W BOUNDARY ACROSS NRN
AR.  WITH FAVORABLE SHEAR AND INSTABILITY...CONDITIONS WILL BE
FAVORABLE FOR TORNADOS AS THE STORM CONTINUES EWD ACROSS THE WATCH.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 27030.


...HALES

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 23, 8:09 PM CDTMesoscale DiscussionSPCBaxter, Boone, Clay, Cleburne, Conway, Craighead and 25 more2 hr
Apr 23, 10:40 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Fulton and 8 more95 min
Apr 24, 11:58 AM CDTMesoscale DiscussionSPCBaxter, Clay, Cleburne, Conway, Craighead, Faulkner and 19 more62 min
Apr 24, 12:27 PM CDTTornado WatchSPCBaxter, Clay, Cleburne, Conway, Craighead, Fulton and 16 more7 hr
Apr 24, 3:31 PM CDTMesoscale DiscussionSPCCleburne, Craighead, Greene, Independence, Izard, Jackson and 9 more59 min
Apr 24, 5:34 PM CDTMesoscale DiscussionSPCCrawford, Franklin, Madison, Polk, Scott, Sebastian and 1 more26 min
Apr 24, 5:36 PM CDTTornado WatchSPCConway, Crawford, Franklin, Garland, Johnson, Logan and 8 more7 hr
Apr 24, 6:23 PM CDTMesoscale DiscussionSPCBaxter, Clay, Cleburne, Conway, Craighead, Faulkner and 32 more2 hr
Apr 24, 3:01 PM CDTMesoscale DiscussionSPCMississippi, New Madrid, Scott89 min

Nearby

Tornado Watches in Arkansas, 2011Tornado Watches in Missouri, 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.