Alert archive / Mississippi / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 752

August 8, 20118 counties in Arkansas; 18 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at Aug 8, 2011, 8:39 PM CDT for 8 counties in Arkansas; 18 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 8, 2011, 8:39 PM CDT (01:39 UTC)
Expired
Aug 9, 2011, 3:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 26 counties

Arkansas County, AR, Desha County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Monroe County, AR, Phillips County, AR, St. Francis County, AR, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Lafayette County, MS, Leflore County, MS, Marshall County, MS, Montgomery County, MS, Panola County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Yalobusha County, MS

The radar

The Memphis radar (KNQA), 126 km from the middle of the area, began a volume at 01:40 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
5%
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.

IssuedProductOfficeCountiesLasted
Aug 8, 8:45 PM CDTSevere Thunderstorm WarningLZKArkansas, Jefferson, Lonoke, Prairie30 min
Aug 8, 9:01 PM CDTSevere Thunderstorm WarningMEGLee, Phillips59 min
Aug 8, 9:07 PM CDTSevere Thunderstorm WarningMEGLee, Phillips38 min
Aug 8, 9:53 PM CDTSevere Thunderstorm WarningMEGPhillips36 min
Aug 8, 9:56 PM CDTSevere Thunderstorm WarningLZKJefferson, Lonoke34 min
Aug 8, 10:07 PM CDTSevere Thunderstorm WarningLZKArkansas, Jefferson, Lonoke, Prairie22 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

Little Rock, AR (KLZK), launched 00:00Z, 1.7 hours before the alert went out and 82 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, Little Rock, AR at 00:00Z on 2011-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4035 joules per kilogram.LCLLFCEL10008507005003002001001 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, Little Rock, AR at 00:00Z on 2011-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 132 square meters per square second.193958Sfc1 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
4035 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
1436 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
132 m²/s²
0-3 km storm-relative helicity
156 m²/s²
Significant tornado parameter
1.7
Supercell composite
12.0

Open this sounding in Storm Lab

The text

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

936 
WWUS20 KWNS 090138
SEL2
SPC WW 090138
ARZ000-MSZ000-090800-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 752
NWS STORM PREDICTION CENTER NORMAN OK
840 PM CDT MON AUG 8 2011

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

       EASTERN ARKANSAS
       NORTHWEST MISSISSIPPI

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 840 PM UNTIL
300 AM CDT.

HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES NORTHWEST OF
OXFORD MISSISSIPPI TO 55 MILES EAST OF MONTICELLO ARKANSAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 746...WW 747...WW
748...WW 750...WW 751...

DISCUSSION...TSTM CLUSTER IN E CNTRL AR HAS BECOME SOMEWHAT BETTER
ORGANIZED IN THE PAST HOUR...WITH COMPOSITE RADAR SHOWING A SIZABLE
AREA OF LOFTED HAIL.  COUPLED WITH HIGH PW OVER THE DOWNSTREAM DELTA
REGION AND 25+ KT WNWLY MID LVL FLOW...POTENTIAL WILL EXIST FOR
LOCALLY DMGG PRECIP-ENHANCED WINDS AS THE CLUSTER MOVES/DEVELOPS
GENERALLY ESE TO PERHAPS SEWD LATER TNGT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.
A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM MOTION
VECTOR 29025.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 8, 7:34 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 30 more116 min
Aug 8, 7:53 PM CDTSevere Thunderstorm WatchSPCBenton, Boone, Carroll, Crawford, Franklin, Johnson and 12 more7 hr
Aug 8, 11:00 PM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Clark, Cleburne, Cleveland and 32 more2 hr
Aug 8, 11:27 PM CDTMesoscale DiscussionSPCArkansas, Desha, Lee, Lincoln, Monroe, Phillips93 min
Aug 9, 2:21 AM CDTMesoscale DiscussionSPCArkansas, Benton, Carroll, Conway, Crawford, Faulkner and 26 more84 min
Aug 9, 1:20 PM CDTMesoscale DiscussionSPCClarke, Hinds, Jasper, Kemper, Lauderdale, Leake and 9 more115 min
Aug 9, 4:46 PM CDTSevere Thunderstorm WatchSPCGeorge, Greene, Perry, Stone, Wayne4 hr

Nearby

Severe Thunderstorm Watches in Mississippi, 2011Severe Thunderstorm Watches in Arkansas, 2011Every severe thunderstorm 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.