Alert archive / Mississippi / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 547

August 1, 201214 counties in Alabama; 41 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at Aug 1, 2012, 3:02 PM CDT for 14 counties in Alabama; 41 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 1, 2012, 3:02 PM CDT (20:02 UTC)
Expired
Aug 1, 2012, 8:47 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
65 kt
All 55 counties

Colbert County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Marion County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Alcorn County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clarke County, MS, Clay County, MS, Covington County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Itawamba County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Lee County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pontotoc County, MS, Prentiss County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Webster County, MS, Winston County, MS, Yazoo County, MS

The radar

The Columbus AFB radar (KGWX), 61 km from the middle of the area, began a volume at 20:03 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 1, 3:08 PM CDTSevere Thunderstorm WarningMEGLee, Pontotoc29 min
Aug 1, 3:14 PM CDTSevere Thunderstorm WarningMEGAlcorn, Tippah31 min
Aug 1, 3:35 PM CDTSevere Thunderstorm WarningJANClay, Oktibbeha, Webster39 min
Aug 1, 3:45 PM CDTSevere Thunderstorm WarningMEGItawamba, Lee, Prentiss45 min
Aug 1, 4:06 PM CDTSevere Thunderstorm WarningHUNColbert, Lauderdale39 min
Aug 1, 4:10 PM CDTSevere Thunderstorm WarningJANClay26 min
Aug 1, 4:20 PM CDTSevere Thunderstorm WarningMEGMonroe26 min
Aug 1, 4:25 PM CDTSevere Thunderstorm WarningMEGCalhoun, Chickasaw, Pontotoc50 min
Aug 1, 4:36 PM CDTSevere Thunderstorm WarningMEGCalhoun, Chickasaw, Lafayette, Pontotoc39 min
Aug 1, 4:43 PM CDTSevere Thunderstorm WarningJANLowndes47 min
Aug 1, 4:53 PM CDTSevere Thunderstorm WarningMEGCalhoun, Chickasaw, Pontotoc33 min
Aug 1, 4:56 PM CDTSevere Thunderstorm WarningJANChoctaw, Winston49 min
Aug 1, 4:58 PM CDTSevere Thunderstorm WarningHUNLauderdale26 min
Aug 1, 5:33 PM CDTFlash Flood WarningJANChoctaw, Winston117 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 12:00Z, 8.0 hours before the alert went out and 163 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 12:00Z on 2012-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1994 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 12:00Z on 2012-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
1994 J/kg
Mixed-layer CIN
-151 J/kg
Mixed-layer LCL
1606 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
-28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 2:36 PM CDTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 5 more54 min

Nearby

Severe Thunderstorm Watches in Mississippi, 2012Severe Thunderstorm Watches in Alabama, 2012Every severe thunderstorm watch in 2012

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.