Alert archive / Arkansas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 265

May 7, 201214 counties in Arkansas; McCurtain County, Oklahoma; Bowie County, Cass County, Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 7, 2012, 5:21 PM CDT for 14 counties in Arkansas; McCurtain County, Oklahoma; Bowie County, Cass County, Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
May 7, 2012, 5:21 PM CDT (22:21 UTC)
Expired
May 7, 2012, 10:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Calhoun County, AR, Clark County, AR, Columbia County, AR, Dallas County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Union County, AR, McCurtain County, OK, Bowie County, TX, Cass County, TX

The radar

The Shreveport radar (KSHV), 151 km from the middle of the area, began a volume at 22:22 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
30%
One or more gusts of 65 knots or more
20%
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

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

IssuedProductOfficeCountiesLasted
May 7, 5:30 PM CDTSevere Thunderstorm WarningSHVHempstead, Howard60 min
May 7, 5:40 PM CDTSevere Thunderstorm WarningLZKDallas50 min
May 7, 5:45 PM CDTSevere Thunderstorm WarningSHVLittle River, Sevier45 min
May 7, 6:22 PM CDTSevere Thunderstorm WarningSHVHempstead, Lafayette, Little River, Miller, Nevada53 min
May 7, 6:42 PM CDTSevere Thunderstorm WarningSHVLittle River63 min
May 7, 6:57 PM CDTSevere Thunderstorm WarningSHVColumbia, Lafayette, Miller63 min
May 7, 7:16 PM CDTSevere Thunderstorm WarningLZKOuachita25 min
May 7, 7:42 PM CDTSevere Thunderstorm WarningSHVBowie, Camp, Morris, Red River, Titus33 min
May 7, 8:17 PM CDTSevere Thunderstorm WarningSHVCamp, Cass, Morris, Titus, Upshur43 min
May 7, 8:38 PM CDTSevere Thunderstorm WarningLZKBradley, Calhoun, Cleveland, Dallas42 min
May 7, 8:50 PM CDTSevere Thunderstorm WarningSHVCass, Harrison, Marion, Morris, Upshur55 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, 10.4 hours before the alert went out and 148 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 2012-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 746 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, Shreveport, LA at 12:00Z on 2012-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -54 square meters per square second.1939Sfc1 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
746 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
1458 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-54 m²/s²
0-3 km storm-relative helicity
-19 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
May 7, 4:38 PM CDTMesoscale DiscussionSPCClark, Columbia, Hempstead, Howard, Lafayette, Little River and 5 more67 min
May 6, 9:55 PM CDTMesoscale DiscussionSPCCraig, Nowata, Ottawa, Washington65 min
May 7, 12:46 PM CDTSevere Thunderstorm WatchSPCBrewster, Brown, Callahan, Coke, Coleman, Concho and 23 more8 hr
May 7, 2:24 PM CDTMesoscale DiscussionSPCAndrews, Crane, Ector, Gaines, Loving, Midland and 3 more2 hr
May 7, 2:37 PM CDTMesoscale DiscussionSPCBandera, Blanco, Burnet, Concho, Gillespie, Kendall and 11 more83 min
May 7, 3:27 PM CDTSevere Thunderstorm WatchSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 30 more7 hr
May 7, 3:56 PM CDTSevere Thunderstorm WatchSPCAndrews, Culberson, Ector, Gaines, Jeff Davis, Loving and 4 more7 hr
May 7, 5:31 PM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Blanco, Burnet, Comal and 28 more89 min
May 7, 6:55 PM CDTMesoscale DiscussionSPCAndrews, Borden, Crane, Dawson, Ector, Gaines and 11 more95 min

Nearby

Severe Thunderstorm Watches in Arkansas, 2012Severe Thunderstorm Watches in Texas, 2012Severe Thunderstorm Watches in Oklahoma, 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.