Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 674

April 30, 20115 counties in Arkansas; 14 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2011, 9:26 PM CDT for 5 counties in Arkansas; 14 counties in Texas. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2011, 9:26 PM CDT (02:26 UTC)
Expired
Apr 30, 2011, 10:30 PM CDT
In force
64 min
Issued by
the Storm Prediction Center

Counties Hempstead County, AR, Howard County, AR, Little River County, AR, Miller County, AR, Sevier County, AR, Bowie County, TX, Camp County, TX, Cass County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Marion County, TX, Morris County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 103 km from the middle of the area, began a volume at 02:29 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.

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 2.4 hours before the alert went out and 109 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 00:00Z on 2011-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3108 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 00:00Z on 2011-05-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 170 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
3108 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
891 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
170 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
2.3
Supercell composite
13.1

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 7:49 PM CDTMesoscale DiscussionSPCClay, Greene, Izard, Lawrence, Randolph, Sharp and 1 more56 min
Apr 30, 8:47 PM CDTMesoscale DiscussionSPCArkansas, Clark, Conway, Faulkner, Garland, Grant and 12 more58 min
Apr 30, 11:39 PM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Conway, Craighead, Cross and 31 more66 min
May 1, 1:16 AM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Conway, Craighead, Crittenden and 37 more59 min
May 1, 3:50 AM CDTMesoscale DiscussionSPCLee, Monroe, Phillips2 hr
May 1, 8:30 AM CDTMesoscale DiscussionSPCClark, Dallas, Garland, Hempstead, Hot Spring, Howard and 9 more30 min
May 1, 8:45 AM CDTSevere Thunderstorm WatchSPCClark, Columbia, Dallas, Garland, Hempstead, Hot Spring and 10 more6 hr
May 1, 12:12 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 34 more93 min
May 1, 12:47 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 27 more8 hr
May 1, 3:18 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more87 min
May 1, 5:42 PM CDTMesoscale DiscussionSPCClark, Dallas, Garland, Grant, Hempstead, Hot Spring and 14 more3 hr
May 1, 5:43 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more92 min
May 1, 1:14 AM CDTMesoscale DiscussionSPCBosque, Brown, Callahan, Coleman, Collin, Comanche and 28 more2 hr
May 1, 1:40 AM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 31 more7 hr
May 1, 3:19 AM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Collin, Comanche and 38 more86 min
May 1, 4:45 AM CDTTornado WatchSPCAnderson, Bowie, Camp, Cass, Cherokee, Delta and 21 more4 hr
May 1, 7:29 AM CDTMesoscale DiscussionSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 34 more91 min

Nearby

Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Arkansas, 2011Every mesoscale discussion 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.