Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 681

May 1, 201115 counties in Arkansas; 4 counties in Oklahoma; 34 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 1, 2011, 8:30 AM CDT for 15 counties in Arkansas; 4 counties in Oklahoma; 34 counties in Texas. It was in force for 30 min.

The area

The outline as issued.

The facts

Issued: May 1, 2011, 8:30 AM CDT (13:30 UTC)
Expired: May 1, 2011, 9:00 AM CDT
In force: 30 min
Issued by: the Storm Prediction Center

All 53 counties

Clark County, AR, Dallas County, AR, Garland County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Little River County, AR, Miller County, AR, Montgomery County, AR, Nevada County, AR, Pike County, AR, Polk County, AR, Scott County, AR, Sevier County, AR, Yell County, AR, Bryan County, OK, Choctaw County, OK, McCurtain County, OK, Pushmataha County, OK, Bosque County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Morris County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Somervell County, TX, Tarrant County, TX, Titus County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX, Young County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 137 km from the middle of the area, began a volume at 13:32 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 261May 1, 8:45 AM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 1.5 hours before the alert went out and 120 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 785 J/kg
Mixed-layer CIN: -211 J/kg
Mixed-layer LCL: 574 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 328 m²/s²
0-3 km storm-relative helicity: 568 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 35.3

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.

Issued	Product	Office	Counties	Lasted
Apr 30, 7:49 PM CDT	Mesoscale Discussion	SPC	Clay, Greene, Izard, Lawrence, Randolph, Sharp and 1 more	56 min
Apr 30, 8:47 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Conway, Faulkner, Garland, Grant and 12 more	58 min
Apr 30, 9:26 PM CDT	Mesoscale Discussion	SPC	Hempstead, Howard, Little River, Miller, Sevier	64 min
Apr 30, 11:39 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleburne, Conway, Craighead, Cross and 31 more	66 min
May 1, 1:16 AM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleburne, Conway, Craighead, Crittenden and 37 more	59 min
May 1, 3:50 AM CDT	Mesoscale Discussion	SPC	Lee, Monroe, Phillips	2 hr
May 1, 8:45 AM CDT	Severe Thunderstorm Watch	SPC	Clark, Columbia, Dallas, Garland, Hempstead, Hot Spring and 10 more	6 hr
May 1, 12:12 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 34 more	93 min
May 1, 12:47 PM CDT	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 27 more	8 hr
May 1, 3:18 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more	87 min
May 1, 5:42 PM CDT	Mesoscale Discussion	SPC	Clark, Dallas, Garland, Grant, Hempstead, Hot Spring and 14 more	3 hr
May 1, 5:43 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more	92 min
May 1, 1:40 AM CDT	Severe Thunderstorm Watch	SPC	Bryan, Love, Marshall	7 hr
May 1, 3:19 AM CDT	Mesoscale Discussion	SPC	Caddo, Carter, Comanche, Cotton, Garvin, Grady and 10 more	86 min
May 1, 4:45 AM CDT	Tornado Watch	SPC	McCurtain	4 hr
May 1, 7:29 AM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Carter, Choctaw, Coal, Comanche and 11 more	91 min
May 1, 1:14 AM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coleman, Collin, Comanche and 28 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2011 Mesoscale Discussions in Arkansas, 2011 Mesoscale Discussions in Oklahoma, 2011 Every 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.