Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 2350

November 21, 201113 counties in Arkansas; McCurtain County, Oklahoma; Bowie County, Red River County, Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 21, 2011, 8:16 PM CST for 13 counties in Arkansas; McCurtain County, Oklahoma; Bowie County, Red River County, Texas. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Nov 21, 2011, 8:16 PM CST (02:16 UTC)
Expired: Nov 21, 2011, 9:45 PM CST
In force: 89 min
Issued by: the Storm Prediction Center

Counties Clark County, AR, Dallas County, AR, Garland County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Little River County, AR, Montgomery County, AR, Nevada County, AR, Pike County, AR, Polk County, AR, Saline County, AR, Sevier County, AR, McCurtain County, OK, Bowie County, TX, Red River County, TX

The radar

The Western Arkansas radar (KSRX), 141 km from the middle of the area, began a volume at 02:19 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.

Tornado Watch 894Nov 21, 8:35 PM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 2.3 hours before the alert went out and 179 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: 485 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 1180 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 131 m²/s²
0-3 km storm-relative helicity: 246 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.0

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
Nov 21, 8:36 PM CST	Tornado Watch	SPC	Arkansas, Clark, Cleveland, Dallas, Garland, Grant and 17 more	5 hr
Nov 21, 10:45 PM CST	Mesoscale Discussion	SPC	Clark, Garland, Hempstead, Hot Spring, Howard, Little River and 6 more	90 min
Nov 22, 1:46 AM CST	Mesoscale Discussion	SPC	Arkansas, Clark, Cleveland, Dallas, Garland, Grant and 17 more	59 min

Nearby

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