Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 2307

November 8, 201112 counties in Arkansas

The Storm Prediction Center issued this mesoscale discussion at Nov 8, 2011, 6:43 PM CST for 12 counties in Arkansas. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Nov 8, 2011, 6:43 PM CST (00:43 UTC)
Expired: Nov 8, 2011, 7:45 PM CST
In force: 62 min
Issued by: the Storm Prediction Center

Counties Craighead County, AR, Crittenden County, AR, Cross County, AR, Independence County, AR, Jackson County, AR, Lonoke County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR

The radar

The Memphis radar (KNQA), 109 km from the middle of the area, began a volume at 00:46 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 878Nov 8, 7:05 PM CST

The nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 0.7 hours before the alert went out and 112 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: 682 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 351 m²/s²
0-3 km storm-relative helicity: 396 m²/s²
Significant tornado parameter: 1.9
Supercell composite: 7.2

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 8, 7:04 PM CST	Tornado Watch	SPC	Clay, Craighead, Crittenden, Cross, Faulkner, Greene and 13 more	2 hr
Nov 8, 9:21 PM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Chicot, Desha, Drew, Lincoln	84 min

Nearby

Mesoscale Discussions in Arkansas, 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.