Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 631

April 30, 201227 counties in Arkansas; 4 counties in Mississippi; Shelby County, Tipton County, Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2012, 1:55 PM CDT for 27 counties in Arkansas; 4 counties in Mississippi; Shelby County, Tipton County, Tennessee. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 30, 2012, 1:55 PM CDT (18:55 UTC)
Expired: Apr 30, 2012, 4:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 33 counties

Arkansas County, AR, Clark County, AR, Cleveland County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Nevada County, AR, Ouachita County, AR, Phillips County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, Woodruff County, AR, Coahoma County, MS, DeSoto County, MS, Tate County, MS, Tunica County, MS, Shelby County, TN, Tipton County, TN

The radar

The Little Rock radar (KLZK), 58 km from the middle of the area, began a volume at 18:57 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

Little Rock, AR (KLZK), launched 12:00Z, 6.9 hours before the alert went out and 180 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: 1195 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 686 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

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Nearby

Mesoscale Discussions in Arkansas, 2012 Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Tennessee, 2012 Every mesoscale discussion 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.