Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 420

April 2, 201229 counties in Arkansas; 10 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 5:58 PM CDT for 29 counties in Arkansas; 10 counties in Oklahoma. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued
Apr 2, 2012, 5:58 PM CDT (22:58 UTC)
Expired
Apr 2, 2012, 7:00 PM CDT
In force
62 min
Issued by
the Storm Prediction Center
All 39 counties

Arkansas County, AR, Clark County, AR, Cleveland County, AR, Conway County, AR, Dallas County, AR, Desha County, AR, Faulkner County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Johnson County, AR, Lincoln County, AR, Logan County, AR, Lonoke County, AR, Monroe County, AR, Montgomery County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sebastian County, AR, Yell County, AR, Atoka County, OK, Coal County, OK, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, McIntosh County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 95 km from the middle of the area, began a volume at 23:01 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 12:00Z, 11.0 hours before the alert went out and 232 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 12:00Z on 2012-04-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1679 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 12:00Z on 2012-04-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -91 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
1679 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
558 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-91 m²/s²
0-3 km storm-relative helicity
4 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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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 2, 12:15 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Clark, Cleveland and 17 more90 min
Apr 2, 12:41 PM CDTSevere Thunderstorm WatchSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 11 more6 hr
Apr 2, 12:50 PM CDTSevere Thunderstorm WatchSPCAshley, Chicot7 hr
Apr 2, 3:18 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Clark, Cleveland, Columbia and 28 more117 min
Apr 2, 3:23 PM CDTMesoscale DiscussionSPCAshley, Chicot2 hr
Apr 2, 3:49 PM CDTSevere Thunderstorm WatchSPCArkansas, Conway, Crawford, Desha, Faulkner, Franklin and 19 more4 hr
Apr 2, 3:00 PM CDTMesoscale DiscussionSPCAlfalfa, Beaver, Beckham, Blaine, Caddo, Canadian and 16 more2 hr
Apr 2, 3:37 PM CDTSevere Thunderstorm WatchSPCAlfalfa, Beaver, Beckham, Blaine, Caddo, Comanche and 16 more7 hr

Nearby

Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Oklahoma, 2012Every 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.