Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 476

April 19, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2011, 6:24 PM CDT for 4 states. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2011, 6:24 PM CDT (23:24 UTC)
Expired
Apr 19, 2011, 7:30 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 45 counties

Arkansas County, AR, Clay County, AR, Cleveland County, AR, Craighead County, AR, Cross County, AR, Dallas County, AR, Grant County, AR, Greene County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Mississippi County, AR, Monroe County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Alexander County, IL, Franklin County, IL, Jackson County, IL, Johnson County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Williamson County, IL, Ballard County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO

The radar

The Memphis radar (KNQA), 106 km from the middle of the area, began a volume at 23:26 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.

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 11.4 hours before the alert went out and 287 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, Springfield, MO at 12:00Z on 2011-04-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2616 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, Springfield, MO at 12:00Z on 2011-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 583 square meters per square second.19395878Sfc1 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
2616 J/kg
Mixed-layer CIN
-284 J/kg
Mixed-layer LCL
820 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
583 m²/s²
0-3 km storm-relative helicity
584 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.6

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 19, 12:40 PM CDTMesoscale DiscussionSPCBenton95 min
Apr 19, 1:40 PM CDTMesoscale DiscussionSPCBenton, Crawford, Franklin, Johnson, Logan, Madison and 4 more65 min
Apr 19, 2:16 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Columbia, Conway and 29 more10 hr
Apr 19, 6:46 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 35 more9 hr
Apr 18, 11:41 PM CDTMesoscale DiscussionSPCCalhoun, Jersey94 min
Apr 19, 2:53 AM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 21 more67 min
Apr 19, 3:11 AM CDTSevere Thunderstorm WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 30 more7 hr
Apr 19, 5:52 AM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 34 more83 min
Apr 19, 8:29 AM CDTMesoscale DiscussionSPCChristian, Clark, Coles, Crawford, Cumberland, Douglas and 8 more61 min
Apr 19, 1:00 PM CDTTornado WatchSPCBond, Calhoun, Cass, Champaign, Christian, Clark and 36 more10 hr
Apr 19, 5:47 PM CDTMesoscale DiscussionSPCBond, Calhoun, Christian, Clark, Clay, Clinton and 25 more88 min

Nearby

Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Missouri, 2011Mesoscale Discussions in Illinois, 2011Every 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.