Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 1853

August 4, 201132 counties in Arkansas; 16 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2011, 1:04 PM CDT for 32 counties in Arkansas; 16 counties in Oklahoma. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Aug 4, 2011, 1:04 PM CDT (18:04 UTC)
Expired
Aug 4, 2011, 2:00 PM CDT
In force
56 min
Issued by
the Storm Prediction Center
All 48 counties

Arkansas County, AR, Clark County, AR, Cleveland County, AR, Conway County, AR, Dallas County, AR, Faulkner County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lee 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, Sevier County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Atoka County, OK, Coal County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, McIntosh County, OK, Okfuskee County, OK, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Pushmataha County, OK, Seminole County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 81 km from the middle of the area, began a volume at 18:06 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, 6.1 hours before the alert went out and 245 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 2011-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1796 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 2011-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.1939Sfc1 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
1796 J/kg
Mixed-layer CIN
-191 J/kg
Mixed-layer LCL
1514 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
113 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.4

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
Aug 4, 2:10 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 9 more80 min
Aug 4, 8:06 AM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Independence and 8 more4 hr

Nearby

Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Oklahoma, 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.