Alert archive / Arkansas / Mesoscale Discussions in 2013

Mesoscale Discussion 735

May 20, 201322 counties in Arkansas; 14 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 20, 2013, 6:53 PM CDT for 22 counties in Arkansas; 14 counties in Missouri. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
May 20, 2013, 6:53 PM CDT (23:53 UTC)
Expired
May 20, 2013, 8:00 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 36 counties

Baxter County, AR, Boone County, AR, Cleburne County, AR, Conway County, AR, Franklin County, AR, Fulton County, AR, Izard County, AR, Johnson County, AR, Logan County, AR, Marion County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Polk County, AR, Pope County, AR, Randolph County, AR, Scott County, AR, Searcy County, AR, Sharp County, AR, Stone County, AR, Van Buren County, AR, Yell County, AR, Carter County, MO, Dent County, MO, Douglas County, MO, Howell County, MO, Iron County, MO, Madison County, MO, Oregon County, MO, Ozark County, MO, Reynolds County, MO, Ripley County, MO, Shannon County, MO, Taney County, MO, Texas County, MO, Wayne County, MO

The radar

The Little Rock radar (KLZK), 137 km from the middle of the area, began a volume at 23:50 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, 11.9 hours before the alert went out and 148 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 2013-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 2013-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
4 J/kg
Mixed-layer CIN
-445 J/kg
Mixed-layer LCL
1092 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
208 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.4

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
May 19, 10:44 PM CDTTornado WatchSPCBenton, Crawford, Washington5 hr
May 20, 12:26 PM CDTMesoscale DiscussionSPCBenton, Washington2 hr
May 20, 1:10 PM CDTTornado WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more9 hr
May 19, 7:13 PM CDTMesoscale DiscussionSPCClark62 min
May 19, 7:55 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Clay, Clinton, DeKalb and 4 more65 min
May 19, 8:10 PM CDTTornado WatchSPCClark, Scotland6 hr
May 19, 10:16 PM CDTMesoscale DiscussionSPCAdair, Audrain, Barry, Barton, Bates, Benton and 52 more59 min
May 19, 11:49 PM CDTMesoscale DiscussionSPCBarry, Barton, Camden, Cedar, Christian, Dade and 17 more56 min
May 20, 8:46 AM CDTMesoscale DiscussionSPCBates, Benton, Cass, Henry, Jackson, Johnson and 4 more59 min
May 20, 12:46 PM CDTTornado WatchSPCBarry, Barton, Bates, Benton, Boone, Callaway and 41 more8 hr
May 20, 3:27 PM CDTMesoscale DiscussionSPCAudrain, Lincoln, Marion, Monroe, Montgomery, Pike and 2 more63 min
May 20, 5:07 PM CDTMesoscale DiscussionSPCAudrain, Crawford, Franklin, Gasconade, Lincoln, Marion and 8 more23 min
May 20, 5:24 PM CDTTornado WatchSPCAudrain, Boone, Callaway, Clark, Cole, Crawford and 20 more7 hr
May 20, 5:38 PM CDTMesoscale DiscussionSPCAndrew, DeKalb, Gentry, Harrison, Worth67 min

Nearby

Mesoscale Discussions in Arkansas, 2013Mesoscale Discussions in Missouri, 2013Every mesoscale discussion in 2013

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.