Alert archive / Arkansas / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 91, NWS Little Rock, AR

April 21, 20174 counties in Arkansas

NWS Little Rock, AR issued this severe thunderstorm warning at Apr 21, 2017, 7:57 AM CDT for 4 counties in Arkansas. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 21, 2017, 7:57 AM CDT (12:57 UTC)
Expired
Apr 21, 2017, 8:45 AM CDT
In force
48 min
Issued by
NWS Little Rock, AR
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Johnson County, AR, Logan County, AR, Pope County, AR, Yell County, AR

The radar

The Western Arkansas radar (KSRX), 87 km from the middle of the area, began a volume at 12:56 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

Springfield, MO (KSGF), launched 12:00Z, 1.0 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-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 2017-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2017-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -171 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
637 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-171 m²/s²
0-3 km storm-relative helicity
-150 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Little Rock, AR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 7:29 AM CDTSpecial Weather StatementLZKJohnson46 min
Apr 21, 9:58 AM CDTRiver Flood WarningLZKIndependence, Jackson, Lawrence49 days
Apr 21, 1:13 PM CDTSpecial Weather StatementLZKLogan, Scott, Yell47 min
Apr 21, 1:24 PM CDTSevere Thunderstorm WarningLZKLogan, Scott, Yell51 min
Apr 21, 1:54 PM CDTSpecial Weather StatementLZKJohnson51 min
Apr 21, 2:14 PM CDTSpecial Weather StatementLZKConway, Faulkner, Pope, Van Buren46 min
Apr 21, 2:20 PM CDTAreal Flood WarningLZKBaxter, Fulton115 min
Apr 21, 2:26 PM CDTSpecial Weather StatementLZKSearcy, Stone49 min
Apr 21, 2:47 PM CDTAreal Flood AdvisoryLZKBoone, Marion, Newton, Searcy3 hr

Nearby

Severe Thunderstorm Warnings in Arkansas, 2017Every severe thunderstorm warning in 2017

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.