Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 400

March 31, 201213 counties in Arkansas; Dunklin County, Missouri

The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2012, 5:11 PM CDT for 13 counties in Arkansas; Dunklin County, Missouri. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Mar 31, 2012, 5:11 PM CDT (22:11 UTC)
Expired
Mar 31, 2012, 6:15 PM CDT
In force
64 min
Issued by
the Storm Prediction Center

Counties Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Independence County, AR, Jackson County, AR, Lawrence County, AR, Mississippi County, AR, Poinsett County, AR, Randolph County, AR, St. Francis County, AR, Woodruff County, AR, Dunklin County, MO

The radar

The Memphis radar (KNQA), 79 km from the middle of the area, began a volume at 22:11 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

Little Rock, AR (KLZK), launched 12:00Z, 10.2 hours before the alert went out and 107 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, Little Rock, AR at 12:00Z on 2012-03-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1894 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, Little Rock, AR at 12:00Z on 2012-03-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
1894 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
73 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.

311 
ACUS11 KWNS 312211
SWOMCD
SPC MCD 312211 
TNZ000-ARZ000-MSZ000-MOZ000-312315-

MESOSCALE DISCUSSION 0400
NWS STORM PREDICTION CENTER NORMAN OK
0511 PM CDT SAT MAR 31 2012

AREAS AFFECTED...NERN AR...MO BOOTHEEL...FAR WRN TN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 312211Z - 312315Z

AN ISOLATED THREAT FOR LARGE HAIL/DMGG WIND GUSTS WILL EXIST THROUGH
EARLY EVENING OVER NERN AR AND FAR WRN TN. COVERAGE IS EXPECTED TO
REMAIN TOO LOW TO WARRANT ISSUANCE OF A NEW WW. A WWD EXTENSION OF
WW 121 IS UNCERTAIN DUE TO SPARSE CONVECTIVE COVERAGE OVER WRN
TN/NERN AR.

VISIBLE SATELLITE/MOSAIC RADAR COMPOSITE LOOPS SHOW A RAPIDLY
DEVELOPING TSTM 20 WSW POF...MOVING SSEWD TOWARDS NERN AR. THIS IS
OCCURRING ALONG A WEAKLY CONFLUENT AND SLOW-MOVING WARM FRONT...WITH
ADDITIONAL ASCENT PERHAPS AIDED BY A SUBTLE UPPER WAVE TRANSLATING
SEWD WITHIN THE ERN PERIPHERY OF A BUILDING UPPER RIDGE OVER THE
GREAT PLAINS. GIVEN WEAK LARGE-SCALE ASCENT AND INCREASING INFLUENCE
OF THE CNTRL CONUS UPPER RIDGE...TSTM ACTIVITY IS EXPECTED TO REMAIN
RATHER ISOLATED. HOWEVER...BACKGROUND ENVIRONMENT REMAINS FAVORABLE
FOR LARGE HAIL AND ISOLATED DMGG WIND GUSTS...GIVEN MIDLEVEL LAPSE
RATES OF 7.5-8 C/KM AND EFFECTIVE SHEAR NEAR 30 KTS.

..ROGERS.. 03/31/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PAH...MEG...LZK...

LAT...LON   34799061 34909133 35749182 36399129 36649068 36359001
            35548992 34999002 34799061

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 31, 12:29 PM CDTMesoscale DiscussionSPCArkansas, Craighead, Crittenden, Cross, Desha, Lee and 7 more91 min

Nearby

Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Missouri, 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.