Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 331

March 22, 201210 counties in Arkansas

The Storm Prediction Center issued this mesoscale discussion at Mar 22, 2012, 10:06 PM CDT for 10 counties in Arkansas. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Mar 22, 2012, 10:06 PM CDT (03:06 UTC)
Expired: Mar 22, 2012, 11:30 PM CDT
In force: 84 min
Issued by: the Storm Prediction Center

Counties Clark County, AR, Cleburne County, AR, Conway County, AR, Dallas County, AR, Faulkner County, AR, Grant County, AR, Hot Spring County, AR, Perry County, AR, Pulaski County, AR, Saline County, AR

The radar

The Little Rock radar (KLZK), 34 km from the middle of the area, began a volume at 03:09 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 00:00Z, 3.1 hours before the alert went out and 243 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 202 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 1128 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

626 
ACUS11 KWNS 230306
SWOMCD
SPC MCD 230306 
ARZ000-230430-

MESOSCALE DISCUSSION 0331
NWS STORM PREDICTION CENTER NORMAN OK
1006 PM CDT THU MAR 22 2012

AREAS AFFECTED...PARTS OF CENTRAL AR

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 230306Z - 230430Z

LOCALIZED STRONG WIND GUSTS ARE POSSIBLE WITH THE STRONGER TSTM
ACTIVITY TRACKING NEWD ACROSS WRN INTO CENTRAL AR LATE THIS EVENING.
 THE LIKELIHOOD THAT THESE STORMS ARE ELEVATED WILL LIMIT THE SEVERE
WEATHER THREAT...AND PRECLUDES THE NEED FOR A WW.

SINCE 0130Z...REGIONAL RADAR IMAGERY INDICATED AN INCREASE IN TSTM
DEVELOPMENT ACROSS WRN AR...WITH A BROKEN LINE OF STORMS EXTENDING
FROM CLARK TO SALINE TO WRN SEARCY COUNTIES.  TRENDS IN WATER VAPOR
IMAGERY SHOWED A MIDLEVEL SHORTWAVE TROUGH MOVING FROM ERN OK/FAR
NERN TX INTO AR LATE THIS EVENING...WITH THIS TROUGH EMBEDDED WITHIN
A LARGE CLOSED LOW CENTERED OVER OK/ERN KS.  ASCENT ATTENDANT TO
THIS FEATURE COMBINED WITH THE EXIT REGIONS OF 75 KT MID AND UPPER
LEVEL JETS ROUNDING THE BASE OF THE CLOSED LOW INTO AR AT THIS
TIME...AND LOW LEVEL CONVERGENCE EXTENDING FROM NERN TX INTO WRN AR
ARE SUPPORTING THIS ACTIVITY.  EFFECTIVE BULK SHEAR EXCEEDING 50 KT
IS SUFFICIENT FOR STORM ORGANIZATION...BUT WEAKENING INSTABILITY
/MUCAPE LESS THAN 500 J PER KG/ AND DECOUPLING BOUNDARY LAYER ARE
PRECLUDING THE POTENTIAL FOR STRONG WIND GUSTS. 

SHORT TERM MODELS SUGGEST THE ONGOING STORMS WILL PERSIST WITH
SIMILAR INTENSITIES THROUGH 05Z..AND THEN WEAKEN.  THE
AFOREMENTIONED THERMODYNAMICS AND KINEMATICS CONFIRM THIS MODEL
OUTPUT...AND THUS PRECLUDE THE NEED FOR A WATCH.

..PETERS.. 03/23/2012

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

ATTN...WFO...LZK...SHV...

LAT...LON   33819345 34509308 35279284 35549259 35679233 35999154
            35879154 34739207 34269226 33709291 33589320 33819345

Nearby

Mesoscale Discussions in Arkansas, 2012 Every 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.