Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 234

March 8, 201222 counties in Arkansas; 4 counties in Oklahoma; 16 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 8, 2012, 10:19 AM CST for 22 counties in Arkansas; 4 counties in Oklahoma; 16 counties in Texas. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Mar 8, 2012, 10:19 AM CST (16:19 UTC)
Expired
Mar 8, 2012, 11:15 AM CST
In force
56 min
Issued by
the Storm Prediction Center
All 42 counties

Clark County, AR, Dallas County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sevier County, AR, Yell County, AR, Bryan County, OK, Choctaw County, OK, McCurtain County, OK, Pushmataha County, OK, Bowie County, TX, Camp County, TX, Collin County, TX, Delta County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Lamar County, TX, Morris County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Titus County, TX, Wood County, TX

The radar

The Western Arkansas radar (KSRX), 138 km from the middle of the area, began a volume at 16:19 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, 4.3 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, Shreveport, LA at 12:00Z on 2012-03-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1126 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 2012-03-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 214 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
1126 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
498 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
214 m²/s²
0-3 km storm-relative helicity
390 m²/s²
Significant tornado parameter
1.3
Supercell composite
6.9

Open this sounding in Storm Lab

The text

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

333 
ACUS11 KWNS 081619
SWOMCD
SPC MCD 081619 
ARZ000-TXZ000-OKZ000-081715-

MESOSCALE DISCUSSION 0234
NWS STORM PREDICTION CENTER NORMAN OK
1019 AM CST THU MAR 08 2012

AREAS AFFECTED...SERN OK...NERN TX...SWRN/CNTRL AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 081619Z - 081715Z

AN ISOLATED THREAT FOR DMGG WINDS AND LARGE HAIL WILL EXIST ACROSS
PORTIONS OF THE ARKLATEX AND FAR SERN OK. ALTHOUGH A WW IS NOT
CURRENTLY ANTICIPATED...CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED. 

16Z SFC ANALYSIS PLACES A COLD FRONT FROM 20 W RUE SWWD TO 30 W
GYI...DISPLAYING PRIMARILY ANAFRONTAL CHARACTERISTICS AS IT
PROGRESSES SEWD THROUGH THE ARKLATEX. RADAR REFLECTIVITY TRENDS SHOW
ISOLATED TSTMS DEVELOPING IN THE WARM SECTOR IMMEDIATELY AHEAD OF
THE COLD FRONT...PRIMARILY ALONG/NEAR THE RED RIVER VALLEY ATTM.
EXTENSIVE CLOUD COVER AND A MOIST/NEARLY SATURATED BOUNDARY LAYER IS
LIMITING INSTABILITY SOMEWHAT...ALTHOUGH 12Z SHV SOUNDING SAMPLED
STEEP LAPSE RATES WITHIN AN EML ABOVE 3 KM AGL. ADDITIONALLY...A
CAPPING INVERSION AT THE BASE OF THE EML HAS LIKELY WEAKENED WITH
TIME /PARTICULARLY WITH EWD EXTENT/. ALTHOUGH KINEMATIC PROFILES ARE
ONLY EXHIBITING WEAK VEERING WITH HEIGHT...MODERATE TO STRONG
LOWER-MID TROPOSPHERIC FLOW /SAMPLED AT 30-40 KTS IN 0.5-2 KM AGL
LAYER BY DQU PROFILER/ WILL SUPPORT A THREAT FOR ISOLATED DMGG WIND
GUSTS...AND PERHAPS AN ISOLATED TORNADO...WITH SFC-BASED CONVECTION
IN THE WARM SECTOR. ADDITIONALLY...A THREAT FOR LARGE HAIL WILL
EXIST ON BOTH SIDES OF THE COLD FRONT GIVEN STEEP MIDLEVEL LAPSE
RATES AND SUFFICIENT DEEP-LAYER SHEAR. SIGNIFICANT UNCERTAINTY OF
TSTM COVERAGE AHEAD OF THE COLD FRONT THROUGH THIS AFTERNOON STILL
EXISTS...AS WEAK MIDLEVEL RIDGING AND EXTENSIVE CLOUD COVER...ALONG
WITH THE ABSENCE OF STRONG FORCED ASCENT...COULD PRECLUDE A MORE
WIDESPREAD THREAT.

..ROGERS.. 03/08/2012

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

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

LAT...LON   35119192 34719178 33649269 33089444 32689503 32559577
            32889661 33689680 34239601 34789460 35189302 35329222
            35119192

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 8, 2:28 PM CSTMesoscale DiscussionSPCColumbia, Hempstead, Lafayette, Little River, Miller, Nevada62 min
Mar 7, 7:36 PM CSTMesoscale DiscussionSPCAlfalfa, Beckham, Blaine, Caddo, Canadian, Custer and 22 more84 min
Mar 8, 2:54 PM CSTMesoscale DiscussionSPCAtoka, Bryan, Carter, Choctaw, Coal, Cotton and 14 more66 min

Nearby

Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Oklahoma, 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.