Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 85

February 1, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2012, 1:22 PM CST for 4 states. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Feb 1, 2012, 1:22 PM CST (19:22 UTC)
Expired
Feb 1, 2012, 3:15 PM CST
In force
113 min
Issued by
the Storm Prediction Center
All 58 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Conway County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sevier County, AR, Union County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, Union Parish, LA, Webster Parish, LA, LeFlore County, OK, McCurtain County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Red River County, TX, Titus County, TX, Upshur County, TX

The radar

The Little Rock radar (KLZK), 127 km from the middle of the area, began a volume at 19:25 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

Shreveport, LA (KSHV), launched 12:00Z, 7.4 hours before the alert went out and 171 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 2012-02-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 302 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 2012-02-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 86 square meters per square second.1939587897Sfc1 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
302 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
588 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

606 
ACUS11 KWNS 011923
SWOMCD
SPC MCD 011922
ARZ000-MSZ000-LAZ000-TXZ000-OKZ000-012115-

MESOSCALE DISCUSSION 0085
NWS STORM PREDICTION CENTER NORMAN OK
0122 PM CST WED FEB 01 2012

AREAS AFFECTED...FROM CNTRL AR SWWD INTO THE ARKLATEX

CONCERNING...SEVERE THUNDERSTORM WATCH 20...

VALID 011922Z - 012115Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 20
CONTINUES.

SEVERE HAIL THREAT IS INCREASING OVER THE REGION...WITH A DECIDED
UPSWING IN THE INTENSITY OF A LEADING STORM OVER W CNTRL AR. RADAR
INDICATES SEVERE HAIL IS LIKELY WITH THIS STORM...AND GIVEN
PARAMETERS IN PLACE INCLUDING HODOGRAPH LENGTH AS WELL AS STORM
STRUCTURE...THIS STORM MAY BE PRODUCING LARGE AMOUNTS OF HAIL IN
ADDITION TO LARGE SIZES. AT THE CURRENT SPEED...THESE HAIL STORMS
WILL AFFECT THE LITTLE ROCK AREA BETWEEN 230-300 PM LOCAL TIME.

OTHER STORMS WERE STRENGTHENING OVER SWRN AR...WITH OTHER CELLS NOW
DEVELOPING OVER NERN TX. VERY LARGE HAIL WILL CONTINUE TO BE THE
PRIMARY SEVERE THREAT...BUT DAMAGING WINDS MAY ALSO OCCUR. WEAK LOW
LEVEL SHEAR WILL CONTINUE TO MINIMIZE THE RISK OF TORNADOES.

..JEWELL.. 02/01/2012

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

ATTN...WFO...MEG...JAN...LZK...SHV...TSA...

LAT...LON   33069110 32029512 34819514 35819110 33069110

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 1, 10:18 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 43 more117 min
Feb 1, 12:37 PM CSTSevere Thunderstorm WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 34 more5 hr
Feb 1, 2:58 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 25 more2 hr
Feb 1, 3:45 PM CSTSevere Thunderstorm WatchSPCAshley, Chicot, Crittenden, Cross, Lee, Phillips and 1 more3 hr
Feb 1, 1:06 AM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Calcasieu, Cameron, East Feliciana and 5 more114 min
Feb 1, 1:36 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 12 more84 min
Feb 1, 5:18 PM CSTMesoscale DiscussionSPCAscension, Livingston, Orleans, Saint Charles, Saint James, Saint John the Baptist and 2 more87 min

Nearby

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