Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 682

May 1, 20114 states

The Storm Prediction Center issued this mesoscale discussion at May 1, 2011, 12:12 PM CDT for 4 states. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
May 1, 2011, 12:12 PM CDT (17:12 UTC)
Expired
May 1, 2011, 1:45 PM CDT
In force
93 min
Issued by
the Storm Prediction Center
All 85 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Drew County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Mississippi County, AR, Monroe County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Sevier County, AR, St. Francis County, AR, Union County, AR, White County, AR, Woodruff County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Lincoln Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Lauderdale County, TN, Tipton County, TN, Anderson County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Collin County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Fannin County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Marion County, TX, Morris County, TX, Navarro County, TX, Panola County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Rusk County, TX, Smith County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Little Rock radar (KLZK), 138 km from the middle of the area, began a volume at 17:11 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 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, 5.2 hours before the alert went out and 164 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 2011-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2344 joules per kilogram.LCLEL10008507005003002001001 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 2011-05-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 277 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
2344 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
499 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
277 m²/s²
0-3 km storm-relative helicity
370 m²/s²
Significant tornado parameter
4.9
Supercell composite
18.4

Open this sounding in Storm Lab

The text

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

541 
ACUS11 KWNS 011713
SWOMCD
SPC MCD 011712
TNZ000-MOZ000-ARZ000-LAZ000-TXZ000-OKZ000-011845-

MESOSCALE DISCUSSION 0682
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT SUN MAY 01 2011

AREAS AFFECTED...NERN TX...FAR SERN OK...SWRN/CNTRL AR...FAR WRN TN

CONCERNING...SEVERE THUNDERSTORM WATCH 261...

VALID 011712Z - 011845Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 261
CONTINUES.

LATEST SFC ANALYSIS DEPICTS A FRONTAL ZONE EXTENDING AS A COLD FRONT
FROM 15 E JBR TO 30 W PBF...AS A STATIONARY FRONT FARTHER SOUTHWEST
TO 25 NW TYR...AND AS A COLD FRONT SOUTHWEST INTO CNTRL TX. A MODEST
LLJ /SSWLY FLOW AROUND 30 KT PER FORT WORTH AND SHREVEPORT VWP DATA/
ATOP THE NWD-SLOPED FRONTAL SFC IS ALLOWING FOR CONVECTION TO
REGENERATE IN NERN SECTIONS OF WW 261...AND FARTHER NE INTO CNTRL AR
AND FAR WRN TN.

WHILE THE ACTIVITY APPEARS TO HAVE WANED ELSEWHERE TEMPORARILY...
VISIBLE SATELLITE IMAGERY DEPICTS BREAKS IN THE CLOUD COVERAGE NEAR
AND SOUTHEAST OF THE SFC BOUNDARY INTO THE WARM/UNSTABLE SECTOR.
HORIZONTAL CONVECTIVE ROLLS HAVE BEEN NOTED NEAR AND WEST OF THE
SHREVEPORT AREA. WITH CONTINUED DESTABILIZATION OWING TO
INSOLATION...AS WELL AS FRONTAL CONVERGENCE AND AMPLE LOW-LEVEL AND
DEEP-LAYER VERTICAL WIND SHEAR...AN INCREASING POTENTIAL FOR
SURFACE-BASED SEVERE THUNDERSTORMS /INCLUDING SUPERCELLS/ WITH THE
THREAT FOR TORNADOES WILL OCCUR NEAR THE FRONT AND WITHIN THE WARM
SECTOR. THUS...WW 261 WILL NEED TO BE REPLACED BY A TORNADO WATCH
WITHIN AN HOUR.

..COHEN.. 05/01/2011

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

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

LAT...LON   34929091 34509116 34129147 33469152 32709215 32109316
            31759445 31669604 32209683 32389782 32859778 33419719
            33709618 34159456 34729310 35319261 35969106 36129008
            35738933 35219001 34929091

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 7:49 PM CDTMesoscale DiscussionSPCClay, Greene, Izard, Lawrence, Randolph, Sharp and 1 more56 min
Apr 30, 8:47 PM CDTMesoscale DiscussionSPCArkansas, Clark, Conway, Faulkner, Garland, Grant and 12 more58 min
Apr 30, 9:26 PM CDTMesoscale DiscussionSPCHempstead, Howard, Little River, Miller, Sevier64 min
Apr 30, 11:39 PM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Conway, Craighead, Cross and 31 more66 min
May 1, 1:16 AM CDTMesoscale DiscussionSPCArkansas, Clark, Cleburne, Conway, Craighead, Crittenden and 37 more59 min
May 1, 3:50 AM CDTMesoscale DiscussionSPCLee, Monroe, Phillips2 hr
May 1, 8:30 AM CDTMesoscale DiscussionSPCClark, Dallas, Garland, Hempstead, Hot Spring, Howard and 9 more30 min
May 1, 8:45 AM CDTSevere Thunderstorm WatchSPCClark, Columbia, Dallas, Garland, Hempstead, Hot Spring and 10 more6 hr
May 1, 12:47 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 27 more8 hr
May 1, 3:18 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more87 min
May 1, 5:42 PM CDTMesoscale DiscussionSPCClark, Dallas, Garland, Grant, Hempstead, Hot Spring and 14 more3 hr
May 1, 5:43 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 37 more92 min
May 1, 1:14 AM CDTMesoscale DiscussionSPCBosque, Brown, Callahan, Coleman, Collin, Comanche and 28 more2 hr
May 1, 1:40 AM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 31 more7 hr
May 1, 3:19 AM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Collin, Comanche and 38 more86 min
May 1, 4:45 AM CDTTornado WatchSPCAnderson, Bowie, Camp, Cass, Cherokee, Delta and 21 more4 hr
May 1, 7:29 AM CDTMesoscale DiscussionSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 34 more91 min

Nearby

Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Louisiana, 2011Every mesoscale discussion in 2011

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.