Alert archive / Arkansas / Mesoscale Discussions in 2012

Mesoscale Discussion 992

May 31, 2012Benton County, Crawford County, Washington County, Arkansas; McDonald County, Missouri; Adair County, Haskell County, Sequoyah County, Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 31, 2012, 1:52 AM CDT for Benton County, Crawford County, Washington County, Arkansas; McDonald County, Missouri; Adair County, Haskell County, Sequoyah County, Oklahoma. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
May 31, 2012, 1:52 AM CDT (06:52 UTC)
Expired
May 31, 2012, 3:15 AM CDT
In force
83 min
Issued by
the Storm Prediction Center

Counties Benton County, AR, Crawford County, AR, Washington County, AR, McDonald County, MO, Adair County, OK, Haskell County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 66 km from the middle of the area, began a volume at 06:53 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

Springfield, MO (KSGF), launched 00:00Z, 6.9 hours before the alert went out and 150 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, Springfield, MO at 00:00Z on 2012-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 27 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, Springfield, MO at 00:00Z on 2012-05-31The 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
27 J/kg
Mixed-layer CIN
-316 J/kg
Mixed-layer LCL
2376 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
72 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.

292 
ACUS11 KWNS 310653
SWOMCD
SPC MCD 310652
ARZ000-MOZ000-OKZ000-310815-

MESOSCALE DISCUSSION 0992
NWS STORM PREDICTION CENTER NORMAN OK
0152 AM CDT THU MAY 31 2012

AREAS AFFECTED...PARTS OF NERN OK...SW MO AND NW AR

CONCERNING...SEVERE THUNDERSTORM WATCH 326...

VALID 310652Z - 310815Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 326
CONTINUES.

SUMMARY...THE RISK FOR POTENTIALLY DAMAGING WIND GUSTS CONTINUES
ACROSS PARTS OF NORTHWEST ARKANSAS AND ADJACENT NORTHEAST OKLAHOMA
AND SOUTHWEST MISSOURI THROUGH 08-09Z.  HOWEVER...THE NEED FOR AN
ADDITIONAL WW EAST OF WW 326 IS NOT CURRENTLY ANTICIPATED.

DISCUSSION...STRONGEST STORMS REMAINS FOCUSED WHERE LOW-LEVEL
CONVERGENCE IS STRONGEST ALONG THE LEADING EDGE OF AN EASTWARD
ADVANCING OUTFLOW NEAR/NORTH AND SOUTH OF A WEAK SURFACE LOW EAST OF
TULSA.  AREAS OF AT LEAST SHORT-LIVED INTENSIFICATION
CONTINUE...BUT...ON THE LARGER-SCALE...ACTIVITY APPEARS GENERALLY IN
A WEAKENING PROCESS.  THERE DOES APPEAR A LINGERING NARROW
PRE-FRONTAL LOW-LEVEL THERMAL RIDGE WHICH COULD PROVIDE SUFFICIENT
INSTABILITY TO SUSTAIN CONVECTION AT LEAST NEAR CURRENT LEVELS
ANOTHER COUPLE OF HOURS... THROUGH THE 08-09Z TIME FRAME...ACROSS
PARTS OF NORTHEASTERN OKLAHOMA/NORTHWEST ARKANSAS/AND SOUTHWEST
MISSOURI.  THIS INCLUDES AREAS NORTH OF FORT SMITH...INTO THE
FAYETTEVILLE AND ROGERS/BENTONVILLE AREA...WHERE IT APPEARS SIZABLE
SUB CLOUD TEMPERATURE-DEW POINT SPREADS COULD STILL CONTRIBUTE TO
THE RISK FOR A STRONG DOWNBURST AND POTENTIALLY DAMAGING SURFACE
GUSTS.

..KERR.. 05/31/2012

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

ATTN...WFO...SGF...TSA...

LAT...LON   35349546 35619528 36019484 36609459 36939413 36479368
            35829389 35319460 35139499 35149547 35349546

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 30, 7:32 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more8 hr
May 30, 11:21 PM CDTMesoscale DiscussionSPCBenton, Carroll, Madison, Washington114 min
May 31, 11:59 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Chicot, Crittenden, Cross, Desha and 6 more61 min
May 31, 12:59 PM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 4 more6 hr
May 31, 2:38 PM CDTMesoscale DiscussionSPCCrittenden, Phillips67 min
May 31, 1:56 PM CDTMesoscale DiscussionSPCDunklin, Mississippi, New Madrid, Pemiscot64 min
May 31, 2:34 PM CDTSevere Thunderstorm WatchSPCMississippi, New Madrid6 hr
May 30, 8:38 PM CDTMesoscale DiscussionSPCBeaver97 min

Nearby

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