Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 991

May 30, 20124 states

The Storm Prediction Center issued this mesoscale discussion at May 30, 2012, 11:21 PM CDT for 4 states. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
May 30, 2012, 11:21 PM CDT (04:21 UTC)
Expired
May 31, 2012, 1:15 AM CDT
In force
114 min
Issued by
the Storm Prediction Center
All 34 counties

Benton County, AR, Carroll County, AR, Madison County, AR, Washington County, AR, Cherokee County, KS, Barry County, MO, McDonald County, MO, Newton County, MO, Adair County, OK, Caddo County, OK, Canadian County, OK, Cherokee County, OK, Cleveland County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Grady County, OK, Lincoln County, OK, Mayes County, OK, McClain County, OK, McIntosh County, OK, Muskogee County, OK, Nowata County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Ottawa County, OK, Payne County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Tulsa radar (KINX), 60 km from the middle of the area, began a volume at 04:23 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

Norman, OK (KOUN), launched 00:00Z, 4.4 hours before the alert went out and 137 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, Norman, OK at 00:00Z on 2012-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1232 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, Norman, OK at 00:00Z on 2012-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 64 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
1232 J/kg
Mixed-layer CIN
-138 J/kg
Mixed-layer LCL
1687 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
64 m²/s²
0-3 km storm-relative helicity
164 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

349 
ACUS11 KWNS 310422
SWOMCD
SPC MCD 310421
ARZ000-MOZ000-OKZ000-KSZ000-310615-

MESOSCALE DISCUSSION 0991
NWS STORM PREDICTION CENTER NORMAN OK
1121 PM CDT WED MAY 30 2012

AREAS AFFECTED...OK...SERN KS...SWRN MO...NWRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 325...326...

VALID 310421Z - 310615Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
325...326...CONTINUES.

SUMMARY...A THREAT OF DAMAGING WIND GUSTS AND MARGINAL HAIL REMAIN
POSSIBLE AREA-WIDE...BUT THE THREAT MAY BE DECREASING OVER WRN
AREAS.

DISCUSSION...CURIOUSLY...THE RAP BASED OBJECTIVE ANALYSIS HAS
STUBBORNLY KEPT A VERY STRONG AXIS OF INSTABILITY OVER THE ERN TX
PANHANDLE INTO WRN OK THIS EVENING...DESPITE HOURS OF COOL AND DRY
SURFACE OBSERVATIONS FROM EARLIER OUTFLOW. MODIFYING THE CDS
SOUNDING FOR CURRENT CONDITIONS YIELDS PERHAPS 100 J/KG
SBCAPE...WHILE THE RAP MODEL SUGGESTS THERE SHOULD BE 2500 J/KG.

DEWPOINTS ARE MIXING INTO THE UPPER 40S AND LOWER 50S OVER MUCH OF
THIS AREA. THESE OBSERVATIONS BLEND WELL WITH CURRENT RADAR TRENDS
WHICH SHOW WEAKENING OF THE CONVECTION OVER NWRN OK.

SURFACE ANALYSIS AND THE 00Z NORMAN SOUNDING DO INDICATE THERE IS
MORE SUBSTANTIAL MOISTURE PRESENT OVER CNTRL AND ERN OK...WITH
DEWPOINTS IN THE LOWER TO MIDDLE 60S F. THIS WOULD APPEAR TO BE THE
MOST LIKELY AREA FOR SEVERE STORMS...AS THE OUTFLOW CONTINUES SWD
ACROSS THE STATE. NEW CELLS MAY DEVELOP...AND GUSTY WINDS AND
MARGINALLY SEVERE HAIL WILL BE POSSIBLE. THE HIGHEST THREAT AREA
OVERALL IS FROM CNTRL OK INTO NERN OK WHERE MORE VIGOROUS CELLS ARE
KEEPING UP WITH THE GUST FRONT. FOR AREAS FROM WRN OK INTO THE TX
PANHANDLE...THERE IS LITTLE ADDITIONAL ACTIVITY BEING GENERATED
BEHIND THE ADVANCING OUTFLOW...WHICH WILL LIKELY RESULT IN A GRADUAL
WEAKENING OF THESE WINDS IF NEW STORMS DO NOT DEVELOP.

..JEWELL/CORFIDI.. 05/31/2012

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

ATTN...WFO...SGF...TSA...ICT...OUN...

LAT...LON   35459482 34789736 34789820 34919847 35159861 35459815
            35969729 36369636 36909547 37219496 37149417 36719344
            36039348 35459482

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 31, 1:52 AM CDTMesoscale DiscussionSPCBenton, Crawford, Washington83 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 Oklahoma, 2012Mesoscale Discussions in Arkansas, 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.