Alert archive / Oklahoma / Mesoscale Discussions in 2011

Mesoscale Discussion 2188

September 18, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2011, 2:45 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 18, 2011, 2:45 PM CDT (19:45 UTC)
Expired
Sep 18, 2011, 4:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 29 counties

Benton County, AR, Crawford County, AR, Sebastian County, AR, Washington County, AR, Cherokee County, KS, Labette County, KS, Jasper County, MO, McDonald County, MO, Newton County, MO, Adair County, OK, Atoka County, OK, Cherokee County, OK, Craig County, OK, Delaware County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, Mayes County, OK, McIntosh County, OK, Muskogee County, OK, Nowata County, OK, Okmulgee County, OK, Ottawa County, OK, Pittsburg County, OK, Pushmataha County, OK, Rogers County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Tulsa radar (KINX), 51 km from the middle of the area, began a volume at 19:46 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

Springfield, MO (KSGF), launched 12:00Z, 7.8 hours before the alert went out and 178 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 12:00Z on 2011-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2011-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 228 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1001 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
350 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.

294 
ACUS11 KWNS 181946
SWOMCD
SPC MCD 181945
ARZ000-MOZ000-OKZ000-KSZ000-182145-

MESOSCALE DISCUSSION 2188
NWS STORM PREDICTION CENTER NORMAN OK
0245 PM CDT SUN SEP 18 2011

AREAS AFFECTED...ERN OK...PARTS OF SE KS/SW MO/WRN AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 181945Z - 182145Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT THAT
COULD REQUIRE A WATCH...POSSIBLY WITHIN THE NEXT HOUR OR TWO.

WITHIN LARGER SCALE UPPER TROUGHING LIFTING OUT OF THE CENTRAL/
SOUTHERN HIGH PLAINS...AN AREA OF STRONGER FORCING FOR ASCENT
ASSOCIATED WITH AN EMBEDDED LOBE OF CYCLONIC VORTICITY IS NOW
SPREADING EAST OF THE TEXAS/OKLAHOMA PANHANDLE REGION TOWARD THE
OZARKS.  THIS MAY CONTRIBUTE TO INCREASING STORM DEVELOPMENT BY THE
21-23Z TIME FRAME...ACROSS PARTS OF EASTERN OKLAHOMA INTO ADJACENT
SOUTHEAST KANSAS/SOUTHWEST MISSOURI AND WESTERN ARKANSAS...WHERE
DESTABILIZATION IS ONGOING...AND WARM ADVECTION IS ENHANCED ON THE
NOSE OF AN AXIS OF STRONGER SURFACE HEATING EXTENDING NORTHEASTWARD
OUT OF CENTRAL TEXAS.  VERTICAL SHEAR IS STILL FAIRLY MODEST...BUT
MODEL GUIDANCE IS SUGGESTIVE THAT SOME STRENGTHENING OF MID-LEVEL
FLOW COULD OCCUR LATE THIS AFTERNOON...WHICH MAY BECOME SUPPORTIVE
OF ORGANIZED CONVECTIVE DEVELOPMENT...PERHAPS AN ISOLATED SUPERCELL
OR TWO.

..KERR.. 09/18/2011

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

ATTN...WFO...LZK...SGF...SHV...TSA...ICT...OUN...

LAT...LON   35559633 36519598 37269555 37289425 36479369 35079405
            34089488 34409608 35559633

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 3:30 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more8 hr
Sep 18, 5:41 PM CDTSevere Thunderstorm WatchSPCBoone, Clark, Columbia, Conway, Garland, Hempstead and 19 more7 hr
Sep 18, 6:48 PM CDTMesoscale DiscussionSPCBenton, Carroll, Conway, Crawford, Garland, Howard and 11 more57 min
Sep 17, 10:17 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Carter, Cherokee, Cleveland, Coal and 28 more88 min
Sep 18, 3:59 PM CDTMesoscale DiscussionSPCLove31 min

Nearby

Mesoscale Discussions in Oklahoma, 2011Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Missouri, 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.