Alert archive / Missouri / Mesoscale Discussions in 2012

Mesoscale Discussion 1920

September 7, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2012, 6:06 PM CDT for 4 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Sep 7, 2012, 6:06 PM CDT (23:06 UTC)
Expired
Sep 7, 2012, 7:30 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 44 counties

Baxter County, AR, Boone County, AR, Carroll County, AR, Crawford County, AR, Franklin County, AR, Fulton County, AR, Izard County, AR, Johnson County, AR, Logan County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Searcy County, AR, Sebastian County, AR, Washington County, AR, Bond County, IL, Clinton County, IL, Madison County, IL, Monroe County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Carter County, MO, Dent County, MO, Douglas County, MO, Howell County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Oregon County, MO, Ozark County, MO, Perry County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Shannon County, MO, Taney County, MO, Texas County, MO, Washington County, MO, Wayne County, MO, Haskell County, OK, Latimer County, OK, LeFlore County, OK, Sequoyah County, OK

The radar

The Springfield radar (KSGF), 116 km from the middle of the area, began a volume at 23:09 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 12:00Z, 11.1 hours before the alert went out and 145 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 2012-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1095 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 12:00Z on 2012-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 256 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
1095 J/kg
Mixed-layer CIN
-182 J/kg
Mixed-layer LCL
1368 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
256 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.9

Open this sounding in Storm Lab

The text

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

867 
ACUS11 KWNS 072307
SWOMCD
SPC MCD 072306
ILZ000-MOZ000-ARZ000-OKZ000-080030-

MESOSCALE DISCUSSION 1920
NWS STORM PREDICTION CENTER NORMAN OK
0606 PM CDT FRI SEP 07 2012

AREAS AFFECTED...SOUTHERN/EASTERN MO AND SOUTHWEST IL/NORTHWEST
AR/EASTERN OK

CONCERNING...SEVERE THUNDERSTORM WATCH 630...

VALID 072306Z - 080030Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 630
CONTINUES.

SUMMARY...SEVERE TSTM WATCH 630 CONTINUES UNTIL 03Z...WITH DAMAGING
WINDS/SEVERE HAIL REMAIN POSSIBLE THROUGH EARLY/MID EVENING ACROSS
MUCH OF SOUTHERN/EASTERN MO INTO SOUTHWEST IL...IN ADDITION TO
NORTHWEST AR/EASTERN OK.

DISCUSSION...ALONG AND AHEAD OF A COLD FRONT /AND A SURFACE LOW NEAR
OR SOUTH OF ST LOUIS/...A COMPLEX CONVECTIVE MODE CONTINUES TO
EVOLVE ESPECIALLY ACROSS SOUTHERN/EASTERN MO INTO SOUTHWEST IL AMID
INCREASINGLY NUMEROUS TSTMS. HERE...SOMEWHAT MORE ISOLATED/MORE
ROBUST UPDRAFTS CONTINUE TO DEVELOP ACROSS SOUTHEAST MO/SOUTHWEST IL
AS OF 2245Z. THIS DEVELOPMENT IS SOME 50-75 MILES AHEAD OF A
MORE-ORGANIZED/QUASI-LINEAR CONVECTIVE MODE ADVANCING SOUTHEASTWARD
AT AROUND 45 KT ACROSS SOUTHWEST MO/NORTHWEST AR INTO EASTERN
OK...WITH THIS QLCS FEATURING A NORTHEAST-PERIPHERAL VORTEX MOVING
INTO SOUTH-CENTRAL MO IN VICINITY OF LACLEDE/WRIGHT/TEXAS COUNTIES
AS OF 2245Z. RECENTLY MEASURED SEVERE/NEAR-SEVERE GUSTS INCLUDE 49
KT AT FAYETTEVILLE AR /2225Z/.

OVER THE NEXT HOUR OR TWO /THROUGH 00Z-01Z/...SEVERE HAIL/DAMAGING
WINDS WILL REMAIN POSSIBLE WITH ONGOING STORMS ACROSS FAR SOUTHEAST
MO/SOUTHWEST IL. DAMAGING WINDS WILL BE THE PRIMARY CONCERN ACROSS
THE REMAINDER OF SOUTHERN MO INTO NORTHWEST AR/EASTERN OK...ALTHOUGH
A BRIEF TORNADO MAY BE POSSIBLE ACROSS SOUTH-CENTRAL MO WITH THE
AFOREMENTIONED VORTEX. ULTIMATELY...THE SQUALL LINE SHOULD CONTINUE
TO GRADUALLY OVERTAKE THE PRE-QLCS TSTMS WITH ADDITIONAL UPSCALE
GROWTH AND LIKELY SOUTHEASTWARD-PERSISTENCE OF A DAMAGING WIND
THREAT INTO RECENTLY ISSUED SEVERE TSTM WATCH 632.

..GUYER.. 09/07/2012

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

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA...

LAT...LON   35039581 36069443 37219247 38239083 39018965 38988904
            38128941 37129032 36279146 34709468 35039581

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 7, 2:35 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more6 hr
Sep 7, 3:09 PM CDTMesoscale DiscussionSPCBaxter, Cleburne, Conway, Craighead, Cross, Faulkner and 28 more66 min
Sep 7, 3:44 PM CDTMesoscale DiscussionSPCClay, Greene, Mississippi2 hr
Sep 7, 5:15 PM CDTSevere Thunderstorm WatchSPCArkansas, Baxter, Boone, Clay, Cleburne, Conway and 40 more7 hr
Sep 7, 10:09 AM CDTMesoscale DiscussionSPCClark, Coles, Crawford, Cumberland, Douglas, Edgar and 5 more2 hr
Sep 7, 3:22 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Clark, Coles, Crawford and 23 more53 min
Sep 7, 3:41 PM CDTSevere Thunderstorm WatchSPCChristian, Clark, Clay, Coles, Crawford, Cumberland and 8 more6 hr
Sep 7, 1:41 PM CDTMesoscale DiscussionSPCAudrain, Barry, Barton, Bates, Benton, Boone and 47 more94 min
Sep 6, 7:17 PM CDTMesoscale DiscussionSPCBeaver, Harper88 min
Sep 7, 2:44 PM CDTMesoscale DiscussionSPCBeckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 24 more2 hr

Nearby

Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Illinois, 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.