Alert archive / Missouri / Mesoscale Discussions in 2012

Mesoscale Discussion 1913

September 7, 201253 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2012, 1:41 PM CDT for 53 counties in Missouri. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Sep 7, 2012, 1:41 PM CDT (18:41 UTC)
Expired
Sep 7, 2012, 3:15 PM CDT
In force
94 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 53 counties

Audrain County, MO, Barry County, MO, Barton County, MO, Bates County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Cass County, MO, Cedar County, MO, Christian County, MO, Cole County, MO, Cooper County, MO, Crawford County, MO, Dade County, MO, Dallas County, MO, Dent County, MO, Douglas County, MO, Franklin County, MO, Gasconade County, MO, Greene County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Howell County, MO, Jasper County, MO, Johnson County, MO, Laclede County, MO, Lafayette County, MO, Lawrence County, MO, Maries County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Ozark County, MO, Pettis County, MO, Phelps County, MO, Polk County, MO, Pulaski County, MO, Randolph County, MO, Saline County, MO, Shannon County, MO, St. Clair County, MO, Stone County, MO, Taney County, MO, Texas County, MO, Vernon County, MO, Warren County, MO, Webster County, MO, Wright County, MO

The radar

The Springfield radar (KSGF), 82 km from the middle of the area, began a volume at 18:44 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, 6.7 hours before the alert went out and 133 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°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.

380 
ACUS11 KWNS 071841
SWOMCD
SPC MCD 071841 
MOZ000-072015-

MESOSCALE DISCUSSION 1913
NWS STORM PREDICTION CENTER NORMAN OK
0141 PM CDT FRI SEP 07 2012

AREAS AFFECTED...PORTIONS OF MO

CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY 

VALID 071841Z - 072015Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...A SEVERE THUNDERSTORM WATCH WILL LIKELY BE REQUIRED BY
ABOUT 2000Z AS THE THREAT FOR SVR WIND/HAIL INCREASES THIS
AFTERNOON.

DISCUSSION...A CLUSTER OF ELEVATED CONVECTION IN KS IN ASSOCIATION
WITH A MID-LEVEL IMPULSE CONTINUES TO BE STEERED EWD ATOP A
WWD/NWD-GRADUALLY-SLOPING FRONT THAT INTERSECTS THE SFC FROM N-CNTRL
TO SWRN MO INTO NERN OK. AS THIS CONVECTION ENCOUNTERS INCREASING
INSTABILITY...ESPECIALLY NEAR AND EAST OF THE SFC FRONT WHERE
MODIFIED SOUNDINGS YIELD MLCAPE OF 1500-2500 J/KG...IT SHOULD
INTENSIFY WHILE BECOMING INCREASINGLY SFC-BASED. ALSO...A BAND OF
BOUNDARY-LAYER CUMULUS DEVELOPING INVOF A FRONTAL SEGMENT IN N-CNTRL
MO MAY EVOLVE INTO DEEPER CONVECTION WITH ADDITIONAL DIURNAL
HEATING/DESTABILIZATION. EFFECTIVE BULK SHEAR MAGNITUDES OF 20-35
KT...AND UNIDIRECTIONAL WIND PROFILES PER SPRINGFIELD VWP
DATA...SUGGEST ORGANIZED LINE SEGMENTS WITH DMGG WIND GUSTS WILL BE
OF CONCERN...WITH SVR HAIL ALSO POSSIBLE.

..COHEN/THOMPSON.. 09/07/2012

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

ATTN...WFO...LSX...SGF...EAX...

LAT...LON   36689399 37339454 38849447 39409305 39689171 38779098
            37689099 36749166 36529311 36689399

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 7, 2:35 PM CDTSevere Thunderstorm WatchSPCAudrain, Barry, Barton, Bates, Benton, Boone and 57 more6 hr
Sep 7, 3:44 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Dunklin, Mississippi, New Madrid and 5 more2 hr
Sep 7, 5:15 PM CDTSevere Thunderstorm WatchSPCBollinger, Butler, Cape Girardeau, Carter, Dunklin, Mississippi and 7 more7 hr
Sep 7, 6:06 PM CDTMesoscale DiscussionSPCCarter, Dent, Douglas, Howell, Iron, Jefferson and 12 more84 min

Nearby

Mesoscale 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.