Alert archive / Illinois / Mesoscale Discussions in 2012

Mesoscale Discussion 253

March 14, 201217 counties in Illinois; 8 counties in Kentucky; 7 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Mar 14, 2012, 1:56 PM CDT for 17 counties in Illinois; 8 counties in Kentucky; 7 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 14, 2012, 1:56 PM CDT (18:56 UTC)
Expired
Mar 14, 2012, 4:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 32 counties

Alexander County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Saline County, IL, Union County, IL, Washington County, IL, Williamson County, IL, Ballard County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Livingston County, KY, McCracken County, KY, Bollinger County, MO, Cape Girardeau County, MO, Mississippi County, MO, New Madrid County, MO, Perry County, MO, Scott County, MO, Stoddard County, MO

The radar

The Paducah radar (KPAH), 59 km from the middle of the area, began a volume at 19:00 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

Little Rock, AR (KLZK), launched 12:00Z, 6.9 hours before the alert went out and 272 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, Little Rock, AR at 12:00Z on 2012-03-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2183 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, Little Rock, AR at 12:00Z on 2012-03-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -42 square meters per square second.1939Sfc1 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
2183 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
638 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-42 m²/s²
0-3 km storm-relative helicity
-15 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.

894 
ACUS11 KWNS 141856
SWOMCD
SPC MCD 141856 
KYZ000-ILZ000-MOZ000-TNZ000-142100-

MESOSCALE DISCUSSION 0253
NWS STORM PREDICTION CENTER NORMAN OK
0156 PM CDT WED MAR 14 2012

AREAS AFFECTED...SWRN MO...FAR SRN IL...FAR WRN KY

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 141856Z - 142100Z

A CONDITIONAL THREAT FOR LARGE HAIL/DMGG WINDS WILL EXIST LATE THIS
AFTERNOON AND EVENING ACROSS PORTIONS OF SWRN MO...FAR SRN IL...AND
FAR WRN KY. EXPECTED ISOLATED NATURE OF THE THREAT LIMITS THE NEED
FOR A WW.

TEMPERATURES HAVE WARMED INTO THE UPPER 70S AND LOW 80S AND MOISTURE
ADVECTION ASSOCIATED WITH RETURN FLOW ACROSS A BROAD WARM SECTOR HAS
KEPT DEWPOINTS IN THE MID 60S. ADDITIONALLY... NEAR DRY ADIABATIC
LAPSE RATES ARE PRESENT ABOVE 700 MB. AS A RESULT...AN UNCAPPED
ENVIRONMENT WITH SBCAPE VALUES AOA 2500 J/KG EXISTS OVER THE REGION.
HOWEVER...THE SEVERE THREAT IS EXPECTED TO BE LIMITED...OWING TO THE
LACK OF STRONG FORCING AND EFFECTIVE BULK SHEAR OF 25-30 KT /LOWER
MARGINS FOR PERSISTENT STORMS/. CONSEQUENTLY...AN ISOLATED THREAT
FOR LARGE HAIL AND DMGG WINDS IS POSSIBLE BUT THE LIMITED COVERAGE
WILL PRECLUDE THE NEED FOR A WW.

..MOSIER.. 03/14/2012

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

ATTN...WFO...PAH...MEG...LSX...

LAT...LON   36498957 36468989 36779024 37379029 38348999 38478939
            38178830 37268807 36548877 36498957

Nearby

Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Kentucky, 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.