Alert archive / Kentucky / Mesoscale Discussions in 2012

Mesoscale Discussion 709

May 5, 20127 counties in Illinois; 7 counties in Indiana; 25 counties in Kentucky

The Storm Prediction Center issued this mesoscale discussion at May 5, 2012, 12:55 AM CDT for 7 counties in Illinois; 7 counties in Indiana; 25 counties in Kentucky. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 5, 2012, 12:55 AM CDT (05:55 UTC)
Expired
May 5, 2012, 2:30 AM CDT
In force
95 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 39 counties

Edwards County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Saline County, IL, Wabash County, IL, White County, IL, Gibson County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Adair County, KY, Breckinridge County, KY, Bullitt County, KY, Butler County, KY, Casey County, KY, Daviess County, KY, Edmonson County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Hart County, KY, Henderson County, KY, Hopkins County, KY, Larue County, KY, Marion County, KY, McLean County, KY, Meade County, KY, Muhlenberg County, KY, Nelson County, KY, Ohio County, KY, Taylor County, KY, Union County, KY, Washington County, KY, Webster County, KY

The radar

The Louisville radar (KLVX), 81 km from the middle of the area, began a volume at 05:57 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

Nashville Metro, TN (KBNA), launched 00:00Z, 5.9 hours before the alert went out and 177 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, Nashville Metro, TN at 00:00Z on 2012-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1078 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, Nashville Metro, TN at 00:00Z on 2012-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
1078 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
1542 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.6

Open this sounding in Storm Lab

The text

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

875 
ACUS11 KWNS 050555
SWOMCD
SPC MCD 050555 
KYZ000-INZ000-ILZ000-050730-

MESOSCALE DISCUSSION 0709
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT SAT MAY 05 2012

AREAS AFFECTED...SERN IL...SRN IN...NWRN KY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 050555Z - 050730Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...STORMS SHOULD PERSIST OVER MUCH OF THE AREA...WITH A
THREAT OF DAMAGING WIND GUSTS AND MARGINAL HAIL.

DISCUSSION...SEVERAL CLUSTERS OF STORMS WERE ONGOING FROM SRN IL
INTO CNTRL KY. OUTFLOW FROM THE CNTRL/ERN KY STORMS CURRENTLY TRAILS
WWD ALONG OR JUST N OF THE OH RIVER AND ACROSS SWRN IND. AMPLE
MOISTURE AND INSTABILITY EXIST S OF THE BOUNDARY AND WSWLY LOW LEVEL
FLOW WILL MAINTAIN A FAVORABLE FLUX INTO THE DEVELOPING STORMS.
INDICATIONS ARE THAT THE IL STORMS MAY PERSIST SEWD ALONG THE
BOUNDARY WITH A WIND THREAT. THIS ENTIRE AREA IS BEING HELPED ALONG
BY WEAK MIDLEVEL SPEED MAX WITH 30-35 KT FLOW HELPING TO PUSH STORMS
ALONG AND CREATE ENOUGH DEEP SHEAR FOR FORWARD PROPAGATION. HIGH
PWAT ENVIRONMENT WILL FURTHER OUTFLOW PRODUCTION.

..JEWELL.. 05/05/2012

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

ATTN...WFO...LMK...IND...PAH...

LAT...LON   37098611 37268752 37538843 37918873 38308857 38528800
            38478722 38028597 37938516 37388481 37108506 37098611

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 7:57 PM CDTMesoscale DiscussionSPCBond, Calhoun, Christian, Clay, Clinton, Crawford and 25 more63 min
May 4, 10:18 PM CDTMesoscale DiscussionSPCBond, Calhoun, Clinton, Franklin, Greene, Hamilton and 11 more87 min
May 4, 10:35 PM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Clinton, Edwards, Fayette, Franklin and 24 more8 hr
May 5, 5:06 AM CDTMesoscale DiscussionSPCGallatin, Hardin, White114 min
May 5, 2:49 AM CDTSevere Thunderstorm WatchSPCPosey, Spencer, Vanderburgh, Warrick4 hr

Nearby

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