Alert archive / Kentucky / Mesoscale Discussions in 2012

Mesoscale Discussion 1700

August 4, 201220 counties in Indiana; 21 counties in Kentucky; 21 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2012, 2:13 PM EDT for 20 counties in Indiana; 21 counties in Kentucky; 21 counties in Tennessee. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Aug 4, 2012, 2:13 PM EDT (18:13 UTC)
Expired
Aug 4, 2012, 3:45 PM EDT
In force
92 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 62 counties

Brown County, IN, Crawford County, IN, Daviess County, IN, Dubois County, IN, Floyd County, IN, Gibson County, IN, Greene County, IN, Harrison County, IN, Jackson County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Orange County, IN, Perry County, IN, Pike County, IN, Scott County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Washington County, IN, Allen County, KY, Breckinridge County, KY, Butler County, KY, Christian County, KY, Daviess County, KY, Edmonson County, KY, Grayson County, KY, Hancock County, KY, Hardin County, KY, Henderson County, KY, Hopkins County, KY, Logan County, KY, McLean County, KY, Meade County, KY, Muhlenberg County, KY, Ohio County, KY, Simpson County, KY, Todd County, KY, Trigg County, KY, Warren County, KY, Webster County, KY, Cheatham County, TN, Davidson County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Perry County, TN, Robertson County, TN, Rutherford County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 6.2 hours before the alert went out and 128 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 12:00Z on 2012-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2994 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 12:00Z on 2012-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 89 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
2994 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
630 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
89 m²/s²
0-3 km storm-relative helicity
88 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.

542 
ACUS11 KWNS 041813
SWOMCD
SPC MCD 041813 
KYZ000-INZ000-TNZ000-ALZ000-041945-

MESOSCALE DISCUSSION 1700
NWS STORM PREDICTION CENTER NORMAN OK
0113 PM CDT SAT AUG 04 2012

AREAS AFFECTED...SRN IND/PORTIONS OF KY/TN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 041813Z - 041945Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SVR TSTMS PRODUCING DAMAGING DOWNBURST WINDS AND
HAIL ARE POSSIBLE THRU THE AFTERNOON HOURS. DUE TO THE LOCALIZED
NATURE OF THE SVR THREAT...A WW IS NOT ANTICIPATED AT THIS TIME.

DISCUSSION...STG TSTMS CONTINUE TO DEVELOP IN THE VICINITY OF A
SURFACE CONFLUENCE ZONE CHARACTERIZED BY STG INSTABILITY /MLCAPE OF
3000-4000 J/KG/...AND MINIMAL CINH. DISCUSSION AREA IS SOUTH OF
STRONGER MID-LEVEL FLOW...HOWEVER HIGH VALUES OF PRECIPITABLE WATER
/PWATS OF 2 INCHES OR MORE/ AND INCREASING LOW-LEVEL LAPSE RATES
EAST OF THE DEVELOPING TSTMS SUGGEST ISOLATED DAMAGING DOWNBURST
WINDS WILL BE THE MAIN THREAT. WHERE MERGING OUTFLOWS CAN BECOME
ESTABLISHED...CLUSTERS OF SVR TSTMS WITH AN ENHANCED SVR WIND THREAT
WILL BE POSSIBLE. A FEW LARGE HAIL REPORTS ARE ALSO NOT OUT OF THE
QUESTION GIVEN THE DEGREE OF INSTABILITY.

..BUNTING/THOMPSON.. 08/04/2012

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

ATTN...WFO...LMK...OHX...IND...HUN...PAH...MEG...

LAT...LON   36738801 37608771 38428757 39078701 39258625 39048577
            38458572 37808575 36598607 35498648 34988682 35138802
            36328808 36928787 36738801

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 4, 2:46 PM EDTSevere Thunderstorm WatchSPCBenton, Jasper, Lake, Newton, Porter4 hr
Aug 4, 4:57 PM EDTMesoscale DiscussionSPCBenton, Carroll, Cass, Elkhart, Fulton, Howard and 19 more63 min
Aug 4, 5:35 PM EDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more5 hr
Aug 4, 7:23 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Delaware, Elkhart and 13 more2 hr
Aug 4, 7:50 PM EDTSevere Thunderstorm WatchSPCWayne5 hr

Nearby

Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Tennessee, 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.