Alert archive / Kentucky / Mesoscale Discussions in 2012

Mesoscale Discussion 1859

September 1, 2012Vanderburgh County, Warrick County, Indiana; 8 counties in Kentucky

The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2012, 9:37 PM CDT for Vanderburgh County, Warrick County, Indiana; 8 counties in Kentucky. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued
Sep 1, 2012, 9:37 PM CDT (02:37 UTC)
Expired
Sep 1, 2012, 10:00 PM CDT
In force
23 min
Issued by
the Storm Prediction Center

Counties Vanderburgh County, IN, Warrick County, IN, Caldwell County, KY, Christian County, KY, Henderson County, KY, Hopkins County, KY, McLean County, KY, Todd County, KY, Trigg County, KY, Webster County, KY

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 2.6 hours before the alert went out and 166 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 2012-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1909 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 2012-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 127 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
1909 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1040 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
160 m²/s²
Significant tornado parameter
0.9
Supercell composite
5.5

Open this sounding in Storm Lab

The text

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

651 
ACUS11 KWNS 020237
SWOMCD
SPC MCD 020237 
INZ000-KYZ000-TNZ000-020300-

MESOSCALE DISCUSSION 1859
NWS STORM PREDICTION CENTER NORMAN OK
0937 PM CDT SAT SEP 01 2012

AREAS AFFECTED...SRN KY AND SRN IND

CONCERNING...TORNADO WATCH 603...

VALID 020237Z - 020300Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 603 CONTINUES.

SUMMARY...AT LEAST A MODEST THREAT FOR ISOLATED STRONG TO DAMAGING
WIND GUSTS AND A TORNADO MAY PERSIST AN HOUR OR SO BEYOND WW
EXPIRATION TIME OF 03Z. HOWEVER...OVERALL THREAT IS NOT AS ROBUST AS
EARLIER...AND ANOTHER WW IS NOT EXPECTED BEYOND THE EXPIRATION TIME
OF 03Z.

DISCUSSION...STORMS HAVE EVOLVED INTO A PREDOMINANT LINEAR MODE
ACROSS WRN KY...BUT A COUPLE OF DISCRETE CELLS REMAIN. A FEW
ORGANIZED STRUCTURES PERSIST WITHIN THE LINE...AND LOW LEVEL SHEAR
REMAINS SUFFICIENT FOR A THREAT OF LOW LEVEL MESOCYCLONES. OVERALL
SEVERE POTENTIAL IS NOT AS ROBUST AS EARLIER THIS EVENING...AND A
GRADUAL WEAKENING TREND WILL LIKELY OCCUR AS STORMS ENCOUNTER AN
INCREASINGLY MARGINAL THERMODYNAMIC ENVIRONMENT.

..DIAL.. 09/02/2012

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

ATTN...WFO...LMK...OHX...PAH...

LAT...LON   36658797 37448795 38298765 38368704 36848717 36658797

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 1, 7:56 PM CDTMesoscale DiscussionSPCGibson, Posey, Vanderburgh, Warrick94 min
Sep 2, 2:20 PM CDTMesoscale DiscussionSPCAdair, Allen, Barren, Boyle, Casey, Clinton and 15 more115 min
Sep 2, 2:49 PM CDTTornado WatchSPCAdair, Allen, Anderson, Barren, Bath, Bourbon and 37 more7 hr
Sep 2, 6:35 PM CDTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bath, Bourbon and 34 more85 min

Nearby

Mesoscale Discussions in Kentucky, 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.