Alert archive / Tennessee / Mesoscale Discussions in 2014

Mesoscale Discussion 1666

September 2, 201420 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2014, 7:05 PM EDT for 20 counties in Tennessee. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Sep 2, 2014, 7:05 PM EDT (23:05 UTC)
Expired
Sep 2, 2014, 8:00 PM EDT
In force
55 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Anderson County, TN, Bedford County, TN, Campbell County, TN, Cannon County, TN, Claiborne County, TN, Cumberland County, TN, DeKalb County, TN, Hickman County, TN, Knox County, TN, Maury County, TN, Morgan County, TN, Putnam County, TN, Roane County, TN, Rutherford County, TN, Scott County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN

The radar

The Nashville radar (KOHX), 65 km from the middle of the area, began a volume at 23:05 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

Nashville Metro, TN (KBNA), launched 12:00Z, 11.1 hours before the alert went out and 63 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 2014-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1661 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 2014-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 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
1661 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
808 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 2, 4:49 PM EDTMesoscale DiscussionSPCAnderson, Bedford, Benton, Bledsoe, Campbell, Cannon and 40 more56 min

Nearby

Mesoscale Discussions in Tennessee, 2014Every mesoscale discussion in 2014

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.