Alert archive / Tennessee / Mesoscale Discussions in 2011

Mesoscale Discussion 963

May 25, 20117 counties in Alabama; 30 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at May 25, 2011, 3:45 PM CDT for 7 counties in Alabama; 30 counties in Tennessee. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
May 25, 2011, 3:45 PM CDT (20:45 UTC)
Expired
May 25, 2011, 5:15 PM CDT
In force
90 min
Issued by
the Storm Prediction Center
All 37 counties

Colbert County, AL, Franklin County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Morgan County, AL, Bedford County, TN, Benton County, TN, Cannon County, TN, Cheatham County, TN, Coffee County, TN, Davidson County, TN, Decatur County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Moore County, TN, Perry County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 108 km from the middle of the area, began a volume at 20:46 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, 8.8 hours before the alert went out and 95 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 2011-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1690 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 2011-05-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 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
1690 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
863 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

112 
ACUS11 KWNS 252045
SWOMCD
SPC MCD 252045 
PAZ000-WVZ000-OHZ000-MIZ000-252145-

MESOSCALE DISCUSSION 0962
NWS STORM PREDICTION CENTER NORMAN OK
0345 PM CDT WED MAY 25 2011

AREAS AFFECTED...NRN OH...WRN PA

CONCERNING...TORNADO WATCH 372...

VALID 252045Z - 252145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 372 CONTINUES.

THE SEVERE THREAT CURRENTLY IN THE NRN PART OF WW 372 IS EXPECTED TO
DEVELOP EWD ACROSS NRN OH AND MAY REACH WRN PA BY EARLY THIS
EVENING. THE STRONGER CELLS MAY HAVE A TORNADO THREAT. WIND DAMAGE
AND HAIL WILL BE LIKELY WITH THE MORE INTENSE STORMS. WW ISSUANCE
WILL BE POSSIBLE TO THE EAST OF TORNADO WATCH 372.

A CLUSTER OF STRONG TO SEVERE THUNDERSTORMS IS ONGOING IN NRN OH
ALONG THE NOSE OF A 35 TO 45 KT LOW-LEVEL JET. THIS FEATURE IS
FORECAST TO MOVE EWD INTO CNTRL OH WHERE A GRADIENT OF MODERATE
INSTABILITY IS LOCATED. MESOANALYSIS ESTIMATED MLCAPE VALUES RANGE
FROM 2000 J/KG IN CNTRL OH TO ABOUT 1000 J/KG IN NE OH. THIS
ENVIRONMENT ALONG WITH MODERATE DEEP LAYER SHEAR PROFILES EVIDENT ON
THE CLEVELAND WSR-88D VWP SHOULD SUPPORT A SEVERE THREAT. WIND
DAMAGE WILL BE THE MOST LIKELY THREAT AS A LINE GRADUALLY APPROACHES
THE ERN EDGE OF WW 372. HOWEVER...A THREAT FOR TORNADOES MAY ALSO
EXIST ESPECIALLY AS LOW-LEVEL SHEAR INCREASES ACROSS THE REGION.

..BROYLES.. 05/25/2011

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

ATTN...WFO...PBZ...CLE...ILN...DTX...IWX...

LAT...LON   42108093 42058236 42128301 41878392 41478453 40808466
            40408394 40268316 40428180 40318027 40727976 41547989
            42108093

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 25, 7:31 AM CDTMesoscale DiscussionSPCCrockett, Dyer, Fayette, Gibson, Haywood, Henry and 7 more59 min
May 25, 10:18 AM CDTMesoscale DiscussionSPCBenton, Henderson, Houston, Montgomery, Stewart57 min
May 25, 11:02 AM CDTMesoscale DiscussionSPCBenton, Cheatham, Dickson, Dyer, Gibson, Henry and 10 more28 min
May 25, 11:52 AM CDTMesoscale DiscussionSPCCarroll, Chester, Crockett, Dyer, Fayette, Gibson and 11 more83 min
May 25, 12:28 PM CDTTornado Watch PDSSPCCarroll, Chester, Crockett, Decatur, Dyer, Fayette and 14 more8 hr
May 25, 3:10 PM CDTMesoscale DiscussionSPCLake, Obion, Stewart95 min
May 25, 5:56 PM CDTMesoscale DiscussionSPCCarroll, Chester, Crockett, Dyer, Fayette, Gibson and 12 more64 min
May 25, 6:25 PM CDTMesoscale DiscussionSPCClay2 hr

Nearby

Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Alabama, 2011Every mesoscale discussion in 2011

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.