Alert archive / Tennessee / Mesoscale Discussions in 2011

Mesoscale Discussion 2176

September 14, 20119 counties in Mississippi; 17 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Sep 14, 2011, 12:44 PM CDT for 9 counties in Mississippi; 17 counties in Tennessee. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Sep 14, 2011, 12:44 PM CDT (17:44 UTC)
Expired
Sep 14, 2011, 2:15 PM CDT
In force
91 min
Issued by
the Storm Prediction Center
All 26 counties

Alcorn County, MS, Benton County, MS, DeSoto County, MS, Marshall County, MS, Prentiss County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Perry County, TN, Shelby County, TN, Tipton County, TN, Wayne County, TN

The radar

The Memphis radar (KNQA), 70 km from the middle of the area, began a volume at 17:44 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

Little Rock, AR (KLZK), launched 12:00Z, 5.7 hours before the alert went out and 89 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, Little Rock, AR at 12:00Z on 2011-09-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2392 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, Little Rock, AR at 12:00Z on 2011-09-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
2392 J/kg
Mixed-layer CIN
-148 J/kg
Mixed-layer LCL
1548 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
118 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.

318 
ACUS11 KWNS 141745
SWOMCD
SPC MCD 141744
TNZ000-ALZ000-MSZ000-ARZ000-141915-

MESOSCALE DISCUSSION 2176
NWS STORM PREDICTION CENTER NORMAN OK
1244 PM CDT WED SEP 14 2011

AREAS AFFECTED...WRN TN...NRN MS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 141744Z - 141915Z

AN ISOLATED SEVERE THREAT WILL LIKELY CONTINUE ACROSS WRN TN AND MAY
EXPAND SWD INTO NRN MS THIS AFTERNOON. HAIL AND A MARGINAL WIND
DAMAGE THREAT MAY OCCUR WITH THE STRONGER CELLS. WW ISSUANCE IS NOT
EXPECTED ACROSS THE REGION.

A BROKEN LINE OF THUNDERSTORMS ONGOING FROM NEAR THE BOOTHEEL OF MO
SWD ACROSS WRN TN IS LOCATED TO THE NORTHEAST OF A SFC LOW NEAR THE
NRN EDGE OF A PLUME OF MOISTURE. SFC DEWPOINTS NEAR 70 F ALONG THE
MOIST AXIS ARE HELPING TO CREATE A POCKET OF MODERATE TO STRONG
INSTABILITY ACROSS NRN MS EXTENDING NWD INTO WRN TN. SBCAPE VALUES
ARE ESTIMATED IN THE 2000 TO 3000 J/KG RANGE ACROSS MUCH OF THE MCD
AREA. THIS ALONG WITH LARGE-SCALE ASCENT ASSOCIATED WITH A SHORTWAVE
TROUGH MOVING INTO THE MID-MS VALLEY WILL LIKELY SUPPORT THE
CONVECTION AS IT MOVES EWD INTO SCNTRL TN THIS AFTERNOON. WSR-88D
VWPS IN WRN TN CURRENTLY SHOW 0-6 KM SHEAR VALUES IN THE 30 35 KT
RANGE SUGGESTING ENOUGH SHEAR EXISTS FOR A MARGINAL SEVERE THREAT.
ALTHOUGH HAIL MAY BE THE GREATEST THREAT...A MARGINAL WIND DAMAGE
THREAT COULD ALSO EXIST ESPECIALLY AS THE CELLS BECOME INCREASINGLY
SFC-BASED THIS AFTERNOON.

..BROYLES.. 09/14/2011

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

ATTN...WFO...OHX...HUN...MEG...

LAT...LON   34478993 34358917 34758794 35358759 35888773 36178843
            36048948 35788989 35409003 34989009 34478993

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 14, 2:36 PM CDTMesoscale DiscussionSPCLake84 min

Nearby

Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Mississippi, 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.