Alert archive / Tennessee / Mesoscale Discussions in 2012

Mesoscale Discussion 460

April 5, 201220 counties in Mississippi; Pemiscot County, Missouri; 22 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2012, 2:22 PM CDT for 20 counties in Mississippi; Pemiscot County, Missouri; 22 counties in Tennessee. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Apr 5, 2012, 2:22 PM CDT (19:22 UTC)
Expired
Apr 5, 2012, 3:15 PM CDT
In force
53 min
Issued by
the Storm Prediction Center
All 43 counties

Pemiscot County, MO, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Yalobusha County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Stewart County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 56 km from the middle of the area, began a volume at 19:23 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, 7.4 hours before the alert went out and 94 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 2012-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 42 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 2012-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -41 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
42 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
1448 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
-41 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

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

446 
ACUS11 KWNS 051922
SWOMCD
SPC MCD 051922 
ALZ000-TNZ000-KYZ000-MSZ000-MOZ000-ARZ000-052015-

MESOSCALE DISCUSSION 0460
NWS STORM PREDICTION CENTER NORMAN OK
0222 PM CDT THU APR 05 2012

AREAS AFFECTED...NRN MS...WRN TN...FAR NERN AR...MO BOOTHEEL

CONCERNING...SEVERE THUNDERSTORM WATCH 145...

VALID 051922Z - 052015Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 145
CONTINUES.

SURFACE ANALYSIS AT 18-19Z SHOWS A LOW PRESSURE CENTER OVER NWRN
TN...WITH A COLD FRONT ARCING SEWD INTO AL...AND A STATIONARY FRONT
EXTENDING EWD INTO MIDDLE AND ERN TN. SHORT-LIVED TORNADOES HAVE
OCCURRED OVER THE MO BOOTHEEL DURING THE PAST 1-2 HRS NEAR THE
SURFACE LOW AND MIDLEVEL VORTICITY MAX. HOWEVER...GIVEN THE INCREASE
IN STORM MERGERS AND RAIN COOLED SURFACE AIRMASS...THIS THREAT MAY
END FAIRLY SOON. OTHERWISE...LOW-LEVEL MOIST AXIS WITH SURFACE
DEWPOINTS IN THE MID TO UPR 50S EXTENDS NWWD FROM THE TN VALLEY INTO
SERN MO. GIVEN COLD MIDLEVEL TEMPERATURES ABOVE THIS
MOISTURE...MODERATELY STEEP LAPSE RATES AND MLCAPE VALUES FROM
500-1000 J/KG WILL CONTINUE TO SUPPORT A RISK FOR LARGE HAIL.

..GARNER.. 04/05/2012

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

ATTN...WFO...OHX...HUN...PAH...MEG...JAN...

LAT...LON   36508983 36508768 33928846 33939059 36508983

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 5, 1:35 AM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Copiah, Franklin, Hinds and 8 more85 min
Apr 5, 1:53 AM CDTTornado WatchSPCAdams, Amite, Attala, Bolivar, Carroll, Choctaw and 45 more9 hr
Apr 5, 3:30 AM CDTMesoscale DiscussionSPCAdams, Amite, Attala, Carroll, Claiborne, Copiah and 39 more2 hr
Apr 5, 3:56 AM CDTTornado WatchSPCAmite, Hancock, Harrison, Jackson, Pearl River, Pike and 2 more6 hr
Apr 5, 7:36 AM CDTMesoscale DiscussionSPCAdams, Attala, Carroll, Choctaw, Claiborne, Clarke and 44 more54 min
Apr 5, 9:14 AM CDTSevere Thunderstorm WatchSPCGreene, Perry, Wayne8 hr
Apr 5, 10:41 AM CDTMesoscale DiscussionSPCGreene, Wayne94 min
Apr 5, 10:43 AM CDTSevere Thunderstorm WatchSPCClarke, Covington, Forrest, Franklin, Jasper, Jefferson Davis and 7 more4 hr
Apr 5, 12:09 PM CDTMesoscale DiscussionSPCAlcorn, Benton, DeSoto, Itawamba, Lafayette, Lee and 8 more96 min
Apr 5, 12:18 PM CDTSevere Thunderstorm WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more5 hr
Apr 5, 12:54 PM CDTMesoscale DiscussionSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Claiborne and 23 more96 min
Apr 5, 1:21 PM CDTSevere Thunderstorm WatchSPCAnderson, Bedford, Benton, Bledsoe, Blount, Bradley and 61 more8 hr
Apr 5, 3:06 PM CDTMesoscale DiscussionSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Campbell and 60 more54 min

Nearby

Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Missouri, 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; radar from the NEXRAD Level II archive.