Alert archive / Tennessee / Mesoscale Discussions in 2012
Mesoscale Discussion 397
The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2012, 12:29 PM CDT for 6 states. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Mar 31, 2012, 12:29 PM CDT (17:29 UTC)
- Expired
- Mar 31, 2012, 2:00 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 100 counties
Colbert County, AL, Cullman County, AL, Franklin County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Winston County, AL, Arkansas County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Lee County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, St. Francis County, AR, Woodruff County, AR, Dade County, GA, Dunklin County, MO, Alcorn County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Chickasaw County, MS, Coahoma County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Monroe 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, Bedford County, TN, Benton County, TN, Cannon County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Coffee County, TN, Crockett County, TN, Davidson County, TN, Decatur County, TN, DeKalb County, TN, Dickson County, TN, Dyer County, TN, Fayette County, TN, Franklin County, TN, Gibson County, TN, Giles County, TN, Grundy County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lauderdale County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Madison County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, McNairy County, TN, Moore County, TN, Perry County, TN, Rutherford County, TN, Sequatchie County, TN, Shelby County, TN, Smith County, TN, Sumner County, TN, Tipton County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN
The radar
The Memphis radar (KNQA), 101 km from the middle of the area, began a volume at 17:29 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Little Rock, AR (KLZK), launched 12:00Z, 5.5 hours before the alert went out and 115 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.
- Mixed-layer CAPE
- 1894 J/kg
- Mixed-layer CIN
- -43 J/kg
- Mixed-layer LCL
- 915 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 73 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
119
ACUS11 KWNS 311729
SWOMCD
SPC MCD 311729
TNZ000-GAZ000-ALZ000-MSZ000-MOZ000-ARZ000-311900-
MESOSCALE DISCUSSION 0397
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT SAT MAR 31 2012
AREAS AFFECTED...WRN/MIDDLE TN...NRN AL/MS...ERN AR
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 311729Z - 311900Z
THUNDERSTORM DEVELOPMENT IS PROBABLE ACROSS WRN/MIDDLE TN BY
18-19Z...WITH STORMS INCREASING IN COVERAGE OVER NRN AL/MS AND
PERHAPS ERN AR DURING THE REMAINDER OF THE AFTERNOON. LARGE HAIL AND
DAMAGING WINDS WILL BE POSSIBLE WITH THIS ACTIVITY...AND A WW WILL
LIKELY BE NEEDED OVER PORTIONS OF THE REGION.
MIDDAY WV IMAGERY SHOWS AN UPPER DISTURBANCE MOVING SEWD TOWARD THE
LWR/MID OH VALLEY...WITH A POSITIVE TILT TROUGH AXIS EXTENDING SWWD
INTO ERN TX. AT THE SURFACE...AN AREA OF LOW PRESSURE IS EXITING THE
MID-ATLANTIC...WITH A COLD FRONT TRAILING WWD INTO TN...WHICH
TRANSITIONS INTO A WARM FRONT EXTENDING NWD INTO THE LWR MO VALLEY.
VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES ALONG THE TN
PORTION OF THE COLD FRONT...WHICH IS ALLOWING SURFACE TEMPERATURES
TO WARM INTO THE MID TO UPR 70S ACROSS THE REGION. THIS
HEATING/DESTABILIZATION COMBINED WITH LOW TO MID 60S DEWPOINTS AND
MIDLEVEL LAPSE RATES IN EXCESS OF 7.5 C/KM WILL FAVOR STRONG
INSTABILITY THIS AFTERNOON...WITH MLCAPE VALUES NEAR 2500 J/KG.
GIVEN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE ALONG THE FRONT AND
POSSIBLE LARGE-SCALE FORCING FOR ASCENT WITH THE UPPER
TROUGH...THUNDERSTORM INITIATION APPEARS PROBABLE OVER WRN/MIDDLE TN
DURING THE NEXT HR OR TWO. STORMS ARE THEN FORECAST TO SPREAD S INTO
PORTIONS OF NRN AL/MS DURING THE REMAINDER OF THE AFTERNOON. THOUGH
LOW-LEVEL FLOW IS NOT PARTICULARLY STRONG...MIDLEVEL NWLY WINDS FROM
30-40 KT WILL YIELD SUFFICIENT DEEP-LAYER VERTICAL WIND SHEAR FOR
ORGANIZED MULTICELL CLUSTERS. LARGE BUOYANCY AND STEEP LAPSE RATES
WILL FAVOR SVR HAIL...IN ADDITION TO DAMAGING DOWNBURST WINDS.
..GARNER.. 03/31/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG...JAN...LZK...
LAT...LON 36169026 36578560 34938530 34008681 33669136 34979180
36169026SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 31, 12:47 PM CDT | Severe Thunderstorm Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 8 hr |
| Mar 31, 3:02 PM CDT | Mesoscale Discussion | SPC | Colbert, Jackson, Lauderdale, Lawrence, Limestone, Madison | 58 min |
| Mar 31, 5:00 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Colbert and 22 more | 30 min |
| Mar 31, 5:04 PM CDT | Severe Thunderstorm Watch | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Etowah and 12 more | 3 hr |
| Mar 31, 5:11 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Independence and 7 more | 64 min |
| Mar 31, 6:18 AM CDT | Mesoscale Discussion | SPC | Brooks, Decatur, Grady, Seminole, Thomas | 117 min |
Nearby
Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Arkansas, 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.