Alert archive / Tennessee / Mesoscale Discussions in 2012
Mesoscale Discussion 398
The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2012, 3:02 PM CDT for 4 states. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Mar 31, 2012, 3:02 PM CDT (20:02 UTC)
- Expired
- Mar 31, 2012, 4:00 PM CDT
- In force
- 58 min
- Issued by
- the Storm Prediction Center
All 68 counties
Colbert County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Catoosa County, GA, Dade County, GA, Murray County, GA, Walker County, GA, Whitfield County, GA, Alcorn County, MS, Benton County, MS, Marshall County, MS, Prentiss County, MS, Tippah County, MS, Tishomingo County, MS, Bedford County, TN, Benton County, TN, Bledsoe County, TN, Bradley County, TN, Cannon County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Coffee County, TN, Crockett County, TN, Cumberland 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, Hamilton County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Hickman County, TN, Humphreys 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, Meigs County, TN, Moore County, TN, Perry County, TN, Putnam County, TN, Rhea County, TN, Rutherford County, TN, Sequatchie County, TN, Smith County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN
The radar
The Nashville radar (KOHX), 126 km from the middle of the area, began a volume at 20:03 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
Nashville Metro, TN (KBNA), launched 12:00Z, 8.0 hours before the alert went out and 116 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
- 1321 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 509 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 96 m²/s²
- 0-3 km storm-relative helicity
- 52 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
971 ACUS11 KWNS 312003 SWOMCD SPC MCD 312002 TNZ000-GAZ000-ALZ000-MSZ000-MOZ000-ARZ000-312100- MESOSCALE DISCUSSION 0398 NWS STORM PREDICTION CENTER NORMAN OK 0302 PM CDT SAT MAR 31 2012 AREAS AFFECTED...WRN/MIDDLE TN...NRN MS...NRN AL...NWRN GA... CONCERNING...SEVERE THUNDERSTORM WATCH 121... VALID 312002Z - 312100Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 121 CONTINUES. MULTICELL CLUSTERS CONTINUE TO DEVELOP AND EXPAND IN COVERAGE OVER SRN PORTIONS OF MIDDLE TN. THESE STORMS WILL ENTER NRN MS AND NWRN GA DURING THE NEXT 1 TO 2 HRS. SURFACE TEMPERATURES IN THE MID TO UPR 70S...DEWPOINTS RANGING FROM LOW-MID 60S IN NRN MS TO MID 50S-NEAR 60 IN NWRN GA...AND STEEP MIDLEVEL LAPSE RATES YIELD MLCAPE VALUES FROM 1000-2000 J/KG. DEEP-LAYER VERTICAL WIND SHEAR BECOMES WEAKER WITH SWD EXTENT /I.E. 0-6 KM BULK WIND DIFFERENCE FROM 20-30 KT/...BUT SHOULD BE SUFFICIENT FOR CONTINUED RISK OF LARGE HAIL/DAMAGING WIND GUSTS GIVEN FAVORABLE THERMODYNAMICS. FARTHER W OVER WRN TN AND NRN MS...VISIBLE SATELLITE IMAGERY SHOWS AGITATED CUMULUS FIELD DEVELOPING IN RESPONSE TO STRONG SURFACE HEATING /TEMPERATURES IN THE LOW 80S/ AND STEEPENING LOW-LEVEL LAPSE RATES. GRADUAL INCREASE IN STORM COVERAGE SHOULD OCCUR AS A RESULT THROUGH THE REMAINDER OF THE AFTERNOON. COMBINATION OF MLCAPE VALUES NEAR 2500 J/KG AND EFFECTIVE BULK WIND DIFFERENCE FROM 20-30 KT WILL FAVOR A FEW SVR MULTICELL THUNDERSTORMS POSING A THREAT FOR LARGE HAIL AND DAMAGING WIND GUSTS. ..GARNER.. 03/31/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MRX...FFC...OHX...HUN...MEG... LAT...LON 36218965 36308470 34578469 34488965 36218965
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 31, 12:29 PM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Franklin, Jackson, Lauderdale, Lawrence and 6 more | 91 min |
| Mar 31, 12:47 PM CDT | Severe Thunderstorm Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 8 hr |
| 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, 6:18 AM CDT | Mesoscale Discussion | SPC | Brooks, Decatur, Grady, Seminole, Thomas | 117 min |
Nearby
Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Mississippi, 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.