Alert archive / Mississippi / Mesoscale Discussions in 2011
Mesoscale Discussion 348
The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2011, 2:52 PM CDT for 6 counties in Alabama; 10 parishes in Louisiana; 35 counties in Mississippi. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Apr 4, 2011, 2:52 PM CDT (19:52 UTC)
- Expired
- Apr 4, 2011, 4:45 PM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
All 51 counties
Choctaw County, AL, Fayette County, AL, Greene County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Avoyelles Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, Franklin Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Rapides Parish, LA, Richland Parish, LA, Tensas Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Franklin County, MS, Hinds County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Warren County, MS, Wayne County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 11 km from the middle of the area, began a volume at 19:55 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
Jackson, MS (KJAN), launched 12:00Z, 7.9 hours before the alert went out and 6 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
- 1411 J/kg
- Mixed-layer CIN
- -115 J/kg
- Mixed-layer LCL
- 704 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 223 m²/s²
- 0-3 km storm-relative helicity
- 425 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 2.7
The text
As transmitted, in the capitals the NWS used until 2016.
240
ACUS11 KWNS 041953
SWOMCD
SPC MCD 041952
ALZ000-MSZ000-LAZ000-042145-
MESOSCALE DISCUSSION 0348
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT MON APR 04 2011
AREAS AFFECTED...LA...MS...NRN AL
CONCERNING...TORNADO WATCH 91...93...
VALID 041952Z - 042145Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 91...93...CONTINUES.
18 SOUNDINGS SHOW RELATIVELY STRONG INSTABILITY IN PLACE FROM LA
INTO MS WITH MUCAPE AROUND 3000 J/KG. ALSO DEPICTED IN THE SOUNDINGS
WAS RELATIVELY STEEP LAPSE RATES PROFILES ALOFT WHICH SHOULD LEAD TO
ROBUST UPDRAFTS.
EARLIER STORMS THAT MOVED ACROSS NRN MS AND INTO TN HAVE LEFT A
TRAILING OUTFLOW BOUNDARY OVER NRN AND CNTRL MS...TRAILING SWWD TO
THE COLD FRONT OVER NRN LA. RECENTLY...STORMS OVER NRN LA HAVE
BECOME INTENSE SUPERCELLS WITH INDICATIONS OF TORNADOES.
AS THESE STORMS CONTINUE NEWD OVER NERN LA AND CNTRL MS...THERE WILL
BE A THREAT OF TORNADOES...DAMAGING WINDS AND HAIL. A FAVORED ZONE
FOR ENHANCED LOW LEVEL SHEAR AND TORNADIC POTENTIAL WILL BE ALONG
THE OUTFLOW BOUNDARY.
ALSO NOTED IN THE MIDDAY SOUNDINGS AND VWPS WAS A MID LEVEL BACKING
OF THE WINDS. THIS MAY DISRUPT TORNADO/SUPERCELL POTENTIAL SOMEWHAT
DUE TO STORM MODE...BUT EVEN WITH A MORE LINEAR
STRUCTURE...PARTICULARLY DAMAGING WINDS MAY OCCUR ALONG WITH
EMBEDDED AREAS OF ROTATION.
..JEWELL.. 04/04/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BMX...MOB...JAN...LIX...LCH...SHV...
LAT...LON 30899273 32239226 32539191 32809028 33528899 33758779
33388739 32378777 31588862 31059067 30899273SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 4, 10:25 AM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 9 more | 2 hr |
| Apr 4, 1:03 PM CDT | Tornado Watch | SPC | Blount, Colbert, Cullman, DeKalb, Fayette, Franklin and 16 more | 7 hr |
| Apr 4, 4:28 PM CDT | Mesoscale Discussion | SPC | Autauga, Baldwin, Bullock, Butler, Calhoun, Chambers and 29 more | 62 min |
| Apr 4, 4:55 PM CDT | Tornado Watch | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 28 more | 6 hr |
| Apr 4, 5:28 PM CDT | Tornado Watch | SPC | Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more | 7 hr |
| Apr 4, 6:50 PM CDT | Mesoscale Discussion | SPC | Autauga, Baldwin, Bibb, Blount, Butler, Calhoun and 36 more | 85 min |
| Apr 4, 7:44 AM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more | 8 hr |
| Apr 4, 10:53 AM CDT | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more | 7 hr |
| Apr 4, 11:20 AM CDT | Mesoscale Discussion | SPC | Beauregard, Bienville, Caldwell, Claiborne, De Soto, Grant and 12 more | 115 min |
| Apr 4, 7:22 AM CDT | Tornado Watch | SPC | Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more | 7 hr |
Nearby
Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Louisiana, 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.