Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 732

May 6, 2012Sumter County, Alabama; 25 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 1:38 PM CDT for Sumter County, Alabama; 25 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 6, 2012, 1:38 PM CDT (18:38 UTC)
Expired: May 6, 2012, 3:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 26 counties

Sumter County, AL, Attala County, MS, Carroll County, MS, Choctaw County, MS, Clarke County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Jasper County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Tallahatchie County, MS, Webster County, MS, Winston County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 103 km from the middle of the area, began a volume at 18:41 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

Jackson, MS (KJAN), launched 12:00Z, 6.6 hours before the alert went out and 107 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1747 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 921 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 64 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.

042 
ACUS11 KWNS 061838
SWOMCD
SPC MCD 061838 
ALZ000-MSZ000-062045-

MESOSCALE DISCUSSION 0732
NWS STORM PREDICTION CENTER NORMAN OK
0138 PM CDT SUN MAY 06 2012

AREAS AFFECTED...CNTRL MS AND FAR W-CNTRL AL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 061838Z - 062045Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED STRONG TO SEVERE STORMS WILL BE POSSIBLE THROUGH
THE REMAINDER OF THE AFTERNOON. PERIODIC INSTANCES OF LARGE HAIL AND
STRONG/GUSTY WINDS WILL BE POSSIBLE WITH THE STRONGEST STORMS. GIVEN
THE EXPECTED DISORGANIZED/ISOLATED NATURE OF THE CONVECTION A WW IS
NOT ANTICIPATED AT THIS TIME.

DISCUSSION...ISOLATED STRONG TO SEVERE THUNDERSTORMS HAD DEVELOPED
THIS AFTERNOON ALONG AN OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION
ACROSS THE TN VALLEY. AS THE AIR MASS HAS BECOME STRONGLY
UNSTABLE...SOME VIGOROUS UPDRAFTS WERE EVIDENT. STEEP LOW AND MID
LEVEL LAPSE RATES COMBINED WITH COLD TEMPERATURES ALOFT PER THE 12Z
JAN RAOB WILL SUPPORT LARGE HAIL PRODUCTION WITH THE STRONGER
STORMS. STORM COVERAGE IS EXPECTED TO REMAIN ISOLATED AND RATHER
PULSE-LIKE IN NATURE GIVEN WEAK DEEP LAYER SHEAR AND LACK OF
STRONGER UPPER LEVEL FORCING FOR ASCENT. ACROSS SRN AL INTO SRN
GA...A MORE SUBSTANTIAL COLD POOL FROM OVERNIGHT CONVECTION HAS
HELPED STORMS ORGANIZE INTO A LINEAR STRUCTURE ALONG THE OUTFLOW
BOUNDARY. THIS DOES NOT APPEAR TO BE THE CASE ACROSS CNTRL MS AT
THIS TIME AND THEREFORE NO WW IS ANTICIPATED AT THIS TIME GIVEN
ISOLATED/DISORGANIZED NATURE OF THE CONVECTION.

..LEITMAN.. 05/06/2012

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

ATTN...WFO...BMX...MOB...MEG...JAN...

LAT...LON   34109013 33718852 33428816 32948814 32628811 32268812
            32018830 31928869 31928907 32138979 32449020 33149053
            33969045 34109013

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 6, 12:04 PM CDT	Mesoscale Discussion	SPC	Barbour, Bullock, Butler, Choctaw, Clarke, Coffee and 17 more	86 min
May 6, 12:50 PM CDT	Severe Thunderstorm Watch	SPC	Baldwin, Butler, Clarke, Coffee, Conecuh, Covington and 8 more	5 hr
May 6, 4:41 PM CDT	Mesoscale Discussion	SPC	Baldwin	64 min

Nearby

Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Alabama, 2012 Every 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.