Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 1756

August 13, 201226 counties in Mississippi; Fayette County, Tennessee

The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2012, 5:14 PM CDT for 26 counties in Mississippi; Fayette County, Tennessee. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Aug 13, 2012, 5:14 PM CDT (22:14 UTC)
Expired
Aug 13, 2012, 6:45 PM CDT
In force
91 min
Issued by
the Storm Prediction Center
All 27 counties

Alcorn County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Marshall County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Tallahatchie County, MS, Tippah County, MS, Union County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Fayette County, TN

The radar

The Columbus AFB radar (KGWX), 96 km from the middle of the area, began a volume at 22:18 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 (KBYH), launched 12:00Z, 10.2 hours before the alert went out and 99 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 2012-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1586 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 2012-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 163 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
1586 J/kg
Mixed-layer CIN
-113 J/kg
Mixed-layer LCL
909 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
163 m²/s²
0-3 km storm-relative helicity
211 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.0

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 13, 7:48 AM CDTMesoscale DiscussionSPCAttala, Bolivar, Calhoun, Carroll, Choctaw, Clay and 20 more87 min
Aug 13, 12:38 PM CDTSevere Thunderstorm WatchSPCWayne4 hr
Aug 13, 3:15 PM CDTMesoscale DiscussionSPCBenton, Bolivar, Carroll, Coahoma, DeSoto, Grenada and 12 more30 min
Aug 13, 3:32 PM CDTSevere Thunderstorm WatchSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 26 more7 hr
Aug 13, 12:21 PM CDTMesoscale DiscussionSPCFranklin, Grundy, Lincoln, Moore24 min
Aug 13, 3:49 PM CDTMesoscale DiscussionSPCBledsoe, Bradley, Hamilton, Marion, Meigs, Rhea and 1 more56 min

Nearby

Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Tennessee, 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.