Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 570

April 25, 20115 counties in Arkansas; 20 counties in Mississippi; 4 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2011, 1:15 PM CDT for 5 counties in Arkansas; 20 counties in Mississippi; 4 counties in Tennessee. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2011, 1:15 PM CDT (18:15 UTC)
Expired: Apr 25, 2011, 2:15 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 29 counties

Crittenden County, AR, Cross County, AR, Lee County, AR, Phillips County, AR, St. Francis County, AR, Alcorn County, MS, Benton 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, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tunica County, MS, Union County, MS, Yalobusha County, MS, Fayette County, TN, Hardeman County, TN, McNairy County, TN, Shelby County, TN

The radar

The Memphis radar (KNQA), 65 km from the middle of the area, began a volume at 18:18 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.

Tornado Watch 206Apr 25, 4:50 PM CDT

The nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 6.3 hours before the alert went out and 9 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: 11 J/kg
Mixed-layer CIN: -189 J/kg
Mixed-layer LCL: 729 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 210 m²/s²
0-3 km storm-relative helicity: 321 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.8

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.

Issued	Product	Office	Counties	Lasted
Apr 24, 10:13 PM CDT	Mesoscale Discussion	SPC	Clark, Cleburne, Conway, Faulkner, Garland, Grant and 15 more	2 hr
Apr 24, 11:43 PM CDT	Severe Thunderstorm Watch	SPC	Hempstead, Howard, Little River, Miller, Nevada, Sevier	5 hr
Apr 25, 1:57 AM CDT	Mesoscale Discussion	SPC	Cleveland, Dallas, Jefferson, Lincoln	63 min
Apr 25, 4:41 AM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 25 more	7 hr
Apr 25, 7:23 AM CDT	Mesoscale Discussion	SPC	Calhoun, Clark, Cleveland, Columbia, Dallas, Garland and 11 more	97 min
Apr 25, 8:37 AM CDT	Mesoscale Discussion	SPC	Arkansas, Cleveland, Crittenden, Desha, Drew, Jefferson and 7 more	53 min
Apr 25, 9:17 AM CDT	Severe Thunderstorm Watch	SPC	Crittenden, Lee, Phillips, St. Francis	6 hr
Apr 25, 10:46 AM CDT	Mesoscale Discussion	SPC	Hempstead, Howard, Lafayette, Little River, Miller, Sevier	59 min
Apr 25, 11:00 AM CDT	Tornado Watch	SPC	Carroll, Clark, Crawford, Franklin, Hempstead, Howard and 13 more	7 hr
Apr 25, 1:28 PM CDT	Mesoscale Discussion	SPC	Crawford, Franklin, Howard, Johnson, Little River, Logan and 5 more	92 min
Apr 25, 3:08 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Boone, Bradley, Calhoun and 29 more	37 min
Apr 25, 3:22 PM CDT	Tornado Watch PDS	SPC	Arkansas, Baxter, Boone, Bradley, Calhoun, Clark and 50 more	8 hr
Apr 25, 4:34 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clay, Craighead, Crittenden, Cross, Greene and 11 more	56 min
Apr 25, 4:50 PM CDT	Tornado Watch PDS	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	7 hr
Apr 25, 1:48 PM CDT	Mesoscale Discussion	SPC	Bedford, Benton, Carroll, Cheatham, Davidson, Decatur and 20 more	87 min
Apr 25, 2:29 PM CDT	Severe Thunderstorm Watch	SPC	Benton, Cheatham, Davidson, Dickson, Hickman, Houston and 14 more	4 hr

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Arkansas, 2011 Mesoscale Discussions in Tennessee, 2011 Every 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.