Alert archive / Arkansas / Mesoscale Discussions in 2005

Mesoscale Discussion 187

February 21, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2005, 4:29 AM CST for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Feb 21, 2005, 4:29 AM CST (10:29 UTC)
Expired: Feb 21, 2005, 6:30 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center

All 46 counties

Baxter County, AR, Boone County, AR, Clay County, AR, Cleburne County, AR, Conway County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Fulton County, AR, Greene County, AR, Independence County, AR, Izard County, AR, Marion County, AR, Mississippi County, AR, Poinsett County, AR, Pope County, AR, Searcy County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Dunklin County, MO, Pemiscot County, MO, Alcorn County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 100 km from the middle of the area, began a volume at 10:31 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.

Severe Thunderstorm Watch 23Feb 21, 5:45 AM CST

The nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 10.5 hours before the alert went out and 123 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: 887 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 720 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 4.1

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
Feb 20, 8:51 PM CST	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Cleburne, Conway, Crawford and 27 more	114 min
Feb 20, 9:10 PM CST	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Carroll, Cleburne, Conway and 29 more	6 hr
Feb 20, 11:22 PM CST	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Clay, Cleburne and 42 more	113 min
Feb 21, 12:30 AM CST	Severe Thunderstorm Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Jackson and 8 more	6 hr
Feb 21, 2:10 AM CST	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Clay, Cleburne and 43 more	95 min
Feb 21, 2:30 AM CST	Severe Thunderstorm Watch	SPC	Baxter, Boone, Cleburne, Conway, Fulton, Independence and 11 more	4 hr
Feb 21, 5:45 AM CST	Severe Thunderstorm Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	3 hr
Feb 21, 7:50 AM CST	Mesoscale Discussion	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	55 min
Feb 21, 3:58 PM CST	Mesoscale Discussion	SPC	Arkansas, Desha, Drew, Jefferson, Lincoln, Phillips	92 min
Feb 21, 12:17 PM CST	Mesoscale Discussion	SPC	Alcorn, Itawamba, Prentiss, Tippah, Tishomingo	118 min
Feb 21, 3:47 PM CST	Mesoscale Discussion	SPC	Calhoun, Chickasaw, Clay, Itawamba, Lafayette, Lee and 6 more	118 min
Feb 21, 3:00 AM CST	Severe Thunderstorm Watch	SPC	Bedford, Bledsoe, Cannon, Cheatham, Clay, Coffee and 29 more	6 hr
Feb 21, 5:13 AM CST	Mesoscale Discussion	SPC	Bedford, Bledsoe, Cannon, Cheatham, Clay, Coffee and 30 more	2 hr
Feb 21, 8:40 AM CST	Severe Thunderstorm Watch	SPC	Anderson, Bedford, Bledsoe, Bradley, Cannon, Coffee and 38 more	5 hr
Feb 21, 10:52 AM CST	Mesoscale Discussion	SPC	Blount, Bradley, Cocke, Grainger, Hamblen, Jefferson and 6 more	113 min

Nearby

Mesoscale Discussions in Arkansas, 2005 Mesoscale Discussions in Tennessee, 2005 Mesoscale Discussions in Missouri, 2005 Every mesoscale discussion in 2005

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.