Alert archive / Arkansas / Mesoscale Discussions in 2008

Mesoscale Discussion 464

March 18, 20085 states

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2008, 4:46 PM CDT for 5 states. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Mar 18, 2008, 4:46 PM CDT (21:46 UTC)
Expired: Mar 18, 2008, 5:45 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center

All 61 counties

Arkansas County, AR, Clark County, AR, Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Grant County, AR, Greene County, AR, Hempstead County, AR, Hot Spring County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Lonoke County, AR, Mississippi County, AR, Monroe County, AR, Nevada County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Muhlenberg County, KY, Trigg County, KY, Webster County, KY, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, DeSoto County, MS, Carroll County, TN, Crockett County, TN, Dyer County, TN, Gibson County, TN, Haywood County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Stewart County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 76 km from the middle of the area, began a volume at 21:49 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 132Mar 18, 5:20 PM CDT

The nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 9.8 hours before the alert went out and 131 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: 89 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 545 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 467 m²/s²
0-3 km storm-relative helicity: 574 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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
Mar 17, 7:34 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Crawford, Franklin and 11 more	56 min
Mar 17, 9:36 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Cleburne, Conway and 20 more	114 min
Mar 17, 10:16 PM CDT	Tornado Watch	SPC	Baxter, Benton, Boone, Carroll, Cleburne, Conway and 31 more	8 hr
Mar 18, 1:13 AM CDT	Mesoscale Discussion	SPC	Washington	62 min
Mar 18, 2:23 AM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Fulton, Madison and 2 more	2 hr
Mar 18, 2:46 AM CDT	Mesoscale Discussion	SPC	Baxter, Cleburne, Conway, Crawford, Faulkner, Franklin and 27 more	89 min
Mar 18, 5:54 AM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Crawford, Madison, Washington	2 hr
Mar 18, 9:26 AM CDT	Mesoscale Discussion	SPC	Calhoun, Clark, Columbia, Conway, Dallas, Garland and 19 more	2 hr
Mar 18, 10:16 AM CDT	Tornado Watch PDS	SPC	Arkansas, Clark, Clay, Cleburne, Cleveland, Columbia and 48 more	7 hr
Mar 18, 10:59 AM CDT	Tornado Watch PDS	SPC	Union	8 hr
Mar 18, 11:54 AM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Crawford, Franklin and 6 more	3 hr
Mar 18, 12:10 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleburne, Cleveland, Conway, Craighead and 47 more	2 hr
Mar 18, 1:51 PM CDT	Mesoscale Discussion	SPC	Polk, Sevier	3 hr
Mar 18, 3:54 PM CDT	Mesoscale Discussion	SPC	Clark, Cleburne, Columbia, Dallas, Faulkner, Garland and 21 more	2 hr
Mar 18, 5:19 PM CDT	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 43 more	11 hr
Mar 18, 6:06 PM CDT	Mesoscale Discussion	SPC	Clark, Clay, Cleburne, Conway, Craighead, Cross and 20 more	3 hr
Mar 18, 6:47 PM CDT	Tornado Watch	SPC	Union	9 hr

Nearby

Mesoscale Discussions in Arkansas, 2008 Mesoscale Discussions in Kentucky, 2008 Mesoscale Discussions in Tennessee, 2008 Every mesoscale discussion in 2008

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.