Alert archive / Arkansas / Mesoscale Discussions in 2009

Mesoscale Discussion 780

May 9, 20094 states

The Storm Prediction Center issued this mesoscale discussion at May 9, 2009, 12:33 PM CDT for 4 states. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: May 9, 2009, 12:33 PM CDT (17:33 UTC)
Expired: May 9, 2009, 1:30 PM CDT
In force: 57 min
Issued by: the Storm Prediction Center

All 41 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Hempstead County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, East Carroll Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Bolivar County, MS, Washington County, MS, Bowie County, TX, Camp County, TX, Cass County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Titus County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 149 km from the middle of the area, began a volume at 17:32 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 282May 9, 12:50 PM CDT

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 5.6 hours before the alert went out and 141 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: 649 J/kg
Mixed-layer CIN: -346 J/kg
Mixed-layer LCL: 829 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 207 m²/s²
0-3 km storm-relative helicity: 198 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
May 8, 7:30 PM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Greene, Mississippi, Poinsett	90 min
May 8, 9:31 PM CDT	Mesoscale Discussion	SPC	Cleburne, Conway, Crawford, Faulkner, Franklin, Izard and 15 more	89 min
May 8, 10:04 PM CDT	Mesoscale Discussion	SPC	Clay, Greene	86 min
May 8, 10:31 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Greene, Lawrence, Randolph	7 hr
May 8, 11:19 PM CDT	Mesoscale Discussion	SPC	Miller	86 min
May 9, 2:22 AM CDT	Mesoscale Discussion	SPC	Craighead, Crittenden, Cross, Greene, Mississippi, Poinsett	53 min
May 9, 12:51 PM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 22 more	7 hr
May 9, 3:25 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 13 more	65 min
May 9, 5:31 PM CDT	Mesoscale Discussion	SPC	Attala, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 28 more	89 min
May 9, 5:53 PM CDT	Severe Thunderstorm Watch	SPC	Attala, Bolivar, Carroll, Choctaw, Claiborne, Clarke and 30 more	5 hr
May 8, 9:03 PM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Clay, Coleman, Comanche and 26 more	117 min
May 8, 11:48 PM CDT	Tornado Watch	SPC	Camp, Collin, Cooke, Dallas, Delta, Denton and 28 more	5 hr
May 9, 3:20 AM CDT	Mesoscale Discussion	SPC	Camp, Collin, Cooke, Dallas, Delta, Denton and 28 more	55 min

Nearby

Mesoscale Discussions in Arkansas, 2009 Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Texas, 2009 Every mesoscale discussion in 2009

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.