Alert archive / Arkansas / Mesoscale Discussions in 2015

Mesoscale Discussion 267

April 9, 201518 counties in Arkansas; 8 parishes in Louisiana; 14 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2015, 9:23 PM CDT for 18 counties in Arkansas; 8 parishes in Louisiana; 14 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Apr 9, 2015, 9:23 PM CDT (02:23 UTC)
Expired: Apr 9, 2015, 10:30 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center

All 40 counties

Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Drew County, AR, Grant County, AR, Hempstead County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River 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, De Soto Parish, LA, Lincoln Parish, LA, Red River Parish, LA, Webster Parish, LA, Bowie County, TX, Camp County, TX, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Upshur County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 78 km from the middle of the area, began a volume at 02:26 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 nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 2.4 hours before the alert went out and 70 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: 1023 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 1138 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 144 m²/s²
0-3 km storm-relative helicity: 249 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 8.2

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 9, 8:26 PM CDT	Mesoscale Discussion	SPC	Bradley, Calhoun, Columbia, Drew, Ouachita, Union	94 min
Apr 9, 10:01 PM CDT	Mesoscale Discussion	SPC	Arkansas, Craighead, Crittenden, Cross, Desha, Greene and 8 more	119 min
Apr 10, 12:05 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, Iberia, Iberville, Lafayette and 13 more	85 min
Apr 10, 3:38 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint John the Baptist, Saint Tammany	97 min
Apr 10, 3:05 PM CDT	Mesoscale Discussion	SPC	Brewster, Culberson, Hudspeth, Jeff Davis, Pecos, Presidio and 2 more	115 min

Nearby

Mesoscale Discussions in Arkansas, 2015 Mesoscale Discussions in Texas, 2015 Mesoscale Discussions in Louisiana, 2015 Every mesoscale discussion in 2015

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.