Alert archive / Arkansas / Mesoscale Discussions in 2017

Mesoscale Discussion 564

April 26, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2017, 4:23 PM CDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Apr 26, 2017, 4:23 PM CDT (21:23 UTC)
Expired: Apr 26, 2017, 5:30 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 52 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Ouachita County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, St. Francis County, AR, Union County, AR, Woodruff County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Bolivar County, MS, Coahoma County, MS, Quitman County, MS, Tunica County, MS, Washington County, MS, Angelina County, TX, Nacogdoches County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX

The radar

The Little Rock radar (KLZK), 87 km from the middle of the area, began a volume at 21:25 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.

The nearest sounding before it

Little Rock, AR (KBYH), launched 12:00Z, 9.4 hours before the alert went out and 168 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: 271 J/kg
Mixed-layer CIN: -181 J/kg
Mixed-layer LCL: 821 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 129 m²/s²
0-3 km storm-relative helicity: 160 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 25, 10:51 PM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Madison, Washington	54 min
Apr 25, 11:27 PM CDT	Severe Thunderstorm Watch	SPC	Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more	7 hr
Apr 26, 1:42 AM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Crawford, Franklin, Johnson and 10 more	2 hr
Apr 26, 5:37 AM CDT	Mesoscale Discussion	SPC	Conway, Crawford, Franklin, Garland, Howard, Johnson and 14 more	113 min
Apr 26, 6:00 AM CDT	Severe Thunderstorm Watch	SPC	Baxter, Boone, Carroll, Conway, Crawford, Franklin and 23 more	7 hr
Apr 26, 7:29 AM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Conway, Crawford, Franklin and 23 more	2 hr
Apr 26, 9:39 AM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 47 more	36 min
Apr 26, 10:08 AM CDT	Tornado Watch	SPC	Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 51 more	7 hr
Apr 26, 1:05 PM CDT	Mesoscale Discussion	SPC	Clark, Columbia, Dallas, Grant, Hempstead, Hot Spring and 9 more	85 min
Apr 26, 3:53 PM CDT	Mesoscale Discussion	SPC	Clay	97 min
Apr 26, 4:44 PM CDT	Tornado Watch	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 11 more	5 hr
Apr 26, 5:02 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	6 hr
Apr 26, 6:10 PM CDT	Mesoscale Discussion	SPC	Mississippi	95 min

Nearby

Mesoscale Discussions in Arkansas, 2017 Mesoscale Discussions in Louisiana, 2017 Mesoscale Discussions in Texas, 2017 Every mesoscale discussion in 2017

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.