Alert archive / Arkansas / Mesoscale Discussions in 2017

Mesoscale Discussion 597

April 29, 201726 counties in Arkansas; Bolivar County, Coahoma County, Tunica County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 6:21 PM CDT for 26 counties in Arkansas; Bolivar County, Coahoma County, Tunica County, Mississippi. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Apr 29, 2017, 6:21 PM CDT (23:21 UTC)
Expired: Apr 29, 2017, 7:15 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 29 counties

Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Bolivar County, MS, Coahoma County, MS, Tunica County, MS

The radar

The Little Rock radar (KLZK), 61 km from the middle of the area, began a volume at 23:23 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 178Apr 29, 10:15 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 11.4 hours before the alert went out and 295 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: 1457 J/kg
Mixed-layer CIN: -210 J/kg
Mixed-layer LCL: 762 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 152 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 28, 10:01 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Carroll, Crawford, Franklin and 8 more	9 hr
Apr 28, 10:49 PM CDT	Mesoscale Discussion	SPC	Johnson, Logan, Pope, Searcy, Van Buren	56 min
Apr 28, 11:55 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Clay, Crawford and 12 more	95 min
Apr 29, 3:39 AM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Madison, Washington	96 min
Apr 29, 1:11 PM CDT	Mesoscale Discussion	SPC	Benton, Conway, Crawford, Franklin, Garland, Hot Spring and 15 more	2 hr
Apr 29, 5:36 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Boone, Carroll, Crawford, Franklin, Fulton and 9 more	4 hr

Nearby

Mesoscale Discussions in Arkansas, 2017 Mesoscale Discussions in Mississippi, 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.