Alert archive / Arkansas / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 122

April 4, 20174 states

The Storm Prediction Center issued this severe thunderstorm watch at Apr 4, 2017, 9:12 PM CDT for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Apr 4, 2017, 9:12 PM CDT (02:12 UTC)
Expired: Apr 5, 2017, 1:30 AM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 65 kt

All 44 counties

Baxter County, AR, Boone County, AR, Conway County, AR, Fulton County, AR, Garland County, AR, Hempstead County, AR, Howard County, AR, Izard County, AR, Johnson County, AR, Little River County, AR, Logan County, AR, Marion County, AR, Miller County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Scott County, AR, Searcy County, AR, Sevier County, AR, Stone County, AR, Van Buren County, AR, Yell County, AR, Christian County, MO, Dent County, MO, Douglas County, MO, Howell County, MO, Laclede County, MO, Oregon County, MO, Ozark County, MO, Phelps County, MO, Pulaski County, MO, Shannon County, MO, Taney County, MO, Texas County, MO, Webster County, MO, Wright County, MO, McCurtain County, OK, Bowie County, TX, Franklin County, TX, Red River County, TX, Titus County, TX

The radar

The Western Arkansas radar (KSRX), 69 km from the middle of the area, began a volume at 02:16 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

19 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 4, 9:24 PM CDT	Tornado Warning	SGF	Christian, Douglas, Taney, Webster, Wright	51 min
Apr 4, 9:25 PM CDT	Severe Thunderstorm Warning	LZK	Boone, Newton	35 min
Apr 4, 9:36 PM CDT	Severe Thunderstorm Warning	LZK	Johnson, Newton, Pope, Searcy	39 min
Apr 4, 9:38 PM CDT	Severe Thunderstorm Warning	LZK	Boone, Marion	37 min
Apr 4, 9:45 PM CDT	Severe Thunderstorm Warning	SHV	McCurtain	45 min
Apr 4, 9:46 PM CDT	Tornado Warning	LZK	Boone, Marion	29 min
Apr 4, 9:46 PM CDT	Tornado Warning	SGF	Ozark, Taney	44 min
Apr 4, 9:49 PM CDT	Tornado Warning	LZK	Johnson, Newton, Searcy	26 min
Apr 4, 9:49 PM CDT	Severe Thunderstorm Warning	SGF	Laclede, Phelps, Pulaski, Texas, Wright	41 min
Apr 4, 10:11 PM CDT	Tornado Warning	LZK	Boone, Marion, Newton, Searcy	34 min
Apr 4, 10:25 PM CDT	Tornado Warning	SGF	Douglas, Howell, Ozark	50 min
Apr 4, 10:26 PM CDT	Severe Thunderstorm Warning	SHV	Howard, Little River, Sevier	12 min
Apr 4, 10:29 PM CDT	Severe Thunderstorm Warning	SGF	Dent, Maries, Phelps, Pulaski, Texas	61 min
Apr 4, 10:44 PM CDT	Severe Thunderstorm Warning	LZK	Garland, Montgomery, Perry, Scott, Yell	32 min
Apr 4, 10:44 PM CDT	Severe Thunderstorm Warning	LZK	Baxter, Marion, Searcy	31 min
Apr 4, 11:01 PM CDT	Tornado Warning	SGF	Howell, Shannon, Texas	44 min
Apr 4, 11:41 PM CDT	Tornado Warning	SGF	Shannon	37 min
Apr 4, 11:50 PM CDT	Severe Thunderstorm Warning	SGF	Howell, Oregon, Shannon	37 min
Apr 4, 11:55 PM CDT	Severe Thunderstorm Warning	LZK	Fulton, Independence, Izard, Sharp, Stone	25 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 2.2 hours before the alert went out and 202 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: 326 J/kg
Mixed-layer CIN: -51 J/kg
Mixed-layer LCL: 1384 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 312 m²/s²
0-3 km storm-relative helicity: 743 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 12.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 4, 9:28 PM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Clark, Cleburne, Conway and 32 more	92 min
Apr 4, 11:38 PM CDT	Mesoscale Discussion	SPC	Baxter, Cleburne, Conway, Faulkner, Fulton, Garland and 9 more	97 min
Apr 4, 7:40 PM CDT	Mesoscale Discussion	SPC	Barry, Christian, Greene, Lawrence, Stone	65 min

Nearby

Severe Thunderstorm Watches in Arkansas, 2017 Severe Thunderstorm Watches in Missouri, 2017 Severe Thunderstorm Watches in Texas, 2017 Every severe thunderstorm watch 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.