Alert archive / Arkansas / Mesoscale Discussions in 2021

Mesoscale Discussion 514

May 3, 20218 counties in Arkansas

The Storm Prediction Center issued this mesoscale discussion at May 3, 2021, 10:22 PM CDT for 8 counties in Arkansas. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: May 3, 2021, 10:22 PM CDT (03:22 UTC)
Expired: May 3, 2021, 11:45 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 137

Counties Boone County, AR, Crawford County, AR, Franklin County, AR, Johnson County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Searcy County, AR

The radar

The Western Arkansas radar (KSRX), 109 km from the middle of the area, began a volume at 03:22 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

Springfield, MO (KSGF), launched 00:00Z, 3.4 hours before the alert went out and 120 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: 1558 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 972 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.1

Open this sounding in Storm Lab

The text

As transmitted.

202 
ACUS11 KWNS 040322
SWOMCD
SPC MCD 040322 
ARZ000-040445-

Mesoscale Discussion 0514
NWS Storm Prediction Center Norman OK
1022 PM CDT Mon May 03 2021

Areas affected...Portions of western into north-central AR

Concerning...Severe Thunderstorm Watch 137...

Valid 040322Z - 040445Z

The severe weather threat for Severe Thunderstorm Watch 137
continues.

SUMMARY...A focused corridor of 60-80 mph severe gusts appears
likely in the next hour or two across parts of western into
north-central Arkansas.

DISCUSSION...A cluster of storms crossing from eastern OK into
western AR has recently formed into a small bowing complex. The ASOS
at Fort Smith AR observed a 74 mph wind gust at 0253Z, and multiple
reports of wind damage have been received. 50-70+ kt outbound
velocities have been noted with this bow from the KSRX radar. Latest
tracking indicates this activity is moving quickly northeastward
around 50 kt along an instability/DCAPE gradient. The presence of
moderate to strong instability to the south of a front, steep
mid-level lapse rates, and 35-40 kt of deep-layer shear all suggest
that the bow will maintain its intensity as it moves northeastward
into north-central AR. Given the fast storm motion and rather strong
velocities noted on radar, widespread 60-80 mph wind gusts appear
likely in the next hour or two in association with this bowing
complex.

..Gleason.. 05/04/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LZK...TSA...

LAT...LON   35749433 36469318 36459257 36059226 35519291 35149411
            35749433

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 8:38 PM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Boone, Calhoun, Carroll, Clark and 60 more	2 hr
May 3, 9:10 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Calhoun, Carroll, Clark and 50 more	7 hr
May 3, 11:34 PM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Clark, Cleburne, Conway and 27 more	86 min
May 4, 1:06 AM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Crittenden, Cross, Greene, Jackson and 5 more	114 min
May 4, 1:41 AM CDT	Severe Thunderstorm Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Mississippi and 2 more	6 hr
May 4, 2:02 AM CDT	Mesoscale Discussion	SPC	Clay, Conway, Craighead, Cross, Faulkner, Garland and 16 more	88 min
May 4, 4:17 AM CDT	Mesoscale Discussion	SPC	Crittenden	88 min
May 4, 6:44 AM CDT	Mesoscale Discussion	SPC	Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 8 more	2 hr
May 4, 10:52 AM CDT	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Desha and 2 more	7 hr
May 4, 11:58 AM CDT	Mesoscale Discussion	SPC	Crittenden, Lee, Phillips	2 hr
May 4, 12:18 PM CDT	Severe Thunderstorm Watch	SPC	Phillips	5 hr
May 4, 1:59 PM CDT	Mesoscale Discussion	SPC	Cleburne, Conway, Craighead, Cross, Faulkner, Greene and 17 more	2 hr

Nearby

Mesoscale Discussions in Arkansas, 2021 Every mesoscale discussion in 2021

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.