Alert archive / Missouri / Mesoscale Discussions in 2021

Mesoscale Discussion 931

June 11, 20215 counties in Arkansas; 10 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jun 11, 2021, 8:54 PM CDT for 5 counties in Arkansas; 10 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 11, 2021, 8:54 PM CDT (01:54 UTC)
Expired: Jun 11, 2021, 11:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely 260
Chance of a watch: 20%

Counties Baxter County, AR, Benton County, AR, Boone County, AR, Carroll County, AR, Marion County, AR, Barry County, MO, Christian County, MO, Douglas County, MO, Jasper County, MO, Lawrence County, MO, McDonald County, MO, Newton County, MO, Ozark County, MO, Stone County, MO, Taney County, MO

The radar

The Springfield radar (KSGF), 64 km from the middle of the area, began a volume at 01:53 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, 1.9 hours before the alert went out and 37 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: 2670 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1310 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -54 m²/s²
0-3 km storm-relative helicity: -83 m²/s²
Significant tornado parameter: -1.0
Supercell composite: -10.3

Open this sounding in Storm Lab

The text

As transmitted.

550 
ACUS11 KWNS 120154
SWOMCD
SPC MCD 120154 
ARZ000-MOZ000-OKZ000-KSZ000-120400-

Mesoscale Discussion 0931
NWS Storm Prediction Center Norman OK
0854 PM CDT Fri Jun 11 2021

Areas affected...Southwest Missouri and Northwest Arkansas

Concerning...Severe potential...Watch unlikely 260...

Valid 120154Z - 120400Z

Probability of Watch Issuance...20 percent

SUMMARY...Strong to severe storms will continue to pose a severe
wind and hail risk for the next 1-2 hours, but the threat is
expected to become more sporadic heading into the overnight hours. A
downstream watch into northwest Arkansas is not anticipated.

DISCUSSION...A convectively reinforced outflow boundary continues to
push southward across southwest MO. Thunderstorms developing along
this boundary have shown a tendency to quickly become displaced to
the north. While this convection has been intense at times and
produced severe/damaging downburst winds, more widespread convection
has recently become confined to a single more persistent cell across
Douglas and Ozark counties. To the west, a severe cluster of storms
that moved out of southeast KS has gradually become displaced behind
the outflow boundary, and GOES IR imagery shows warming cloud tops,
indicative of a weakening trend. The expectation is that this pair
of storms will continue southward into northwest AR into the late
evening hours. The onset of diurnal cooling/stabilization and the
lack of a strong low-level jet in the region should favor a gradual
weakening trend, precluding the need for a downstream watch.
However, these storms will remain capable of severe/damaging winds
in the near term and as they approach the southern extent of WW 260.

..Moore/Dial.. 06/12/2021

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

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

LAT...LON   37299465 37189401 37199275 37109227 36689200 36269225
            36009271 36009341 36039409 36219457 36719469 37299465

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 11, 7:32 PM CDT	Mesoscale Discussion	SPC	Barry, Barton, Cedar, Christian, Dade, Dallas and 13 more	118 min

Nearby

Mesoscale Discussions in Missouri, 2021 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.