Mesoscale Discussion 352

Issued

Apr 9, 2021, 6:34 PM CDT (23:34 UTC)

Expired

Apr 9, 2021, 8:30 PM CDT

In force

116 min

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 81

The Tulsa radar (KINX), 79 km from the middle of the area, began a volume at 23:36 UTC, the scan nearest the moment this went out.

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• Severe Thunderstorm Watch 84Apr 9, 8:45 PM CDT

903 
ACUS11 KWNS 092334
SWOMCD
SPC MCD 092334 
MOZ000-ARZ000-OKZ000-KSZ000-TXZ000-100130-

Mesoscale Discussion 0352
NWS Storm Prediction Center Norman OK
0634 PM CDT Fri Apr 09 2021

Areas affected...Portions of central and eastern Oklahoma into
southwest Missouri

Concerning...Severe Thunderstorm Watch 81...

Valid 092334Z - 100130Z

The severe weather threat for Severe Thunderstorm Watch 81
continues.

SUMMARY...The severe threat continues across Severe Thunderstorm
Watch #081. Discrete to semi-discrete supercells will continue to
pose a risk for severe hail (including 2+ inch stones), though
severe winds are expected to gradually become the primary severe
threat as storms merge into a line.

DISCUSSION...Discrete supercells and multicellular clusters are
ongoing across much of central and north-central Oklahoma in advance
of a southeastward moving cold front. Several of these supercells
have produced severe hail over the past couple of hours, with 2+
inch stones noted across Grady and Kingfisher counties. 1500-2500
J/kg MLCAPE driven by up to 9 C/km mid-level lapse rates suggest
that large hail (including occasional 2+ inch stones) will remain
possible with any storm that can mature and maintain supercell
characteristics. Despite ample buoyancy in place, shear is
relatively weak, with 2242Z TLX VWPs showing under 30 kts of sfc-6
km bulk shear, and under 50 m2/s2 of 0-3 km SRH. Expanding
convective cold pools driven by weaker shear and linear forcing
along the front suggest that storms will gradually congeal into a
line over the next few hours. Despite winds remaining below 40 kts
in the sfc-10 km layer, microphysically driven downward momentum
transport from congealing convection may compensate to support an
increasing damaging wind threat, which may become the primary
concern over the next few hours.

Portions of southwest MO into AR have been slow to recover from the
convective overturning due to earlier storms. The current convection
from central OK into extreme southeast KS is expected to weaken
while encountering this more stable air. As such, the most intense
portion of the anticipated developing line of storms is expected to
propagate south-southeastward into south-central and southeast OK
this evening, as also supported by the latest few runs of the HRRR
and Warn-on-Forecast guidance.

..Squitieri.. 04/09/2021

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

ATTN...WFO...LZK...SGF...SHV...TSA...ICT...FWD...OUN...

LAT...LON   34219836 35389783 36329725 37089661 37459522 37469389
            37369316 36879305 36089353 35409428 34899464 34419491
            34079511 33899576 33939692 34019806 34219836

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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.