Mesoscale Discussion 913

Issued

Jun 10, 2021, 7:28 PM MDT (01:28 UTC)

Expired

Jun 10, 2021, 9:00 PM MDT

In force

92 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

95%

The Rapid City radar (KUDX), 136 km from the middle of the area, began a volume at 01:29 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.

• Severe Thunderstorm Watch 253Jun 10, 8:05 PM MDT

719 
ACUS11 KWNS 110129
SWOMCD
SPC MCD 110128 
SDZ000-NEZ000-110300-

Mesoscale Discussion 0913
NWS Storm Prediction Center Norman OK
0828 PM CDT Thu Jun 10 2021

Areas affected...Western/central SD/NE

Concerning...Severe potential...Watch likely 

Valid 110128Z - 110300Z

Probability of Watch Issuance...95 percent

SUMMARY...A rapid increase in thunderstorm coverage is expected near
and after 02Z. One or more clusters capable of significant damaging
wind will be possible, along with some threat for hail and possibly
a tornado or two. Watch issuance is likely.

DISCUSSION...Despite the presence of favorable instability and shear
noted in regional 00Z soundings, thunderstorm development has thus
far been suppressed across western SD/NE, likely due lingering
MLCINH and midlevel subsidence noted on WV imagery. However, the
subsidence zone is shifting eastward with time, and convection
across eastern WY has recently intensified as ascent from an
upstream shortwave trough begins to overspread the region.
Meanwhile, a cold front is accelerating eastward toward the region,
with very strong post-frontal winds noted across portions of
southern MT and northern WY. 

As ascent continues to overspread the region, the front begins to
catch up with the dryline, and the low-level jet begins to increase,
a substantial increase in storm coverage is expected near and after
02Z from far eastern WY into western SD/NE. Even though MLCINH will
be increasing with time, steep midlevel lapse rates will support
vigorous convection near and just behind the front later tonight,
with some potential for a surface-based supercell or two into the
late evening. Any surface-based storm would be capable of very large
hail and possibly a tornado. Later tonight, one or more organized
clusters are expected to develop and move quickly eastward, with
large DCAPE supporting the potential for swaths of damaging wind
even as convection becomes increasingly elevated with time. Watch
issuance is likely by 02Z in order to cover these threats.

..Dean/Dial.. 06/11/2021

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

ATTN...WFO...FSD...ABR...LBF...UNR...CYS...

LAT...LON   41600400 44670387 45830380 45870212 45880083 45550030
            44629970 43789937 42979926 42199956 41679998 41410092
            41340215 41350291 41600400

Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in Nebraska, 2021Every mesoscale discussion in 2021

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.