Mesoscale Discussion 821

Issued

Jun 4, 2020, 5:14 PM CDT (22:14 UTC)

Expired

Jun 4, 2020, 6:45 PM CDT

In force

91 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Des Moines radar (KDMX), 105 km from the middle of the area, began a volume at 22:16 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.

467 
ACUS11 KWNS 042215
SWOMCD
SPC MCD 042214 
WIZ000-ILZ000-IAZ000-MNZ000-NEZ000-SDZ000-042345-

Mesoscale Discussion 0821
NWS Storm Prediction Center Norman OK
0514 PM CDT Thu Jun 04 2020

Areas affected...portions of northern/eastern Iowa...far southern
Minnesota...far southeast South Dakota

Concerning...Severe potential...Watch unlikely 

Valid 042214Z - 042345Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms are developing across northern/eastern Iowa into
far southern Minnesota. Damaging winds and large hail are the
primary severe threats. However, given the likely isolated and
marginal nature of the severe threat, a watch issuance is unlikely.

DISCUSSION...Storms are developing along and near a surface front
draped across eastern South Dakota through southwest Minnesota and
northern Iowa. A cu field has developed across the area as
convective temperatures are breached along with lifting associated
with the surface front. Zonal flow aloft is strengthening and water
vapor imagery suggests low amplitude mid-level shortwave troughs are
rotating over the region. Daytime heating has pushed surface
temperatures into the upper 80s F and low 90s F with dewpoints in
the 60s F south of the front. As a result, instability has increased
with MLCAPE of 500-1500+ J/kg now across the area per mesoanalysis,
and weaker supercells are possible with bulk shear of 30-40 knots.
Damaging winds and large hail are the main threats as storms drift
eastward. However, the environment indicates the severe coverage
will likely be more isolated with marginally severe hail/wind.

..Nauslar/Goss.. 06/04/2020

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

ATTN...WFO...MKX...DVN...ARX...MPX...DMX...FSD...OAX...

LAT...LON   41699430 42129566 42419643 43209675 44149663 44119552
            43979367 43889239 43749128 42619036 41489047 41149101
            41229241 41699430

Mesoscale Discussions in Iowa, 2020Mesoscale Discussions in Minnesota, 2020Mesoscale Discussions in Wisconsin, 2020Every mesoscale discussion in 2020

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.