Mesoscale Discussion 1473

Issued

Aug 11, 2021, 7:27 AM CDT (12:27 UTC)

Expired

Aug 11, 2021, 9:30 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Minneapolis radar (KMPX), 85 km from the middle of the area, began a volume at 12:30 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.

938 
ACUS11 KWNS 111228
SWOMCD
SPC MCD 111227 
WIZ000-MNZ000-111430-

Mesoscale Discussion 1473
NWS Storm Prediction Center Norman OK
0727 AM CDT Wed Aug 11 2021

Areas affected...Southeast MN...West-Central WI

Concerning...Severe potential...Watch unlikely 

Valid 111227Z - 111430Z

Probability of Watch Issuance...20 percent

SUMMARY...Increasing thunderstorm coverage and intensity is possible
from southeast MN into west-central WI over the next few hours.
Severe storms may be delayed until early afternoon/farther east, but
a conditional risk exists over southeast MN into west-central WI now
and convective trends across the region are being watched closely.

DISCUSSION...Primary forcing for ascent attendant to the deep
shortwave trough moving into western Ontario and the Upper Midwest
is currently spreading across MN. A few deeper updrafts have
developed across central/east-central MN as this ascent spreads
eastward. Thus far, updrafts have been transient and relatively
shallow, likely as a result of only modest buoyancy. However, the
low-level moisture advection ongoing from the mid MS Valley into
southern MN and central/southern WI is bring stronger buoyancy
northward. As a result, the overall expectation is for a gradual
increase in thunderstorm coverage and strength over the next several
hours. Convective inhibition is still present across much of the
region and storms will likely remain elevated initially before
gradually becoming rooted closely to the surface over time. This
transition may not occur until early this afternoon, but the
strength of the buoyancy coupled with the approaching forcing for
ascent may result in earlier severe storm development. As such,
convective trends across the region will be monitored closely for
signs that increases in storm coverage and intensity merit watch
issuance.

..Mosier/Guyer.. 08/11/2021

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

ATTN...WFO...DLH...ARX...MPX...

LAT...LON   44159389 45559319 46089204 46019084 45599055 43789154
            43589289 43699368 44159389

Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Wisconsin, 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.