Mesoscale Discussion 150

Issued

Mar 10, 2021, 1:32 PM CST (19:32 UTC)

Expired

Mar 10, 2021, 3:30 PM CST

In force

118 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

The Des Moines radar (KDMX), 150 km from the middle of the area, began a volume at 19:31 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.

• Tornado Watch 16Mar 10, 2:40 PM CST

480 
ACUS11 KWNS 101933
SWOMCD
SPC MCD 101932 
WIZ000-IAZ000-MNZ000-102130-

Mesoscale Discussion 0150
NWS Storm Prediction Center Norman OK
0132 PM CST Wed Mar 10 2021

Areas affected...portions of central and northern IA...southeast MN
and west-central WI

Concerning...Severe potential...Watch possible 

Valid 101932Z - 102130Z

Probability of Watch Issuance...60 percent

SUMMARY...Severe potential is increasing across parts of central IA
and southeast MN this afternoon. Thunderstorms are expected to
develop in the next 1-3 hours. A watch may be needed by 3pm.

DISCUSSION...Strong surface heating ahead of a surface low and cold
front has resulted in temperatures climbing into the mid 60s to low
70s F across much of IA this afternoon. Strong southerly low level
flow has allowed low-to-mid 50s F surface dewpoints to spread
northward across IA into southeast MN and west-central WI, aiding in
weak destabilization. The strongest instability as of 19z resides
over the western half of IA, where skies have cleared and
temperatures are warmer. Cumulus across this area have deepened over
the past hour, and some stronger reflectivity is now evident across
far northwest IA/southwest MN. This activity is elevated on the cool
side of a warm front stretching from northwest IA into west-central
WI. While this activity could result in some small hail given steep
midlevel lapse rates (7-8 C/km), any severe threat this far
west/north should remain limited. 

As the surface low continues to develop east/northeast this
afternoon, additional heating is expected in broken cloudiness
across central IA into southeast MN, resulting in weakening
inhibition. This will coincide with stronger upper forcing ejecting
across the region with the upper shortwave trough and additional
surface-based thunderstorms are expected to develop in the next 1-3
hours. Favorably curved low-level hodographs are apparent in
forecast soundings as well as in VWP data from KARX. While
instability will remain weak through this evening, strong effective
shear coupled with backed low level flow should support a couple of
storms with supercell structures capable of all severe hazards. With
time, any discrete cells that develop are expected to become more
linear during the evening as the cold front surges eastward and
deep-layer flow becomes more parallel to the surface boundary. This
could result in increasing potential for a few strong-to-severe wind
gusts into the nighttime hours.

..Leitman/Kerr.. 03/10/2021

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

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

LAT...LON   41659232 41389288 41249402 41309448 41499486 41889519
            42259527 42829525 43489475 44439399 44949309 45169228
            45079188 44909141 44639119 44159114 42209182 41659232

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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.