Mesoscale Discussion 181

Issued

Mar 15, 2021, 2:49 PM CDT (19:49 UTC)

Expired

Mar 15, 2021, 4:45 PM CDT

In force

116 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

237 
ACUS11 KWNS 151949
SWOMCD
SPC MCD 151949 
ILZ000-MOZ000-KSZ000-152145-

Mesoscale Discussion 0181
NWS Storm Prediction Center Norman OK
0249 PM CDT Mon Mar 15 2021

Areas affected...Eastern Kansas and much of central Missouri

Concerning...Severe potential...Watch unlikely 

Valid 151949Z - 152145Z

Probability of Watch Issuance...20 percent

SUMMARY...Strong to isolated severe storms are possible this
afternoon. These storms may pose a threat for large hail, damaging
winds, and perhaps a tornado or two.

DISCUSSION...Boundary layer heating beneath very cold mid-level
temperatures has destabilized portions of eastern Kansas and western
Missouri where MLCAPE is now around 200 to 300 J/kg per SPC
mesoanalysis. Expect further destabilization to around 500 J/kg and
expect it to expand eastward across Missouri as mid-level
temperatures cool. Expect storms to form in the next 1-2 hours in an
area of convergence along the surface trough which extends from near
Topeka, KS to Springfield, MO at 19Z, as it lifts northeastward.
Moderate to strong effective shear (around 35 to 40 knots per KSGF
VWP) will aid with storm organization through the afternoon. The
limited instability will be the primary detriment for stronger
storms, but a few severe storms are possible, especially across
central and eastern Missouri where instability and shear are both
expected to be maximized. The expanding area of cumulus/weak radar
returns northeast of Springfield, MO is likely where the strongest
storm or two will develop. 

Steep mid-level lapse rates and cold mid-level temperatures combined
with a favorable shear profile for supercells will support a threat
for large hail with the stronger storms. In addition, some damaging
winds may be possible given the well-mixed sub-cloud layer. 

A landspout tornado or two cannot be ruled out in close proximity to
the surface/mid-level low, mostly across eastern Kansas, where lapse
rates are steep and low-level vorticity is maximized. In addition, a
separate area with a supercell tornado threat will exist in central
and eastern Missouri. Low-level backed flow north and east of this
boundary is leading to effective SRH around 100 to 125 m2/s2 which
may increase to near 200 m2/s2 though the afternoon. In addition,
ingestion of low-level vorticity along the boundary may increase the
tornado threat. However, storm motion in relation to the orientation
of this boundary does call into question whether these storms will
be surface based or if they will be slightly elevated on the
cool-side of the boundary. 

Overall, the limited instability and resultant marginal threat may
preclude watch issuance. However, a locally favorable environment,
especially in central Missouri, will continue to be monitored.

..Bentley/Grams.. 03/15/2021

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

ATTN...WFO...LSX...SGF...EAX...TOP...ICT...

LAT...LON   37929545 38089585 38529607 39079604 39599583 39719524
            39729399 39519223 39389126 39069046 38749025 38309015
            37649052 37349160 37279279 37669333 37879399 37919470
            37909521 37929545

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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.