Mesoscale Discussion 1035

Issued

Jun 20, 2021, 2:02 PM CDT (19:02 UTC)

Expired

Jun 20, 2021, 4:00 PM CDT

In force

118 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

40%

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• Severe Thunderstorm Watch 294Jun 20, 4:00 PM CDT

037 
ACUS11 KWNS 201903
SWOMCD
SPC MCD 201902 
MOZ000-IAZ000-KSZ000-NEZ000-202100-

Mesoscale Discussion 1035
NWS Storm Prediction Center Norman OK
0202 PM CDT Sun Jun 20 2021

Areas affected...Southern Iowa...northern Missouri...and northeast
Kansas

Concerning...Severe potential...Watch possible 

Valid 201902Z - 202100Z

Probability of Watch Issuance...40 percent

SUMMARY...Scattered strong to severe thunderstorms may develop along
a southeastward moving cold front by the mid afternoon hours. The
strongest storms may pose a severe hail and damaging wind risk. A
watch is possible.

DISCUSSION...Latest GOES visible imagery shows a growing field of
cumulus along the southern IA/NE border in the vicinity of a cold
front and nearby surface trough (with a shallower field noted along
the front stretching back to the southwest into northern KS). The
cumulus along the IA/NE border have taken on more agitated
characteristics with some vertical development noted in the past
30-60 minutes. Modified morning soundings, as well as RAP forecast
soundings and mesoanalysis estimates, suggest that MLCIN is waning
as temperatures climb into the upper 80s with upper 60s/low 70s
dewpoints. These trends suggests that convective initiation is
possible in the coming hours (likely by mid afternoon) - initially
within the IA/NE cumulus field and then possibly along the cold
front to the southwest. 

A favorable parameter space just ahead of the cold front (1000-2000
J/kg MLCAPE and 40-45 knots of effective bulk shear) should support
strong convection. Deep-layer flow oriented nearly orthogonal to the
cold front may support initially discrete to semi-discrete modes
that may pose a hail/wind threat. However, slightly cooler/stable
outflow from prior convection across northern MO/southern IA and
increasing inhibition southwestward into KS introduce some
uncertainty into the spatial extent of the threat. Air mass recovery
trends across northern MO/southern IA will continue to be monitored
and a watch is possible in the coming hours.

..Moore/Hart.. 06/20/2021

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

ATTN...WFO...LSX...DVN...DMX...EAX...OAX...TOP...

LAT...LON   38819335 38559437 38679510 39019568 39579599 40189580
            40449556 41339500 42119447 42039323 41669232 40549228
            39509243 38819335

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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.