Mesoscale Discussion 1888

Issued

Oct 24, 2021, 12:40 PM CDT (17:40 UTC)

Expired

Oct 24, 2021, 3:15 PM CDT

In force

3 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...tornado watch likely

Chance of a watch

95%

The Springfield radar (KSGF), 148 km from the middle of the area, began a volume at 17:43 UTC, the scan nearest the moment this went out.

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• Tornado Watch 531Oct 24, 2:05 PM CDT

112 
ACUS11 KWNS 241741
SWOMCD
SPC MCD 241740 
ILZ000-MOZ000-242015-

Mesoscale Discussion 1888
NWS Storm Prediction Center Norman OK
1240 PM CDT Sun Oct 24 2021

Areas affected...Much of MO and parts of west-central IL

Concerning...Severe potential...Tornado Watch likely 

Valid 241740Z - 242015Z

Probability of Watch Issuance...95 percent

SUMMARY...The threat for tornadoes, large hail, and severe wind
gusts will increase as storms develop and intensify this afternoon.
Tornado Watch issuance will be needed.

DISCUSSION...A low-amplitude shortwave trough will continue moving
eastward across the central Plains and MO Valley this afternoon.
Large-scale ascent preceding this feature is already supporting
isolated convection ahead of a cold front just east of the KS/MO
border. Latest surface observations show a warm front extends
eastward across MO. With a surface low progged to develop across
northern MO this afternoon, this warm front may lift northward a
little bit more across MO over the next few hours. Diurnal heating
of a moist low-level airmass across this region along with steep
mid-level lapse rates will likely support 1500-2000 J/kg of MLCAPE
by mid to late afternoon. A veering and strengthening wind profile
at both low and mid levels will foster 40-50 kt of effective bulk
shear, which is more than sufficient for supercells.

Current expectations are for surface-based storms to develop along
or just ahead of the cold front across western MO by 19-20Z (2-3 PM
CDT). Some short-term guidance suggests that other storms may
initiate across the open warm sector as well. Supercells will likely
be the dominant storm mode initially this afternoon, as sufficient
cross-boundary flow aloft is present along and ahead of the cold
front. Given the steep mid-level lapse rates present, large hail
should occur with these supercells. Low-level shear also appears
strong in recent VWPs from KEAX/KSGF. Effective SRH in the 200-300
m2/s2 range will likely foster low-level rotation and potential for
tornadoes with any supercells. The best low-level shear and related
tornado potential may exist along the warm front, where low-level
winds will be backed to a more east-southeasterly direction. A
couple of these tornadoes, especially across MO, could be strong
since the thermodynamic and kinematic environment both appear rather
favorable. With time, one or more broken lines of supercells and/or
small clusters are expected to advance eastward across MO and into
parts of west-central IL. The severe wind threat may eventually
increase, especially if storms develop more linear characteristics
versus a broken line of supercells. Regardless of eventual
convective evolution, the increasing severe threat this afternoon
will require Tornado Watch issuance within the next couple of hours
(likely by 2-3 PM CDT).

..Gleason/Thompson.. 10/24/2021

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

ATTN...WFO...LSX...SGF...EAX...

LAT...LON   39649093 39289040 38789001 37719066 36919151 36519239
            36519370 36559457 37019458 37639452 38939409 39839351
            39869273 39819162 39649093

Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Illinois, 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.