Mesoscale Discussion 1242

Issued

Jul 10, 2021, 3:09 PM CDT (20:09 UTC)

Expired

Jul 10, 2021, 4:45 PM CDT

In force

96 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Cass County, IL, Champaign County, IL, DeWitt County, IL, Douglas County, IL, Ford County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Moultrie County, IL, Piatt County, IL, Sangamon County, IL, Tazewell County, IL

The Lincoln radar (KILX), 10 km from the middle of the area, began a volume at 20:13 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.

509 
ACUS11 KWNS 102009
SWOMCD
SPC MCD 102009 
ILZ000-102145-

Mesoscale Discussion 1242
NWS Storm Prediction Center Norman OK
0309 PM CDT Sat Jul 10 2021

Areas affected...central Illinois

Concerning...Severe potential...Watch unlikely 

Valid 102009Z - 102145Z

Probability of Watch Issuance...20 percent

SUMMARY...An additional brief tornado or two remains possible with
the longer lasting, more dominant updrafts over the next couple of
hours. The very brief, localized nature of the severe threat
precludes a WW issuance at this time, though trends will continue to
be monitored.

DISCUSSION...An MCV has recently developed across west-central IL in
association with the remnants of an older MCS that has propagated
out of MO earlier this morning. A few discrete supercells have
developed in close proximity to the MCV center, including a
relatively more dominant supercell with a history of brief tornadoes
over the past 1-2 hours. Ahead of the MCV cluster, locally backed
surface winds have been noted, which are likely locally enhancing
low-level shear, with nearly 200 m2/s2 0-3km SRH, as shown by the
1918Z KILX VWP. 

Nonetheless, buoyancy is quite scant, with well under 500 J/kg
MLCAPE present ahead of the MCV. In addition, precipitation and
clouds ahead of the MCV will continue to hinder more robust surface
heating and subsequent instability from manifesting. As such, the
tornado threat is expected to remain relatively limited overall,
with a brief tornado or two likely with the most dominant storms. A
WW issuance is not anticipated, though trends will continued to be
monitored for an increase in the tornado threat.

..Squitieri/Bunting.. 07/10/2021

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

ATTN...WFO...LOT...ILX...

LAT...LON   40289035 40518997 40738922 40798861 40568797 40208779
            39798798 39638858 39698947 39808999 39859036 40289035

Mesoscale 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.