MD 0113 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PARTS OF NORTHERN IL INTO EXTREME EASTERN IA/SOUTHERN WI
Mesoscale Discussion 0113
NWS Storm Prediction Center Norman OK
0253 PM CST Thu Feb 08 2024
Areas affected…Parts of northern IL into extreme eastern
IA/southern WI
Concerning…Severe potential…Watch unlikely
Valid 082053Z – 082330Z
Probability of Watch Issuance…20 percent
SUMMARY…A supercell or two may develop later this afternoon. Large
hail, gusty winds, and possibly a tornado will all be possible,
though coverage of the threat is expected to remain isolated.
DISCUSSION…Convection is gradually deepening within a cumulus
field this afternoon from eastern IA/northeast MO into western IL,
in advance of a mid/upper-level trough approaching the upper MS
Valley. Low-level moisture remains rather modest across the region,
with surface dewpoints generally in the mid/upper 40s F. However,
seasonably strong diurnal heating beneath cold temperatures aloft is
supporting MLCAPE of around 500 J/kg, along with diminishing MLCINH.
Destabilization should spread into a larger portion of northern IL
and southern WI through late afternoon, in conjunction with eastward
progression of the midlevel cold pool.
The primary midlevel vorticity maximum and attendant surface cyclone
are moving northeastward across MN, and large-scale ascent may
remain rather modest across the effective warm sector. However, a
low-amplitude shortwave is moving through the base of the
mid/upper-level trough near the IA/MO border, and may aid in
thunderstorm development as any remaining convective inhibition is
removed.
Strong deep-layer shear across the region will conditionally support
organized convection, and a supercell or two may eventually evolve
out of initial storm development. Steep tropospheric lapse rates
will support large hail and locally gusty winds with the strongest
storms. Also, despite less than ideal low-level moisture, a tornado
cannot be ruled out given the presence of favorable low-level shear
and lapse rates. At this time, coverage of the severe threat is
expected to remain rather isolated.
..Dean/Goss.. 02/08/2024
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…LOT…ILX…MKX…DVN…ARX…
LAT…LON 42549087 42829082 43078992 42928936 42378892 41368878
40758891 40618938 40569005 40959076 41299078 42549087
