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000
ACUS11 KWNS 262156
SWOMCD
SPC MCD 262155
ILZ000-WIZ000-IAZ000-MOZ000-262300-

Mesoscale Discussion 1423
NWS Storm Prediction Center Norman OK
0455 PM CDT Wed Jul 26 2017

Areas affected...Northern and central Illinois...far eastern Iowa

Concerning...Severe potential...Watch unlikely

Valid 262155Z - 262300Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms have exhibited somewhat greater organization and
intensity intensity over the past hour or so.  A WW issuance is not
currently anticipated, although damaging wind gusts may occur as
this line propagates through the discussion area over the next few
hours.

DISCUSSION...A north-to-south broken line of storms has organized
and increased in intensity over the past hour or so from near CID
southward to near UIN, with more isolated convection occurring
farther south into far northeastern Missouri.  A 48-knot wind gust
was reported near UIN with this activity in the past half hour.
These storms are in a strongly unstable environment (around 3000 to
4000 J/kg MUCAPE within the pre-convective airmass - highest in
central Illinois) and deep shear (around 30-40 knots) favoring at
least modest storm organization.  These storms are beginning to
propagate eastward at around 20-25 knots (especially across far
eastern Iowa) and an isolated damaging wind threat should exist
given the magnitude of downstream instability.

Recent high-resolution guidance suggests that storms may propagate
southeastward into central Illinois in the evening, which seems
reasonable given the orientation of the moist axis and location of
maximum instability.  Convective trends will be monitored, although
a WW issuance is unlikely at this time.

..Cook.. 07/26/2017

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

ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...

LAT...LON   42229123 42529067 42518942 42058838 41178793 40238802
            39668846 39308959 39279071 39429113 40179116 40919128
            41969128 42229123

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