Latest update on Severe Thunderstorm Watch #651 as storms move east across northern Illinois and southern Wisconsin
Mesoscale Discussion 1971
NWS Storm Prediction Center Norman OK
1058 PM CDT Thu Sep 12 2019
Areas affected...northern Illinois into southern Wisconsin
Concerning...Severe Thunderstorm Watch 651...
Valid 130358Z - 130600Z
The severe weather threat for Severe Thunderstorm Watch 651
SUMMARY...A few strong to severe wind gusts remain possible mainly
over northern Illinois.
DISCUSSION...A line of storms has gradually consolidated along the
cold front over northwest IL, while a leading elevated line of
storms continues into southeast WI. Cool surface temperatures north
of the warm front have mitigated wind potential over WI, but
southerly winds are aiding warming temperatures over parts of
The stronger winds aloft are mainly along and west of the cold
front, with deep-layer shear roughly parallel to the front.
Low-level shear is generally decreasing due to veering 850 mb winds,
but mean winds through a deep layer as well as around 1500 J/kg
MLCAPE may support periodic strengthening. A few damaging wind gusts
remain possible, as well as marginal hail. Additional watches appear
unlikely at this time unless further strengthening occurs.