575
ACUS02 KWNS 150529
SWODY2
SPC AC 150527

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Tue Jul 15 2025

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN...

...SUMMARY...
Scattered strong to severe thunderstorms are possible Wednesday
afternoon and evening from parts of the central High Plains to the
Great Lakes.

...Mid-MS Valley/Great Lakes Vicinity...

An upper shortwave trough and MCV is forecast to be located over IA
Wednesday morning. Some ongoing convection is possible from MN into
IA associated with this feature and attendant outflow. As the MCV
shifts east/northeast, a composite outflow/surface cold front
located from central WI into eastern IA will develop eastward across
portion of northern MO/IL through the evening. The downstream warm
sector will be characterized rich moisture, with dewpoints in the
70s F. Daytime heating and modest lapse rates will support strong
instability (2000-3000 J/kg MLCAPE). Vertical shear should increase
as strengthening midlevel westerlies overspread the region,
resulting in 25-35 kt effective shear magnitudes. Organized cells
and clusters will pose a risk for damaging gusts. Low-level shear
may be somewhat enhanced close to the MCV/surface low across
northern IL. Forecast soundings show modestly enlarged/curved
hodographs and a tornado or two could also occur. A more marginal
severe risk could spread east into portions of Lower MI and northern
IN during the late evening/overnight hours, but overall risk should
gradually diminish with eastward extent.

...Central Plains Vicinity...

The western edge of a southward sagging cold front will move across
eastern CO/NE and portions of KS during the day. A very moist and
unstable airmass is expected across the region. Vertical shear will
remain modest, with stronger midlevel westerlies expected to lag
behind the front. Nevertheless, the sagging surface front should
provide focus for isolated to scattered thunderstorm development
within the warm sector, with an accompanying risk for strong gusts.

Additional storms are expected to develop over the central High
Plains of southeast WY/eastern CO in the post-frontal upslope
regime. This activity will spread eastward during the evening and
may be elevated. Isolated hail and strong gusts will be possible
initially. While guidance varies considerably, some potential exists
for an MCS to develop over parts of KS during the nighttime hours as
the front continues to sag southward and a modest low-level jet
develops. Given large model spread, will hold off on higher outlook
probabilities at this time.

...Upper Ohio Valley...

Scattered to numerous thunderstorms are expected across the region i
response to a shortwave impulse. While modest instability is
forecast amid a very moist airmass, vertical shear will remain weak.
Sporadic strong gusts/wet microbursts could occur, but organized
severe potential continues to be limited/uncertain.

..Leitman.. 07/15/2025

$$