183
ACUS01 KWNS 161629
SWODY1
SPC AC 161627

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Wed Jul 16 2025

Valid 161630Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST AND CENTRAL HIGH PLAINS...

...SUMMARY...
Scattered severe thunderstorms are possible this afternoon and
evening over parts of the Midwest and central High Plains.

...Midwest/Great Lakes...
Late morning radar/satellite imagery shows an MCV over northeast IA
co-located with a 1007-mb surface low.  A front is draped from
northeast to southwest and is forecast to gradually push eastward
during the day.  The frontal segment east-northeast of the low will
remain quasi-stationary and serve as the northern delimiter of a
surface-based warm sector.  Continued heating of a moist boundary
layer will contribute to 1000-2500 J/kg of MLCAPE across central WI
into northern/central IL. The modestly enhanced low/mid-level
winds associated with the MCV will yield 30-40 kt of effective
shear---supporting rotation with a few of the stronger updrafts this
afternoon.

Semi-discrete thunderstorms developing in a north-south band will
likely continue to intensify as ascent overspreads the warm sector
over WI and far northern IL.  A few supercells are possible with an
attendant risk for all hazards.  With time late this afternoon
and evening, gradual upscale growth into a bowing cluster should
occur, with a greater risk for severe/damaging winds towards Lake
Michigan and parts of southern Lower MI.

...Central High Plains to Northern Missouri...
Indications late this morning are that a convectively reinforced
surface front will become stationary across KS into eastern CO with
moist, upslope flow into the central High Plains north of the
boundary.  The southern periphery of stronger mid-level westerly
flow will glance the central High Plains where strongly veering flow
will result in deep-layer shear supporting storm organization.
Although heating will be partially thwarted by persistent low-level
cloud cover through at least the early afternoon, sufficient heating
is expected to result in scattered to widespread thunderstorms
eventually developing during the late afternoon.  A few supercells
are possible with an accompanying threat for large hail and
localized severe gusts.  As storm coverage increases, upscale growth
into an organized cluster is probable during the evening.  Severe
gusts will likely become the primary hazard during the evening as
the mode becomes more linear and outflow dominant.

Farther east across KS into northern MO, isolated convection may
develop through peak afternoon heating along the front. While
deep-layer shear is forecast to remain fairly modest, strong
instability and steep mid-level lapse rates could still support
occasional severe hail/wind with the more robust cores that can be
sustained. Additional convection may develop along/north of the
front this evening in a low-level warm advection regime, while also
posing an isolated severe threat.

...Ohio Valley/Mid-Atlantic...
A couple of MCVs will focus scattered strong to locally severe
thunderstorms mainly this afternoon and early evening.  Relatively
weak lapse rates and modest deep-layer shear will tend to limit
storm organization.  Nonetheless, sporadic and isolated bouts of
strong to damaging gusts are possible with the stronger
thunderstorms through early evening.

...Central Gulf Coast...
Modest strengthening of the low-level wind field is expected as a
weak tropical disturbance migrates westward over the northern Gulf
of America.  However, model guidance shows hodographs generally
remaining diminutive in size, implying disorganized storm modes
(mainly outflow dominant structures in the form of bands and small
clusters).

..Smith/Lyons.. 07/16/2025

$$