LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Wed Aug 26 2026
Valid 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
CENTRAL HIGH PLAINS...OZARKS/MID-SOUTH...AND MIDWEST...
...SUMMARY...
Isolated to widely scattered severe storms are expected across parts
of the central and southern High Plains, Great Lakes into the Ohio
Valley, and parts of the Ozarks to Lower Mississippi Valley.
Damaging/severe gusts are the main threat across these regions,
though large hail is also possible, particularly across the High
Plains.
...Lower MI into parts of northwest OH...IN/IL...Eastern MO...
A mid/upper trough will move from the Upper Great Lakes/Midwest
toward the Lower Great Lakes/Ohio Valley through the period. A
surface low will move across Ontario, as a trailing cold front moves
across parts of the Great Lakes and Ohio/mid MS Valleys. Moderate to
locally strong destabilization is generally expected along/ahead of
the front from parts of MO/IL/IN into lower MI, though early-day
convection and cloudiness could limit heating/destabilization with
northward extent. Scattered storm development is expected along the
front during the afternoon, which will spread east-southeastward
into the early evening.
Effective shear of generally 30-40 kt will support some storm
organization, with a few supercells and/or organized line segments
possible. Damaging winds and large hail could accompany the
strongest storms. If any supercells can be sustained, then some
tornado potential cannot be ruled out, especially from northern IN
into parts of lower MI, where some enhancement to low-level
shear/SRH is currently forecast.
...Parts of the Ozarks into the Lower MS Valley...
Guidance varies regarding potential for morning convection across
southeast MO. If substantial early-day convection does develop, then
a loosely organized cluster could evolve and move southeastward into
parts of western TN and northern MS/AL, with wind-damage potential.
Otherwise, scattered storm development is expected from southern MO
into AR and eastern OK by late afternoon, potentially aided by an
MCV that may emerge from parts of the southern Plains. Deep-layer
shear will be marginally supportive of storm organization, and
relatively large PW and buoyancy will support potential for
downbursts and loosely organized clusters with a wind-damage threat.
Isolated hail also cannot be ruled out with the strongest updrafts.
Some guidance depicts maintenance of a southward-moving storm
cluster into late tonight, resulting in some wind-damage potential
spreading into parts of southern LA/MS before the end of the period.
...Central/southern High Plains...
Across the central High Plains, relatively moist low-level easterly
flow and diurnal heating will result in moderate destabilization
this afternoon. Scattered storm development is expected by late
afternoon, with sufficient effective shear within the northwesterly
flow regime for organized multicells and possibly a few supercells.
Large hail (potentially approaching 2 inches in diameter) and
localized severe gusts will be the primary threats. Some
clustering/upscale growth is possible during the evening, which
could result in maintenance of a severe-wind threat into parts of
western KS.
For the southern High Plains, deep-layer shear will generally be
weaker compared to areas farther north, with relatively disorganized
convection expected. However, storm development within a very warm
and well-mixed environment will support potential for at least
localized severe gusts as convection spreads from eastern NM into
the TX/OK Panhandles. Depending on trends regarding storm coverage
and clustering within this regime, greater wind probabilities may
eventually be needed.
..Dean/Weinman.. 08/26/2026
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TV9rCr
Windy.com Temps | Gusts | WU KORD KPWK |
CLICK for this month's BIG night sky ... | RADAR FULL MAP SCREEN |
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MOBILE DEVICE? Turn sideways. Weather conditions directly above are near Lakefront. Top tabs refer to O'Hare (official).
Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.
CONVECTIVE | TORNADO | WIND | HAIL
O'Hare International Airport KORD
(Arlington Heights South)
Chicago Executive Airport KPWK
(Arlington Heights North)
Wednesday, August 26, 2026
SPC Aug 26, 2026 0600 UTC Day 1 Convective Outlook
SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)




















