LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Sat Oct 04 2025
Valid 041200Z - 051200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
ROCKIES INTO THE NORTHERN PLAINS...
...SUMMARY...
Isolated severe wind gusts/hail may accompany the stronger
thunderstorms across the central Rockies into the northern High
Plains late this afternoon and evening.
...Central Rockies to northern Plains...
Upper low over southern NV will begin to eject northeast over the
next few hours, advancing into UT by 12z then open up as a
progressive short-wave trough over WY/CO by early evening. This
feature will move into the eastern Dakotas overnight as 500mb speed
max intensifies and translates toward the upper Red River Valley by
05/12z. At the surface, synoptic front is expected to move very
little, extending from southeast MB-eastern ND-southeast WY.
While strong boundary-layer heating is forecast across the high
Plains into southeast SD, instability should remain weak despite
steep 0-3km lapse rates. Isolated thunderstorms should develop ahead
of the short wave across southeast WY/NE Panhandle into western SD,
but forecast soundings suggest hail will struggle to be more than
marginally severe. Some gust potential exists where lapse rates are
steep. More concentrated robust updrafts are expected along the cool
side of the boundary from northern SD into eastern ND/northwest MN
during the latter half of the period. Forecast soundings suggest the
most buoyant parcels will be rooted near 850mb where MUCAPE could
exceed 1500 J/kg. This post-frontal convection will be aided by a
strengthening LLJ which should encourage some organization,
especially given the approaching short wave. This activity will be
focused mostly after sunset and hail could exceed 1 inch in the
strongest elevated updrafts.
..Darrow/Lyons.. 10/04/2025
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TNSpHj
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)
Saturday, October 4, 2025
SPC Oct 4, 2025 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)




















