LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0655 AM CST Wed Dec 17 2025
Valid 171300Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHWEST AND NORTHERN INTERMOUNTAIN REGION...
...SUMMARY...
Sporadic severe wind gusts may accompany low-topped convection
across parts of the Northwest and northern Intermountain region this
morning into midday.
...Northwest/Northern Intermountain region...
A progressive/vigorous shortwave trough will continue to modestly
amplify and otherwise race east-southeastward from the
Washington/British Columbia border vicinity this morning to the
northern Plains tonight. Intense deep-tropospheric flow (highlighted
by 55-85 kt at 700 mb) will accompany this wave, yielding widespread
high winds across much of the Northwest to the northern Great
Plains.
Low-topped convection, occasionally capable of lightning and
semi-organized line segments, will continue in association with the
east/southeastward-advancing cold front, with convection potentially
expanding by late morning towards the Snake River Plain/Yellowstone
vicinity and potentially other parts of the northeast Great Basin by
afternoon. Surface-based instability will be very limited, but some
convectively enhanced wind gusts may occur.
..Guyer/Lyons.. 12/17/2025
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TPsjsL
Windy.com Temps | Gusts | WU KORD KPWK |
CLICK for this month's BIG night sky ... | RADAR FULL MAP SCREEN |
|---|
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, December 17, 2025
SPC Dec 17, 2025 1300 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)




















