LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0720 AM CDT Sun Aug 17 2025
Valid 171300Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN
NEW ENGLAND....
...SUMMARY...
One or two clusters of thunderstorms may develop and gradually pose
a risk for damaging wind gusts from the northern High Plains into
the Midwest this afternoon and tonight. Damaging thunderstorm wind
gusts may also occur across parts of the northern Mid Atlantic into
southern New England late this afternoon and evening.
...Northern Plains into Upper Midwest...
A broad upper ridge remains in place over southern/central U.S
today. Several weak perturbations will top the ridge during this
forecast period, affecting much of the northern Plains and upper
Midwest. Each of these smaller-scale shortwave troughs will
potentially be associated with a cluster of thunderstorms.
Sufficient low-level moisture and 25-35 knots of westerly flow aloft
pose some conditional risk of severe storms throughout this region,
but considerable uncertainty on the timing and placement of
convection precludes upgrading any areas to SLGT at this time.
Multiple areas of ongoing convection this morning further complicate
the forecast. Perhaps by 1630z, areas of stronger daytime
heating/destabilization will allow better focus of the severe
outlook.
...Mid Atlantic into southern New England...
A cold front currently extends from OH northeastward into the St.
Lawrence Valley. Forecast soundings ahead of the front show weak
mid-level lapse rates and limited mid-level dry air. However,
strong heating into the 80s and 90s F, coupled with dewpoints near
70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow
aloft and frontal forcing may be sufficient for isolated strong
storms capable of locally gusty/damaging winds this afternoon.
..Hart/Dean.. 08/17/2025
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TMXLKW
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)
Sunday, August 17, 2025
SPC Aug 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)