LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sat Jul 26 2025
Valid 262000Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS AND MID-ATLANTIC...
...SUMMARY...
Severe thunderstorms accompanied by damaging wind gusts are possible
this afternoon through tonight in parts of the northern
Plains. Isolated strong to severe storms will also be possible from
the Ohio Valley and lower Great Lakes into the Mid-Atlantic region,
and across the central High Plains and much of Montana.
...20Z Update...
The forecast remains on track, and only minor changes were made with
this update. The Marginal risk was expanded slightly eastward in
northern MN, where an ongoing cluster of storms (preceding a remnant
MCV) may pose a risk of strong/severe gusts through the afternoon.
For details on the near-term severe risks in the Mid-Atlantic and
Midwest, reference MCDs 1790/1791.
..Weinman.. 07/26/2025
.PREV DISCUSSION... /ISSUED 1146 AM CDT Sat Jul 26 2025/
...Northern Plains...
Ahead of an upper low over northern California/western Nevada,
midday water vapor imagery reflects a lead shortwave trough moving
northeastward over northern Utah/eastern Idaho and western Wyoming.
In this regime, forcing for ascent and gradual cooling aloft will
occur through late today over northern Wyoming and southern/eastern
Montana. Northerly/upslope surface winds, combined with strong
heating and moderate CAPE values, will promote the development of
scattered high-based gusty thunderstorms by late afternoon. This
will initially occur across southern Montana and toward the Big
Horns/northeast Wyoming. Additional high-based storm development is
expected near the surface low and southward-extending surface trough
into the central High Plains. Storms that move into the western
Dakotas will encounter progressively higher CAPE and likely grow
upscale through the evening with a greater risk of organized severe
winds, aside from some continued hail potential. As least some
late-night severe risk will probably persist across North
Dakota/eastern South Dakota into Minnesota.
...Midwest to Mid-Atlantic States/Delmarva...
Multiple clusters of have persisted and/or reinvigorated early today
in a corridor spanning north-central Illinois/northern Indiana, as
well as central Pennsylvania. Moist/humid conditions will exist
south of the convectively reinforced boundary and away from areas of
persistent cloud debris (such as northward into Lower Michigan),
with a reservoir of ample buoyancy contributing to a diurnal
intensification of storms as multiple convectively enhanced
mid-level disturbances interface with the effective front and nearby
warm sector. The strongest storms will be capable of damaging winds,
and a somewhat more favorable corridor for severe thunderstorms/wind
damage appears to exist across the Mid-Atlantic States including
south/southeast parts of Pennsylvania toward the Delmarva/Chesapeake
Bay.
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