Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sun Aug 24 2025
Valid 241200Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NEW YORK/PENNSYLVANIA AND FROM EASTERN COLORADO TO WESTERN
OKLAHOMA...
...SUMMARY...
A few storms may reach severe thresholds from eastern Colorado into
western Oklahoma this afternoon and evening. Scattered strong-severe
storms are possible across portions of Pennsylvania and New York.
Hail or wind are the expected risks.
...NY/PA...
Early-morning satellite imagery depicts a strong upper trough over
ON/Great Lakes, shifting east-southeast in line with latest model
guidance. Associated surface front is forecast to advance into
western NY/PA by early afternoon before shifting into central
portions of these states by 25/00z. Modest boundary-layer heating is
expected to aid destabilization ahead of the front and convective
temperatures are expected to be breached around 20-21z; although,
deep-layer lapse rates are not expected to be particularly steep
(0-6km values around 6.5 C/km). While CAMs support this with
scattered frontal convection developing around mid afternoon. This
activity could generate locally strong winds, and perhaps some hail.
Main risk will be during the mid afternoon into early evening before
the boundary layer cools after sunset.
...Eastern CO to western OK...
Eastern periphery of Great Basin high will flatten as northwesterly
flow becomes firmly established along the back side of Great
Lakes/OH Valley trough. At the surface, pronounced surface
anticyclone will settle into the northern Plains, ultimately forcing
the leading edge of more continental air into the southern Plains by
the end of the period. Net take is a corridor of low-level warm
advection will become established from southern WY into western OK -
coincident with northwest-southeast frontal orientation. It appears
a few weak disturbances will top the ridge and dig southeast toward
the southern Plains. Each of these features should encourage a
response in the LLJ, which will aid convective development. Elevated
convection may be ongoing at the start of the period across western
NE into northwest KS. A substantial cluster/MCS should propagate
southeast with renewed development later in the period. Rain-cooled
boundary layer will ensure stronger heating is focused across
southeast CO into western OK. Primary concern for isolated severe
will be near this zone of stronger heating/instability. Hail and
wind may accompany this more robust convection.
..Darrow/Weinman.. 08/24/2025
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