Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Sun Aug 02 2026
Valid 021200Z - 031200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AD EVENING ACROSS THE LOWER GREAT LAKES/UPPER OHIO VALLEY INTO
MIDDLE AND SOUTHERN ATLANTIC SEABOARD...AND TONIGHT ACROSS PARTS OF
THE NORTHERN GREAT PLAINS...
...SUMMARY...
Scattered strong thunderstorm development is likely this afternoon
and evening across parts of the lower Great Lakes and upper Ohio
Valley into the middle and southern Atlantic Piedmont. This may be
accompanied by some risk for severe weather, mainly in the form of
localized damaging wind gusts.
...Discussion...
Models indicate that one notable short wave perturbation within the
westerlies will progress east of the Canadian Rockies through much
of the Canadian Prairies by early Monday. As this occurs, it
appears that an associated surface cyclone will occlude over
northern portions of the Prairies during the day today, with one
trailing cold front advancing east of the northern U.S. Rockies
before stalling/weakening across the adjacent high plains, as
another more substantive cold front approaches the western through
central Canadian/U.S. border.
At the same time, a trailing mid-level short wave trough is forecast
to dig inland of the Pacific Northwest, then turn eastward across
the northern U.S. intermountain region into Rockies. As it does, it
appears that it will contribute to at least some suppression of
initially more prominent mid-level ridging centered over the
Southwest.
Downstream, larger-scale mid-level troughing is likely to be
maintained east of the Mississippi Valley through the Atlantic
Seaboard. However, the most prominent embedded short wave trough
already appears to be in the process of becoming increasingly
sheared across the lower Ohio Valley. This is forecast to continue
while shifting eastward toward the Appalachians today through
tonight, with perhaps one emerging perturbation consolidating with
another digging impulse across the lower Great Lakes vicinity later
today through tonight. This may be accompanied by a northeastward
migrating surface low, trailed by a weak cold frontal slowly
advancing into and across the Appalachians.
...Eastern U.S...
To the east of the larger-scale mid-level trough axis, early day
cloud cover, precipitation, and otherwise generally weak
lower/mid-tropospheric lapse rates will probably tend to at least
slow, if not inhibit, boundary-layer destabilization. However,
convection-allowing guidance suggests that breaks in cloud cover
will eventually allow for widely scattered to scattered intensifying
thunderstorm development by late this afternoon, if not earlier.
It appears that this may tend to focus within a pre-cold frontal
corridor across the Allegheny Plateau/upper Ohio Valley into lower
Great Lakes vicinity, where it could be enhanced by 20-40 kt
south-southwesterly flow in the 850-500 mb layer, and within
somewhat more modest flow off the higher terrain into lee surface
troughing across the Piedmont. Given at least modest CAPE in excess
of 1000 J/kg, and potential for heavy precipitation loading in the
presence of seasonably high moisture content, localized strong
downbursts may generate a few damaging surface gusts.
Within the better shear across the Allegheny Plateau into lower
Great Lakes vicinity, the evolution of transient supercell
structures accompanied by some risk for a tornado does not appear
entirely out of the question, given forecast surface dew points
near/above 70F. However, this potential remains unclear, based on
varied model guidance.
...North Dakota...
Some model output suggests that there may be at least attempts at
deep convective development late this afternoon near the weak
pre-cold frontal surface troughing. However, the potential for
sustained thunderstorm activity remains more unclear due to limited
low-level moisture beneath very warm and dry mid-levels, associated
with an elevated mixed-layer overspreading the region during the
day. It appears that somewhat better potential for thunderstorm
development may await increasing forcing for ascent with the
approach of the upstream short wave trough by late tonight. Based
on forecast soundings this probably will be elevated or high-based
in nature, but perhaps accompanied by some risk for hail and/or
gusty winds.
..Kerr/Chalmers.. 08/02/2026
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TTq4Pb
