ACUS03 KWNS 040728
SWODY3
SPC AC 040727

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 AM CDT Thu Jun 04 2026

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS FAR
SOUTHEAST LOWER MICHIGAN...NORTHERN AND CENTRAL OHIO...WESTERN
PENNSYLVANIA...FAR WESTERN NEW YORK...NORTHEAST MONTANA...AND
WESTERN NORTH DAKOTA...

...SUMMARY...
Scattered severe storms capable of large hail and damaging winds are
possible from portions of the Great Lakes and Ohio Valley into the
Northeast, and over the northern High Plains.

...Synopsis...

A short-wave trough and attending belt of 40-50 kt mid-level winds
initially over the Great Lakes will overspread the Northeast and
Mid-Atlantic Saturday into Saturday night. Meanwhile, an intense
upstream trough is forecast to move through the Canadian Rockies and
Pacific Northwest into the northern Rockies, with downstream height
falls and strengthening mid/upper-level winds advancing into the
northern High Plains.  Elsewhere, a mid-level low initially centered
along the NM-TX state line is expected to evolve into an open wave
while lifting northeast across the central and southern Plains.

At the surface, a cold front will push through the Great Lakes, New
England, and OH Valley during the forecast period, while a lee
cyclone deepens along a cold front moving through the northern High Plains.

...Great Lakes and OH Valley into the Northeast...

A westerly low-level jet will advect an increasingly moist air mass
through the Great Lakes and OH Valley into the Northeast ahead of
the cold front on Saturday. The moisture increase will combine with
daytime heating to support a moderately unstable environment across
the OH Valley, with instability diminishing with northeastward
extent into New England. Thunderstorms are expected to increase in
coverage and intensity through the afternoon ahead of the short-wave
trough, and amidst a kinematic environment featuring 30-40 kt of
deep-layer shear. The most favorable overlap of stronger
instability, vertical shear, and forcing for ascent is expected to
materialize across the upper OH Valley Saturday afternoon, where
supercells will be possible with a higher-probability risk for large
hail and damaging winds. Elsewhere, isolated occurrences of large
hail and/or damaging wind will be possible during the afternoon and
evening hours.

...Northern High Plains...

The presence of steep lapse rates and increasing boundary-layer
moisture content are expected to contribute to a moderate to
strongly unstable air mass by afternoon ahead of the surface low and
cold front over eastern MT and western ND. Moisture wrapping around
the surface low is expected to reach into the high terrain of
central MT, supporting at least modest destabilization there.
Initial, isolated storms are expected in the post-frontal, upslope
environment in central MT Saturday afternoon, with storms
potentially not developing until Saturday evening in the vicinity of
the front in eastern MT and western ND, due to late-arriving forcing
for ascent. Vertical shear will strengthen through the day with the
kinematic environment favoring supercell storm modes with the
primary hazard being large hail.

...Southern Plains....

The models indicate a band of 30-35 kt mid-level winds developing
within the southeast quadrant of the upper low from southwest TX
into the Red River Valley Saturday afternoon. As a result, vertical
shear will be enhanced in those areas; however, the primary
uncertainty regarding some severe-storm threat is the effect of
early-day storms on afternoon air mass destabilization.

..Mead.. 06/04/2026

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