210
ACUS01 KWNS 010604
SWODY1
SPC AC 010603

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0103 AM CDT Tue Sep 01 2026

Valid 011200Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL/NORTHERN PLAINS AND MIDWEST INTO PARTS OF PENNSYLVANIA
NEW YORK AND NEW JERSEY....

...SUMMARY...
Scattered strong to severe storms are possible over the central
Plains and Midwest, as well as parts of New York, Pennsylvania and
New Jersey.

...Eastern Great Lakes, OH valley and NY/NJ...
Scattered showers and thunderstorms are expected to be ongoing early
in the period across parts of NY associated with a lead shortwave
trough and warm advection. Remnant clouds, showers and storms should
persist trough the day along a northwest to southeast warm front
across northern/eastern NY into NJ. A second shortwave trough and
mid-level jet will approach during the afternoon providing ascent
across the upper OH Valley and NY.

Despite modest mid-level lapse rates, 70s F surface dewpoints and
strong heating will support a very unstable air mass with MLCAPE of
3000+ J/kg south of the warm front. Increasing vertical shear ahead
of the mid-level speed max will favor a mix of supercells and line
segments across southern NY, PA and NJ through the afternoon.
Scattered damaging gusts and isolated hail are the most likely
hazards. Low-level shear will be greatest near the southern Hudson
Valley and the instability gradient into northeast PA/northern NJ.
Enhanced ESRH could support a couple of tornadoes with the stronger
supercells or QLCS segments.

Some guidance shows additional thunderstorms developing over
southern lower MI and ON early Wed, associated with another
mid-level wave speed max across the eastern Great Lakes. Sufficient
elevated buoyancy (2000 J/kg MUCAPE) and vertical shear will exist
for some damaging wind threat should this occur. This scenario
remains uncertain, but these storms could potentially track
southeast and organize, approaching northeast OH and western NY/PA
by 12z Wed morning.

...Central/northern Plains...
A stalled front will lift northward across parts of NE/SD as several
low-amplitude shortwave troughs move out of the Rockies and onto the
Plains. Weak ascent from these features will modestly deepen a
surface low across NE and SD. In response, strengthening southerly
flow/moisture should result in moderate to strong destabilization by
early afternoon.

Convection lingering from overnight may begin to rejuvenate along
and north of the front across SD as heating increases through the
afternoon. Meanwhile, inhibition owing to warm mid-level
temperatures will likely remain in place most of the day south of
the front. Weak ascent and strong heating should be sufficient to
support isolated storm development by late afternoon. A belt of
enhanced southwesterly flow aloft would favor organization with
supercell or strong clusters likely. Hail (some 2+ inch) is possible
along with damaging gusts given a supercell mode. A tornado or two
is also possible given the potential for supercells to reside along
the boundary where low-level flow will be substantially backed and
hodographs expanded.

Eventually, one or more clusters may merge into an MCS and track
eastward along the front into eastern SD and southern MN through the
evening. Damaging gusts will be possible if this convection can
organize through the late evening/overnight hours. Model guidance
varies on the intensity and organization of the system. However,
confidence has increased enough that 15% CIG1 wind probabilities
have been added along the front.

...High Plains...
To the southwest along the surface lee trough, high-based convection
is likely to develop around peak heating across southwestern NE into
eastern Co and western KS. Despite more limited surface moisture,
very warm temperatures and steep lapse rates in the lower/middle
troposphere will promote strong multicell clusters. These storms
could produce severe gusts as they move east/northwest eventually
moving into more unstable air.

...Upper TX Coast...
TS Eduardo located near 28.6N 91.8W as of 10 pm CDT is forecast to
move toward the southwest LA/southeast TX coast and make landfall
tonight. Wind fields are forecast to remain relatively confined
given its small size and fast westward motion. This should limit
stronger low-level shear favorable for supercells and tornadoes.

..Lyons/Wendt.. 09/01/2026

$$