430
ACUS03 KWNS 011935
SWODY3
SPC AC 011934

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 PM CDT Tue Jul 01 2025

Valid 031200Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN HIGH PLAINS...UPPER MIDWEST INTO THE GREAT LAKES...AND THE
NORTHEAST...

...SUMMARY...
Scattered storms capable of large hail and severe wind gusts are
forecast across the Northeast on Thursday. Isolated severe wind
gusts are also possible in the Northern Plains and parts of the
Upper Midwest into the Great Lakes.

...Synopsis...
A mid-level trough will deepen over New England as an upper trough
moves over the Midwest, and broad mid-level troughing with multiple
embedded impulses, overspreads the U.S. west of the Rockies on
Thursday. The East and West Coast upper troughs will encourage
surface troughing across the Northeast and the Plains states, as
well as weak surface low development over the Great Basin. Given the
presence of seasonal low-level moisture, and expected diurnal
heating, at least scattered thunderstorms will develop across much
of the Interior West, into the Plains, Midwest, and East Coast
regions. At least isolated strong to potentially severe storms could
develop over parts of the northern CONUS, where appreciable vertical
wind shear will overspread the warm, moist airmass to support
organized thunderstorms.

...Northeast...
As the surface trough progresses across the Northeast, deep-layer
northwesterly flow will overspread the region. Diurnal heating of a
seasonably moist boundary layer will foster modest buoyancy, with
500-1500 J/kg MLCAPE expected. As thunderstorms develop during the
afternoon, they will encounter roughly 25-35 kts of effective bulk
shear, characterized by elongated/straight hodographs. Multicells
and short line segments should be the main storm modes, with
isolated damaging gusts the primary threat with the stronger storms.


...Upper Midwest into the Great Lakes...
A belt of 35-45 kt northwesterly flow on the back side of the East
Coast upper trough will overspread the Great Lakes during the
afternoon hours, where diurnal heating of a moist low-level airmass
will destabilize the boundary layer. MLCAPE may exceed 2000 J/kg in
spots (locally higher to 3000 J/kg toward southeast MN given 7.5+
C/km mid-level lapse rates farther to the west). Forecast soundings
depict modestly curved and elongated hodographs, supporting
multicells and perhaps supercells with some of the stronger storms.
Isolated severe wind and hail may accompany the stronger storms.
Greater severe probabilities may be needed in future outlooks if
favorable trends in greater storm coverage are realized in later
available guidance.

...Northern High Plains...
A mid-level impulse will traverse the broader western upper
troughing regime and eject into the northern High Plains Thursday
afternoon. By this time, steep mid-level lapse rates will overspread
upper 60s F dewpoints to promote moderate to locally strong
instability, with MLCAPE exceeding 3000 J/kg. Modest turning and
strengthening of the winds with height will support elongated
hodographs with slight low-level curvature, which will support
multicells and splitting supercells given the aforementioned
buoyancy. The storms are forecast to be isolated in coverage, with a
few instances of severe wind and hail expected.

..Squitieri.. 07/01/2025

$$