SPC Jul 4, 2025 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0758 PM CDT Thu Jul 03 2025

Valid 040100Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...

...SUMMARY...
Scattered severe thunderstorms capable of producing severe/damaging
winds and large hail are forecast across parts of the northern
Plains this evening into the early overnight hours.

...Northern Plains into the Upper Midwest...
Minimal changes have been made to severe probabilities across the
northern Plains. Even with large-scale upper ridging remaining
prominent over much of the central/northern Plains, ascent
associated with a weak mid-level shortwave trough over WY and
eastern MT should continue to encourage gradual convective
development this evening from northeast WY into ND. A surface lee
trough over eastern MT/western ND should also severe as a focus for
thunderstorms based on recent visible satellite/radar trends. A
moderately to strongly unstable airmass is present across much of ND
this evening, along with around 30-40 kt of deep-layer shear. This
favorable environment should support supercells with a large to
isolated very large hail threat initially (up to 1.5-2.5 inches in
diameter). There still appears to be some potential for a small but
organized bowing cluster to develop later this evening as convection
spreads into central/eastern ND in the presence of a strengthening
low-level jet. If this upscale growth can occur, then severe winds
with peak gusts up to 65-75 mph appear possible.

On the eastern periphery of the upper ridge, a separate area of
convection has developed across northeast IA and vicinity. This
activity may continue to pose an isolated severe hail/wind threat in
the short term given an unstable airmass with moderate instability
and modest deep-layer shear present. The longevity of this
convection still remains somewhat questionable given warm
temperatures and weak forcing aloft. Additional, mainly elevated
thunderstorms may also develop later this evening/overnight in an
arcing band across parts of MN into WI in association with
increasing low-level warm/moist advection. These thunderstorms may
pose some severe hail/wind threat given ample MUCAPE and the
presence of modestly steepened mid-level lapse rates. But, the
overall severe threat should tend to remain fairly isolated.

...Northeast...
Strong to severe thunderstorms across the Northeast have generally
moved offshore and/or weakened this evening. The potential for
organized severe thunderstorms has mostly diminished, but occasional
strong to damaging gusts may continue for another hour or two across
parts of far southeast PA into central/southern NJ, and separately
across far eastern MA and vicinity.

..Gleason.. 07/04/2025

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