Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0713 AM CDT Thu Jul 03 2025
Valid 031300Z - 041200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTH DAKOTA
AND MUCH OF THE NORTHEAST...
...SUMMARY...
Scattered severe thunderstorms capable of producing severe/damaging
winds and large hail are forecast across parts of the Northeast and
northern Plains today.
...Northern Plains...
Water-vapor imagery this morning indicates a weak disturbance over
western ND is cresting a central U.S. upper ridge. An upstream
minor perturbation is forecast to move from northern WY/MT eastward
into western ND by late afternoon/evening. Coincident with this
feature, an elongated weak low is forecast from the north-central
High Plains northward into SK, with an attendant warm frontal zone
draped east-southeast from ND into the Upper Midwest.
A seasonably moist boundary layer is indicated by morning surface
observations. Dewpoints currently range from the lower 60s deg F
over ND to upper 60s to near 70 in central and eastern SD. Steep
700-500 mb lapse rates coupled with heating in wake of morning cloud
debris/shower activity, will likely result in a weakly capped and
very unstable airmass by mid-late afternoon over ND where low-level
moisture is maximized. Isolated to scattered storms are forecast to
develop 20-23 UTC with a few supercells possible. A risk for very
large hail and perhaps a tornado would accompany the supercells
before storm outflow and mergers leading to upscale growth into one
or two eastward-moving clusters during the evening. Have introduced
a significant wind highlight for potential peak gusts in the 70-85
mph range. A focused mesoscale wind corridor is indicated by some
00z HREF and MPAS members but sufficient model variability precludes
higher probabilities at this time. This activity will likely weaken
late this evening as it approaches the Red River and adjacent
portions of northern MN.
...Northeast...
An upper trough with an embedded 40-50 kt mid-level speed maximum
will pivot across the Northeast today. A related surface cold front
will likewise develop eastward across this region through the
afternoon/evening. Heating will act to destabilize a moist
airmass and support weak to moderate buoyancy (500-1500 J/kg MLCAPE)
along/ahead of the cold front by early afternoon. Sufficient
deep-layer shear will favor multicellular and some transient
supercell organization. Scattered damaging (50-65 mph) winds should
be the primary severe threat as low-level lapse rates gradually
steepen. But, some large hail may occur given favorable shear,
especially with any supercell. The severe risk will likely diminish
by the early to mid evening as thunderstorms push east of the coast.
...Upper Midwest...
Weak forcing aloft and the persistence of the upper ridge should
tend to limit convective development in an otherwise moderately to
strongly unstable airmass. Still, any thunderstorms which can
develop, perhaps aided by modest low-level warm advection this
evening/tonight, could pose an isolated severe hail/wind threat.
..Smith/Broyles.. 07/03/2025
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