Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Tue Jul 22 2025
Valid 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN PLAINS INTO NORTHERN MN...
...SUMMARY...
Scattered severe thunderstorms are expected over parts of the
northern Plains into the upper Mississippi Valley later today into
tonight.
...Northern Plains into the Upper Great Lakes region...
An active severe-weather day still appears possible across parts of
the northern Plains into the upper MS Valley/Great Lakes, though
considerable uncertainty remains regarding the evolution of storms
through the day.
One or more storm clusters and possibly a remnant MCS may be ongoing
at the start of the period somewhere from eastern ND into northern
MN, though guidance varies regarding the details. Any organized
cluster or MCS that is ongoing may pose a threat for at least
localized damaging gusts into parts of northern MN through the
morning, along with some hail potential with any semi-discrete
cells.
A surface low is forecast to move eastward across SD through the
day, downstream of a positively tilted upper-level trough over the
northern Rockies. An outflow-influenced surface boundary will extend
northeast from the low into parts of the eastern Dakotas and
northern MN, though its placement is somewhat uncertain by
afternoon. Strong instability will develop by afternoon near and
south of the boundary, and also within a region of moist
east/northeasterly flow north and northwest of the surface low. The
strongest mid/upper-level flow will be north of the boundary, but
backed low-level flow near the boundary will result in favorable
deep-layer shear for organized convection.
There will be some potential for supercell development near the
surface low and northeastward along the boundary during the
afternoon and evening, though coverage is uncertain due to rather
subtle large-scale forcing. Any sustained supercells within this
environment could pose some tornado threat, in addition to potential
for large to very large hail and localized severe gusts. Greater
tornado probabilities may be needed if confidence increases in
supercell development during the afternoon and evening.
Farther west, widely scattered storm development is again expected
across parts of MT and northern WY, initially within the
post-frontal environment. Moderate instability and favorable
deep-layer shear will support a mixture of cells and clusters with
hail and severe-wind potential as they move east-northeastward. With
time, upscale growth will be possible, either from convection moving
out of the northern High Plains, or from storms developing farther
east near the surface boundary. This could result in potential for a
swath of damaging winds during the evening and overnight, though the
favored corridor for this potential remains uncertain at this time.
...IA into southern MN/WI...
An MCV generated by the extensive MCC over the central Plains Monday
evening is forecast by most 00Z guidance to move northeastward
toward IA and southern MN/WI through the period. The extent of flow
enhancement and storm development associated with this feature is
uncertain, but it is forecast to track across a moist and unstable
environment during the afternoon and evening, and could aid in the
development of a few strong storms. Locally damaging gusts will be
possible, and a tornado cannot be ruled out if the MCV remains
somewhat vigorous.
...Parts of the Southeast...
A weak cold front will move across parts of the Carolinas and
Georgia today into this evening. Very rich moisture (PWs above 2
inches) will support scattered to numerous thunderstorms along/ahead
of the front, and in association with the sea breeze. Strong to
locally damaging gusts will be possible, mainly during the afternoon
and evening.
...Southern/central Rockies/High Plains...
Relatively high-based thunderstorms are again expected this
afternoon and evening across parts of the central/southern Rockies
and adjacent High Plains. Localized strong to severe gusts may
accompany these storms, though with relatively modest buoyancy and
weak deep-layer shear, the threat appears too disorganized and
nebulous for probabilities at this time.
..Dean/Wendt.. 07/22/2025
Read more CHECK UPDATE ZOOM GRAPHIC
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