ACUS02 KWNS 220606
SWODY2
SPC AC 220604

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0104 AM CDT Sun Jun 22 2025

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
LAKES/UPPER MIDWEST INTO THE CENTRAL PLAINS...

...SUMMARY...
Strong to potentially severe storms may develop on Monday from parts
of the Great Lakes into the central Plains.

...Synopsis...
A mid/upper-level shortwave trough initially over the northern
Plains and Canadian Prairies will move into Ontario on Monday, as a
surface low moves into Quebec. A trailing cold front will move
across parts of the northern/central Plains and upper Midwest/Great
Lakes. An expansive upper ridge will remain in place over much of
the eastern CONUS.

...Great Lakes/Upper Midwest...
Scattered storms may be ongoing Monday morning across parts of
MN/WI. While this convection will likely be somewhat elevated,
moderate MUCAPE and sufficient deep-layer shear could support an
isolated severe threat with the strongest early-day storms.

Diurnal heating/destabilization may support intensification of
morning storms, along with additional development in the vicinity of
the front during the afternoon into the evening. Relatively strong
diurnal heating will support moderate to locally strong buoyancy
along/ahead of the front, in areas not overly influenced by morning
convection. Unidirectional wind profiles and 25-40 kt in the 850-700
mb layer could support one or more outflow-driven clusters with a
threat of damaging wind and isolated hail.

...Central Plains vicinity...
Diurnal storm development will be possible Monday afternoon along
the front across parts of the central Plains, as well as within a
post-frontal regime into parts of the High Plains and Front Range.
Instability will be strongest along/ahead of the front, where the
strongest heating is expected, though deep-layer shear will be
rather weak across the warm sector. A few strong multicells or
clusters may develop near the front and pose a threat of localized
severe gusts. Given the expected widespread coverage of storms
within a favorable thermodynamic environment (with steep prefrontal
low-level lapse rates and large PW) for strong to severe gusts, the
Slight Risk has been extended into parts of the central Plains.

Effective shear will be stronger to the cool side of the front, due
to the presence of low-level east/northeasterlies beneath southwest
flow aloft. Coverage and intensity of post-frontal convection
remains somewhat uncertain, but isolated hail and strong to severe
gusts will be possible.

Guidance still varies somewhat regarding destabilization into parts
of the CO Front Range. Favorably veering wind profiles could support
isolated strong storms in this area if sufficient destabilization
can occur.

...Northern New England...
Strong instability will develop Monday afternoon across parts of the
Northeast and Mid Atlantic, though the influence of the upper ridge
will tend to suppress storm development across much of the region. A
warm advection regime will develop over northern New England, as
warmer low-level temperatures spread eastward. Storm development
cannot be ruled out within this regime, though most guidance
suggests warm temperatures aloft may tend to suppress convection.
Some guidance suggests convection may approach northern ME from
Quebec within a destabilizing environment. A conditional Marginal
Risk for damaging gusts has been added for this potential threat.

..Dean.. 06/22/2025

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