365
ACUS02 KWNS 170531
SWODY2
SPC AC 170530

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 AM CDT Thu Jul 17 2025

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NEBRASKA...SOUTH DAKOTA...AND SOUTHERN MINNESOTA INTO IOWA...AND
ACROSS PORTIONS OF THE SOUTHERN MID-ATLANTIC...

...SUMMARY...
Strong to severe thunderstorms are possible across portions of South
Dakota and Nebraska into southern Minnesota and Iowa. Additional
strong to severe storms may occur across portions of West Virginia,
Virginia and North Carolina.

...NE/SD/MN/IA...

Stronger mid/upper level westerly flow will remain confined to the
northern tier of the U.S. from the northern Plains to New England.
Shortwave impulses will migrate through the westerly flow, but
stronger instability will remain displaced to the south of the belt
of stronger flow. Nevertheless, a weak surface low and attendant
trough is forecast to develop over the northern/central High Plains,
and a stalled front will gradually lift north across the northern
Plains and portions of the Midwest. Rich boundary layer moisture and
a plume of steep midlevel lapse rates will support strong
destabilization across parts of KS/NE/SD and the Mid-MO Valley.

Vertically veering wind profiles will support rotating storms, while
elongated/straight hodographs above 2-3 km appear favorable for
hail. Steep low-level lapse rates, and some modest dry air noted
between 700-500 mb suggest damaging wind potential is also possible.
While some modest low-level hodograph curvature is noted, 0-1 km
shear is expected to remain modest, though a tornado or two cannot
be ruled out.

While this environment generally appears favorable for at least
isolated supercells, convective evolution is uncertain given
somewhat subtle forcing. Additionally, forecast height tendencies
are neutral to possibly small height rises as a shortwave upper
ridge builds over the MT/WY after 21z. Capping across portions of
the region could limit coverage. Where capping is not an issue,
strong instability and modest shear could result in rapid
clustering. Furthermore, early convection may be ongoing across
parts of ND/SD into MN. How these storms and associated cloudiness
evolve through the morning, and any potential outflow generated by
this convection also result in uncertainty. Given these
uncertainties, despite a favorable airmass, will maintain Marginal
(level 1 of 5) probabilities with some expansion of the area.
Outlook upgrades may be necessary later if some of the
aforementioned uncertainties are resolved.

...Southern Mid-Atlantic vicinity...

A weak shortwave impulse is forecast to migrate across the Blue
Ridge to the Mid-Atlantic coast in modest westerly flow on the
northern periphery of the upper high. A very moist airmass will
support moderate destabilization. While shear will remain modest,
multicell clusters could produce strong downbursts. If storms can
organize along consolidating outflows, increasing potential for
damaging winds will occur.

..Leitman.. 07/17/2025

$$