ACUS02 KWNS 240612
SWODY2
SPC AC 240610
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0110 AM CDT Sat Aug 24 2024
Valid 251200Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN
DAKOTAS INTO NORTHWESTERN MINNESOTA...
...SUMMARY...
Scattered severe storms may develop across the northern Plains area
on Sunday, with more isolated severe potential southwestward into
the southern Rockies on Sunday. A couple of strong/marginally
severe storms may also occur across the Lower Great Lakes/Upper Ohio
Valley vicinity.
...Synopsis...
A progressing western U.S. upper trough is forecast to gradually
weaken, as it impinges on a persistent central U.S. ridge. The
result will be that the trough gets shunted northeastward toward Montana/Wyoming
with time. Meanwhile, weak upper troughing will
persist over the Northeast.
At the surface, a cold front will progress eastward across the
Canadian Prairie, and the north-central U.S. with time. By the end
of the period, the front should stretch from Minnesota southwestward
to northeastern Colorado.
...Northern Plains southwestward to the Four Corners region...
As the western U.S. trough advances eastward, large-scale ascent
will support scattered thunderstorm development across the
Intermountain Region, within a diurnally destabilizing airmass.
While CAPE will remain limited, moderate southwesterly flow aloft
ahead of the trough will allow some storm organization/longevity at
time. This, combined with a deep mixed layer providing support for
enhanced downdrafts with the stronger cells, will result in risk for
locally severe wind gusts.
More substantial severe risk could evolve across portions of the
north-central states, where much greater instability will evolve.
Though the airmass should remain capped in most areas, ascent may be
sufficient to support local cap breaches by late afternoon to allow
isolated storm development. If storms develop, upscale growth near
convective outflows would be expected, possibly resulting in
evening/overnight MCS development. Large hail would be possible
with the initial storms, though with locally damaging gusts likely
to be the dominant risk. Still, given the capping that is
anticipated, and questions whether ascent will be sufficient to
allow storm development, will maintain only conditional 15%/SLGT
risk at this time.
...Lower Great Lakes/Upper Ohio Valley area...
On the western fringe of the northeastern U.S. trough, moderate
northwesterly flow aloft may combine with modest afternoon
destabilization to support isolated storm development. Assuming
this occurs, a few strong gusts would be possible as storms would
move rather quickly southeastward. The main question remains the
degree of destabilization which may occur, and thus will introduce
only 5%/MRGL risk at this time.
..Goss.. 08/24/2024
$$
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