Aug 28, 2026 1730 UTC Day 2 Convective Outlook
Updated: Fri Aug 28 17:25:30 UTC 2026 ( | | )
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
Day 2 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
SLIGHT
96,955
2,706,170
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
MARGINAL
334,053
3,433,351
Fort Collins, CO...Billings, MT...Boulder, CO...Greeley, CO...Longmont, CO...
Probabilistic Tornado Graphic
Day 2 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
Day 2 Wind Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
CIG1
205,589
3,577,222
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
15 %
97,547
2,707,475
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
5 %
333,335
3,479,005
Fort Collins, CO...Billings, MT...Boulder, CO...Greeley, CO...Longmont, CO...
Probabilistic Large Hail Graphic
Day 2 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
28,574
160,589
Bismarck, ND...Mandan, ND...
5 %
231,237
3,821,437
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
SPC AC 281725
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1225 PM CDT Fri Aug 28 2026
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN GREAT BASIN AND NORTHERN PLAINS...
...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin and northern Rockies. Severe wind gusts
are the main threat. Scattered severe storms are also likely across
portions of the northern High Plains, with potential for large hail
and damaging wind.
...Synopsis...
The axis of the western US ridge will shift eastward centering
across the Midwest D2/Saturday as a mid-level low digs southward
from the Pacific Northwest. Strengthening southwesterly flow aloft
will overspread the region from the northern Great Basin into the
northern Rockies/Intermountain west. With the increase in mid-level
flow across the northern Rockies, lee troughing will increase across
the central/northern Plains, with a lee cyclone developing across
the western Dakotas.
...Northern Great Basin into the Northern Rockies...
Widely scattered thunderstorms are expected to develop within a
broad region of greater ascent across the Northern Great Basin into
the Northern Rockies. Moisture will be primarily mid-level, with
deeply mixed profiles, steep low to mid-level lapse rates, and
fairly large dew point spreads near the surface. Though boundary
layer moisture will be limited, steep lapse rates and heating will
support at least moderate instability by the afternoon. With 40-50
kt 500 mb flow aloft, sufficiently strong deep layer speed shear
will promote a few organized storms and transient supercells capable
of damaging wind and marginally severe hail.
...Northern High Plains...
Upslope flow near the surface low in the Dakotas should promote
development of thunderstorms near the Black Hills and across
portions of the high terrain in eastern Wyoming/southeastern
Montana. Strengthening southerly flow will bring moisture northward,
with moderate to strong instability developing by the afternoon
across the western/central Dakotas. Elongated and largely straight
hodographs and deep layer shear around 40 kts will support
supercells capable of large hail and damaging wind.
Across eastern Wyoming, there is low confidence in a more organized
cluster evolving through time and moving into northern Nebraska.
Recent CAM guidance suggests a more focused corridor of severe wind
potential. The Marginal Risk was expanded southward to account for
this potential.
..Thornton.. 08/28/2026
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