Aug 29, 2026 2000 UTC Day 1 Convective Outlook
Updated: Sat Aug 29 19:49:07 UTC 2026 ( | | )
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
Probabilistic Tornado Graphic
Day 1 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
Day 1 Wind Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
CIG1
119,600
2,976,225
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
15 %
36,934
2,330,186
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
5 %
387,927
9,325,084
Phoenix, AZ...Tucson, AZ...Mesa, AZ...Glendale, AZ...Chandler, AZ...
Probabilistic Large Hail Graphic
Day 1 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
5 %
102,740
2,815,870
Salt Lake City, UT...West Valley City, UT...Provo, UT...West Jordan, UT...Orem, UT...
SPC AC 291949
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 PM CDT Sat Aug 29 2026
Valid 292000Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEVERE
THUNDERSTORMS FROM EASTERN NEVADA ACROSS NORTHERN UTAH INTO FAR
SOUTHWEST WYOMING...
...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and northern
Plains. Severe wind gusts are the main threat.
...20z Update...
No changes are needed to the current D1 Convective Outlook. See MCDs
#2167, #2168, and the previous discussion below for more
information.
..Thornton.. 08/29/2026
.PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 29 2026/
...Great Basin through the central Rockies...
Enhanced mid-level southwesterly flow aloft exists between the upper
ridging centered over the southern High Plains and a shortwave
trough moving through the Pacific Northwest. 12Z SLC sounding
sampled this enhanced flow well, reporting a belt of 50-55 kt wind
around 600 to 500 mb. This sounding also sampled the increased
mid-level moisture within this belt of stronger flow, resulting
precipitable water over 1.1".
Modest heating of this airmass is expected to foster moderate
buoyancy, although the widespread cloudiness could keep the airmass
from fully destabilizing. Most RAP soundings across the region
maintain lingering convective inhibition from UT into southern WY.
Even so, the combination of modest buoyancy, mid-level moisture, and
ascent attendant to a low-amplitude shortwave trough progressing
through the region will support scattered to numerous thunderstorms
from eastern NV across UT into northwest CO/southern WY. Some
isolated hail is possible with the strongest cores (which could
briefly acquire supercellular characteristics), but the primary
severe risk is strong to severe wind gusts. Highest severe coverage
is still expected from east-central NV into northern UT where the
greatest afternoon buoyancy is forecast.
...Northeast CO/eastern WY/NE Panhandle into the western/central
Dakotas...
High-based showers and thunderstorms along the leading edge of the
strongest ascent attendant to the shortwave trough moving through
the Great Basin and central Rockies should emerge into a diurnally
destabilized and moderately buoyant airmass from northeast CO into
eastern WY and the NE Panhandle during the late afternoon/early
evening. This could result in reintensification, and a risk for both
large hail and damaging gusts across the region throughout the
evening. Most of the guidance was overly aggressive with
destabilization and buoyancy across this region yesterday, and there
is some concern that cloud cover could again limit heating. That
being said, there is a pocket of greater low-level moisture across
SD and the region is currently under widely scattered cloud cover.
Enhanced westerly flow atop low-level easterlies will support at
least moderate deep-layer shear, so any updrafts that can mature
should be able to organize, with an attendant risk for large hail
and damaging gusts.
...AZ...
12Z PHX sounding sampled moderate mid-level moisture atop warm and
dry low levels. Scattered thunderstorm development is anticipated
across much of the region. Vertical shear is weak and a largely
disorganized storm mode is anticipated. Still, given the high storm
bases and steep low-level lapse rates, isolated strong to severe
gusts are possible this afternoon and evening.
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