SPC Aug 30, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 PM CDT Sat Aug 29 2026

Valid 300100Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE GREAT
BASIN AND CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and
northern/central Plains. Isolated severe wind gusts are the main
threat, though some hail is also possible.

...Great Basin and Rockies...
An upper low, and several weak perturbations embedded within a belt
of enhanced mid-level flow with moving across the Great Basin are
supporting scattered thunderstorms across the eastern Great Basin
and Intermountain West this evening. Plentiful monsoon moisture
remains in place contributing to modest buoyancy. This will support
scattered to numerous storms through much of the evening and
overnight. 50-55 kt of mid-level flow, and relatively dry sub cloud
layers will continue to support strong downdrafts with the potential
for severe wind gusts and isolated hail. This appears most likely
across eastern NV and northern UT where the air mass remains the
most unstable. However, sporadic damaging gusts are possible across
much of the Rockies and Four Corners where storms are forecast to
remain active tonight.

...Central Plains...
High-based convection across eastern CO/WY and western NE has
gradually weakened as it has encountered a much drier and more
stable air mass across the High Plains. Isolated strong to severe
gusts will remain possible with this activity, and other
showers/storms emanating from the terrain this evening.

More isolated storms, including supercells, across eastern SD are
expected to continue this evening with isolated hail and severe wind
potential. As the lead shortwave trough continues eastward this
evening, increasing low-level warm advection could support
additional elevated storm development from eastern SD to
south-central ND. Moderate buoyancy atop the stable surface layer
amid 40-50 kts of effective shear would support supercells with
isolated hail possible through the overnight hours.

...AZ...
Scattered thunderstorms ongoing across southern AZ should slowly
drift northwest through this evening within a very hot and
moderately unstable air mass. Vertical shear is weak and a largely
disorganized storm mode is likely. Still, steep low-level lapse
rates will favor strong downdrafts with isolated severe gusts
possible.

..Lyons.. 08/30/2026


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SPC Aug 29, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


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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SPC Aug 29, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat Aug 29 2026

Valid 291630Z - 301200Z

...THERE IS A SLIGHT RISK OF 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.

...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.

..Mosier/Moore.. 08/29/2026


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SPC Aug 29, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 PM CDT Fri Aug 28 2026

Valid 290100Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
BASIN...TO THE CENTRAL ROCKIES AND NORTHERN PLAINS...

...SUMMARY...
Isolated strong to severe storms are possible across the northern
Plains, and from parts of the Great Basin and Desert Southwest into
the Rockies.

...Great Basin/Rockies...
Evening water vapor imagery showed an expansive area of high
pressure centered over the Four Corners with broad southwesterly
flow aloft ongoing over much of the Great Basin and Rockies. To the
west of the ridge, an upper low and broad trough were moving onshore
across the Pacific Northwest and CA respectively. Ahead of these
features, several weaker perturbations and a plume of mid-level
moisture were contributing to widely scattered thunderstorms over
the Great Basin and central Rockies this evening.

Despite limited buoyancy owing to expansive cloud cover, plentiful
monsoon moisture should continue to support widely scattered
high-based thunderstorms this evening and into the overnight hours.
At least isolated strong to severe gusts are possible owing to dry
low-levels suitable for strong downdrafts with the established
storms/clusters. This appears most likely from far eastern NV,
across northern UT, and into central WY where the air mass remains
the warmest.

...Northern Plains...
The first of the mid-level shortwave troughs embedded within the
broader southwest flow are expected to eject eastward over the
northern Plains tonight. As ascent from the wave overspreads a warm
front, the low-level jet is forecast to strengthen (40-50 kt),
supporting a broad area of low-level warm air advection across the
eastern Dakotas into MN/IA. Elevated storms should develop near the
front with moderate buoyancy and deep-layer shear supportive of
supercells. Some hail risk is possible with these storms overnight.
Given the increasing forcing for ascent, upscale growth into a
cluster or MCS is possible, which could result in a low-probability
risk for damaging gusts over southwest MN and adjacent northwest IA
through 12z Saturday.

...Mid Atlantic to the Southeast...
Several clusters of scattered thunderstorms remain ongoing ahead of
a weak front from VA to the northern Gulf Coast. These storms have
slowly weakened through the evening and should continue to do so
with the loss of diurnal heating. Ahead of the front, high PWAT
content (2-2.5 inches) may still support a sporadic downbursts with
the stronger clusters this evening. However, weak shear and waning
diurnal buoyancy suggest an organized or expansive severe threat is
unlikely.

..Lyons.. 08/29/2026


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