SPC Aug 31, 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
0757 PM CDT Sun Aug 30 2026

Valid 310100Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Severe storms capable of damaging wind gusts remain likely across
portions of the northern Plains this evening.

...Northern Plains...
Evening water-vapor imagery showed a strong, negative-tilt mid-level
low and embedded shortwave trough ejecting eastward across southern
SK into eastern MT. Accompanying the low, a prominent mid-level jet
streak (60-70 kt) was quickly moving across the Rockies and into the
Plains. A cold front, attendant to a surface low in southern Canada,
will sweep quickly eastward across the Dakotas tonight.

A well-develop squall line was observed along/ahead of the front
from southern SK/MB to northern SD this evening. Within the line,
numerous strong to severe gusts have been observed thus far. Aided
by the enhanced mid-level flow ahead of the advancing upper trough,
ascent will continue to support the line as it moves eastward this
evening. The air mass downstream in the eastern Dakotas has remained
sheltered much of the day, but is very moist with dewpoints in the
upper 60s to low 70s F. Given the presence of an established cold
pool and sufficient deep-layer shear, especially along the southern
portions of the squall line, the severe threat may continue eastward
this evening across southern ND and SD into the late evening hours,
with a risk for damaging gusts.

Eventually, increasing nocturnal inhibition and the weaker buoyancy
should favor a decreasing severe risk. Convection may transition to
more elevated structures above the more stable PBL with an isolated
risk for occasional damaging gusts and some hail into the overnight
hours across eastern ND and western MN.

...Central Rockies and High Plains...
At the base of the upper low and shortwave, scattered thunderstorms
were ongoing from eastern UT into western/central CO this evening.
Enhanced mid-level flow is supporting organized clusters and some
rotating storms. Hail or severe gusts are possible. Convection
should weaken as it enters the more stable and cooler higher terrain
across central CO. Sporadic strong gusts or small hail remain
possible withe more robust storms in the mountains through tonight.

East of the Divide, high-based showers and thunderstorms should
increase in coverage this evening as a secondary mid-level vorticity
maximum moves out over the Plains. Increasing ascent amid warm
surface temperatures and steep low-level lapse rates (00z DDC
sounding) should support strong downdrafts capable of severe gusts
in the 60-75 mph range. 30-40 kt of deep-layer shear will support
some conglomeration with hi-res model guidance showing a cluster or
weak MCS moving across the High Plains of eastern CO, and western
KS/NE this evening/tonight.

...AZ...
Scattered thunderstorms over the lower deserts should persist
through this evening given very hot surface temperatures and
seasonable monsoon moisture. Moderate buoyancy but weak deep-layer
shear should support multicell storms. Steep low-level lapse rates
could result in a few strong to severe gusts this evening.

..Lyons.. 08/31/2026


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SPC Aug 30, 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
0246 PM CDT Sun Aug 30 2026

Valid 302000Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST MONTANA AND FAR NORTHEAST WYOMING INTO THE
CENTRAL DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...20z Update...
Only minor changes were made to remove the Marginal Risk from behind
ongoing convection in eastern Montana. Otherwise, the D1 Convective
Outlook remains on track. See previous discussion and MCD #2174 for
more information.

..Thornton.. 08/30/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Sun Aug 30 2026/

...Northern High Plains into the northern Plains...
Recent satellite imagery shows a well-defined shortwave trough
moving eastward across southern Saskatchewan and western MT/eastern
ID. A belt of stronger westerly flow aloft likely exists within the
base of this trough from eastern ID into western WY. Recent
mesoanalysis estimates 50 to 60 kt at 500 mb, but its actual
magnitude is uncertain. Showers and isolated thunderstorms are
already ongoing downstream of this wave, and the general expectation
is for these showers and thunderstorms to persist as the wave moves
eastward, eventually encountering a notably more unstable airmass
downstream.

Current surface observations show mid 60s dewpoints into the western
Dakotas, with upper 50s/low 60s dewpoints farther west in eastern
MT. Afternoon high temperatures are expected range from the low to
mid 80s along the MT/ND border into the low 90s farther south into
southwest SD. Despite relatively poor pre-frontal mid-level lapse
rates, the resulting temperature/dewpoint combination will support
MLCAPE ranging from around 500-1000 J/kg across eastern MT and the
western Dakotas to closer to 2000 J/kg across the central Dakotas.
Some low-level stability may linger, but should be overcome by the
strong forcing, and the development of a line of strong to severe
storms is anticipated. Strong to severe gusts will be the primary
risk, with some instance of gusts from 65 to 80 mph possible.
Maximum storm intensity and highest severe coverage is currently
forecast to occur from the ND/SD/MT border intersection vicinity
eastward into south-central ND and north-central SD. Decreasing
buoyancy is expected from the central Dakotas eastward, with
gradually decreasing storm intensity expected as the line of storms
moves into this region this evening.

...Central High Plains...
Increased coverage and depth of the thunderstorms across UT indicate
the presence of secondary area of ascent south of the primary
shortwave trough, perhaps tied to a convectively augmented vorticity
maximum. Expectation is for this vorticity maximum to progress
eastward, persisting across the central Rockies before entering
deeply mixed boundary-layer in place over the central High Plains.
High-based storm character coupled with steep low-level lapse rates
will support the development of strong outflow, and gusts from 60 to
75 mph are possible.

...UT/Western CO...
Thunderstorms are already ongoing from eastern UT into western CO,
and deep-layer vertical shear is already strong enough to support
organization within any more persistent updrafts. A few instances of
hail and/or damaging gusts are possible with this activity.
Additionally, considerable low-level moisture will remain over UT
today, leading to another round of strong to isolated severe
thunderstorms this afternoon. Deep-layer shear will remain
sufficient for rotating storms capable of damaging wind gusts and
hail. This additional activity should also spread into western CO
before weakening this evening.

...Central/Southern AZ...
Ample low-level moisture remains in place across much of AZ, with
upper 50s dewpoints across northern AZ increasing into the mid 60s
across southern AZ. Another day of afternoon thunderstorms is
anticipated as this moist airmass destabilizes amid strong diurnal
heating. High-based storms coupled with moderate buoyancy and steep
low-level lapse rates could result in a few strong to severe gusts
across the region this afternoon and evening.


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SPC Aug 30, 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 Sun Aug 30 2026

Valid 301630Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST MONTANA AND FAR NORTHEAST WYOMING INTO THE
CENTRAL DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...Northern High Plains into the northern Plains...
Recent satellite imagery shows a well-defined shortwave trough
moving eastward across southern Saskatchewan and western MT/eastern
ID. A belt of stronger westerly flow aloft likely exists within the
base of this trough from eastern ID into western WY. Recent
mesoanalysis estimates 50 to 60 kt at 500 mb, but its actual
magnitude is uncertain. Showers and isolated thunderstorms are
already ongoing downstream of this wave, and the general expectation
is for these showers and thunderstorms to persist as the wave moves
eastward, eventually encountering a notably more unstable airmass
downstream.

Current surface observations show mid 60s dewpoints into the western
Dakotas, with upper 50s/low 60s dewpoints farther west in eastern
MT. Afternoon high temperatures are expected range from the low to
mid 80s along the MT/ND border into the low 90s farther south into
southwest SD. Despite relatively poor pre-frontal mid-level lapse
rates, the resulting temperature/dewpoint combination will support
MLCAPE ranging from around 500-1000 J/kg across eastern MT and the
western Dakotas to closer to 2000 J/kg across the central Dakotas.
Some low-level stability may linger, but should be overcome by the
strong forcing, and the development of a line of strong to severe
storms is anticipated. Strong to severe gusts will be the primary
risk, with some instance of gusts from 65 to 80 mph possible.
Maximum storm intensity and highest severe coverage is currently
forecast to occur from the ND/SD/MT border intersection vicinity
eastward into south-central ND and north-central SD. Decreasing
buoyancy is expected from the central Dakotas eastward, with
gradually decreasing storm intensity expected as the line of storms
moves into this region this evening.

...Central High Plains...
Increased coverage and depth of the thunderstorms across UT indicate
the presence of secondary area of ascent south of the primary
shortwave trough, perhaps tied to a convectively augmented vorticity
maximum. Expectation is for this vorticity maximum to progress
eastward, persisting across the central Rockies before entering
deeply mixed boundary-layer in place over the central High Plains.
High-based storm character coupled with steep low-level lapse rates
will support the development of strong outflow, and gusts from 60 to
75 mph are possible.

...UT/Western CO...
Thunderstorms are already ongoing from eastern UT into western CO,
and deep-layer vertical shear is already strong enough to support
organization within any more persistent updrafts. A few instances of
hail and/or damaging gusts are possible with this activity.
Additionally, considerable low-level moisture will remain over UT
today, leading to another round of strong to isolated severe
thunderstorms this afternoon. Deep-layer shear will remain
sufficient for rotating storms capable of damaging wind gusts and
hail. This additional activity should also spread into western CO
before weakening this evening.

...Central/Southern AZ...
Ample low-level moisture remains in place across much of AZ, with
upper 50s dewpoints across northern AZ increasing into the mid 60s
across southern AZ. Another day of afternoon thunderstorms is
anticipated as this moist airmass destabilizes amid strong diurnal
heating. High-based storms coupled with moderate buoyancy and steep
low-level lapse rates could result in a few strong to severe gusts
across the region this afternoon and evening.

..Mosier/Moore.. 08/30/2026


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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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