Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0109 AM CDT Sun Aug 23 2026

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...MUCH OF CENTRAL MONTANA...AND PORTIONS OF THE
EASTERN GREAT BASIN...

...SUMMARY...
Strong-to-severe thunderstorms capable of large hail and damaging
winds will be possible across portions of the northern Rockies and 
northern Plains. Additional severe thunderstorms capable of damaging
winds will be possible across portions of northern Utah.

... Synopsis ...

A sub-tropical mid-level ridge will remain in place across much of
the West on Sunday, with a large-scale trough taking shape across
much of the East. A seasonably strong short-wave trough will crest
the ridge over southern Canada, with an attendant jet streak in its
basal region moving across Montana. Broadly northwest mid-level flow
will exist from the northern Plains east toward the Appalachians,
between the western ridge and eastern trough.


... Intermountain West ...

A well-mixed boundary layer will develop during the afternoon as
cooler mid-level temperatures associated with the approaching
short-wave trough overspread the northern Rockies. Scattered
thunderstorms should develop during the early to mid-afternoon
within an environment with steepening mid-level lapse rates.
Effective shear on the order of 30-40 knots will support multicell
clusters and transient supercell structures capable of producing
large hail and damaging wind gusts.

Farther south, multicell clusters should develop across eastern
Nevada and western Utah during the late afternoon. Modest mid-level
flow on the north side of the subtropical ridge, coupled with steep
low-level lapse rates (inverted-V profiles) should support efficient
downward momentum transfer with any sustained thunderstorm updraft.


... Northern Plains south into the Central High Plains ...

A plume of steep mid-level lapse rates will advect out from the
northern Rockies and overspread a moistening warm sector. The result
will be afternoon MUCAPE values between 2000-3000 J/kg. Although
vertical shear is not overly strong, forecast soundings/hodographs
suggest enough shear to support multicells and transient supercell
structures. Large hail will be possible with these initial
thunderstorms. With time, congealing outflows should support some
potential for upscale growth toward an MCS. Steep lapse rates will
support severe winds (some significant) with any organized
thunderstorm cluster.


... Northeast US ...

Early morning convection should dissipate enough to support at least
filtered sunshine during the late morning and early afternoon. This
will support temperatures warming into the 70Fs to perhaps low 80Fs.
This, when combined with upper 50Fs to low 60Fs dewpoints will
support between 500-1000 J/kg MUCAPE during the afternoon. Vertical
ascent downstream of the eastern trough will support clusters of
thunderstorms across the region. Modest mid-level lapse rates should
limit a more robust hail threat, but the degree of ascent and
instability will support a marginal risk of severe hail and damaging
wind.


... Northern Gulf Coast toward the Coastal Carolinas ...

Strong diurnal heating of a moist boundary layer (dewpoint
temperatures in the 70Fs) should support MUCAPE values between
3000-4000 J/kg during the afternoon. High precipitable water values
will support water-loaded updrafts capable of producing isolated
damaging downbursts with the strongest cells.


... Southern Arizona ...

Seasonably strong southeasterly mid-level flow will develop along
the periphery of the mid-upper-level ridge. This enhanced flow will
overspread a deeply mixed boundary layer (inverted-V) during the
afternoon. In spite of the deeply mixed boundary layer, precipitable
water values in excess of 1" will exist across the area during the
late afternoon. This will support at least isolated thunderstorm
clusters capable of producing damaging wind gusts.


... Southeast Kansas, Northeast Oklahoma, Southwest Missouri, and
Northwest Arkansas ...

A low amplitude mid-level trough will move southeast across the
Central US on Sunday, within the broader northwest flow. Although an
isolated thunderstorm cannot be ruled out with this feature during
the afternoon, the more likely scenario is the environment across
Kansas and Missouri remains capped during the afternoon.

By late evening, the mid-level trough/jet streak should be across
southern Missouri or northeast Arkansas, placing northeast Oklahoma
and southeast Kansas in the right entrance region of the mid-level
jet. Guidance is pretty confident in developing a strong low-level
jet across the southern Plains in response to this mid-level jet.
The result will be increasing warm-air advection/isentropic ascent
during the overnight. This will lead to scattered thunderstorm
development, with movement off to the east-southeast. Mid-level
lapse rates should only be on the order of 6.5 C/km, but
cloud-bearing shear around 30-40 knots should support strong
updrafts. DCAPE values between 500-1000 J/kg will support at least
marginally severe downbursts capable of wind damage.

..Marsh/Weinman.. 08/23/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1251 AM CDT Sun Aug 23 2026

Valid 241200Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE NORTHERN GREAT BASIN INTO THE CENTRAL HIGH PLAINS AND THE
NORTHERN PLAINS...THE SOUTHEAST...AND NORTHERN MAINE...

...SUMMARY...
Thunderstorms with at least isolated severe gusts/hail are possible
across the northern Great Basin to the High Plains and northern
Plains Monday afternoon and evening. A couple of damaging gusts may
also occur with storms in Maine and along parts of the Gulf Coast to
the eastern Carolinas.

...Northern Plains...
A mid-level shortwave trough will traverse the Canadian prairies on
Monday with some weak height falls overspreading North Dakota and
northern South Dakota. A weak surface low will accompany this trough
with a cold front extending into the Dakotas. Moderate to
potentially strong instability is forecast ahead of this cold front.
Subtle forcing from the height falls and weak convergence along the
front may support isolated storms during the afternoon/evening.
Long/straight hodographs would support supercells capable of large
hail and severe wind gusts. Steep lapse rates will support some
potential for 75+ mph wind gusts. In addition, if any longer lived
supercells can develop, 2+ inch hail is also possible. Stronger
forcing, hinted at by the more amplified mid-level trough on the 00Z
NAM, would support greater storm coverage and potentially greater
hail/wind probabilities in later outlooks. 

...Northern Great Basin into the central High Plains...
Widely scattered storms are forecast to develop over the higher
terrain from the northern Great Basin to the central Rockies. As
storms move into the adjacent Plains, where strong heating and steep
lapse rates are forecast, severe wind gusts are possible. Storm mode
will be single cell to multicell, with only 15 to 25 knots of shear
across the region. However, the thermodynamic profile will support
an isolated severe wind threat. 

...Southeast...
Temperatures in the mid to upper 80s amid mid 70s F dewpoints will
yield MLCAPE over 2000 J/kg from Louisiana to the North Carolina
coast. Despite weak tropospheric flow, enough moisture-fueled
buoyancy will support the potential for wet downbursts capable of
damaging gusts during the afternoon.

...Maine...
Deep-layer ascent ahead of an ejecting mid-level shortwave trough
will support scattered thunderstorm development during the late
morning into the afternoon hours across central and northern Maine.
A belt of 60 kt 500 mb southwesterly flow will pivot around the
upper trough and overspread Maine during the afternoon, when
buoyancy will be maximized. MLCAPE may exceed 750 J/kg with over 50
kts of effective bulk/speed shear. Therefore, any storms that
develop may become multicellular or transient supercellular in
nature, posting an isolated damaging gust/hail threat through the
afternoon.

..Bentley.. 08/23/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0228 AM CDT Sun Aug 23 2026

Valid 251200Z - 261200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHWESTERN
KANSAS AND VICINITY....

...SUMMARY...
Isolated strong to severe storms will be possible across portions of
the central Plains, the Southeast, and the Upper Midwest on Tuesday.
A more focused region of severe wind gusts is possible across
portions of the central High Plains.

...Upper Midwest...
A mid-level shortwave trough will move southeastward from the
Canadian Prairies into the Upper Midwest on Tuesday. A surface low,
and associated cold front, will move relatively quickly
southeastward through the day. Mid 60s dewpoints are forecast ahead
of this front which will result in moderate instability. Moderate
flow associated with the mid-level jet streak will provide ample
shear for storm organization. Storms will likely be ongoing at the
beginning of the period near the Canadian border which may result in
a somewhat messy storm mode through the day. However, farther south,
more isolated storm development is possible. Given storm motion
normal to the front and moderate mid-level flow, supercells will be
possible. Relatively weak mid-level lapse rates and warmer
temperatures aloft may limit the large hail threat somewhat. 

...Central Plains...
A reservoir of strong instability is forecast across the central
Plains where low 70s dewpoints are expected on Tuesday
afternoon/evening. A weak mid-level shortwave trough (perhaps
enhanced by Day 2 convection) is consistently shown among guidance
which should move across this region during the afternoon/evening.
The combination of a strongly unstable warm sector and forcing from
this mid-level shortwave trough should result in scattered to
widespread storm development Tuesday afternoon/evening. Effective
shear around 30 to 35 knots should result in a combination of
multicells and supercells initially with one or more clusters
developing by evening as storms grow upscale. The most favorable
region for a greater coverage of severe wind gusts will likely exist
across northwest Kansas and vicinity where diurnal timing is favored
and storm mode transition is expected.  

...Southeast...
Strong heating is expected along the Gulf Coast south of a frontal
zone. Shear will be very weak, but PWAT in excess of 2 inches and
the hot air mass should support water-loaded downdrafts capable of
isolated damaging wind gusts during the afternoon and early evening
hours. A slightly greater coverage of storms and severe potential
may exist across MS/AL downstream of early morning elevated
convection forecast to develop across the Mid-Mississippi Valley.

..Bentley.. 08/23/2026