Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1255 AM CDT Thu Aug 27 2026

Valid 271200Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC AND NORTHEAST...AND ALSO ACROSS PARTS OF
WESTERN/CENTRAL NE INTO NORTHWEST KS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Northeast today. Damaging wind, hail and a tornado or two may
accompany these storms. Large to very large hail and severe gusts
are also possible across parts of western Nebraska and northwest
Kansas.

...Mid-Atlantic/Northeast into parts of the central/southern
Appalachians...
An upper trough will remain in place over much of the eastern CONUS
today. Moderate destabilization will be possible along/ahead of a
weak surface trough/front extending from central NY/PA into the
central/southern Appalachians. Scattered thunderstorm development is
expected by mid/late afternoon, with sufficient deep-layer
flow/shear for some storm organization (especially from the northern
Mid-Atlantic into the Northeast). The strongest cells/clusters will
be capable of producing scattered damaging winds and at least
isolated hail. Modestly enlarged low-level hodographs may also
support some brief-tornado potential. Some severe threat may persist
into the evening before storms weaken and/or move offshore. 

Father south, deep-layer flow/shear will be weaker into parts of the
central/southern Appalachians, but scattered storm development
within a relatively warm and well-mixed environment will support
potential for localized strong/damaging gusts. 

...Central Plains...
Moderate to locally strong destabilization is expected across parts
of the central High Plains this afternoon, beneath modest
northwesterly mid/upper-level flow. While large-scale ascent will
generally remain rather modest, a subtle midlevel vorticity maximum
may aid in isolated to widely scattered storm development from far
southwest SD into western/central NE. Deep-layer shear will be
sufficient for supercells, with steep lapse rates and relatively
elongated hodographs supporting potential for large to very large
hail, in addition to a threat for localized severe gusts. 00Z CAM
guidance shows some uptick in storm coverage within this favorable
environment, and a 15% hail area has been added for parts of
west-central NE into northwest KS. Some guidance (notably the 00Z
HRRR) also shows upscale growth and an attendant swath of
severe-wind potential, though this scenario remains more uncertain.
Greater wind probabilities may eventually be needed if confidence
increases in the MCS scenario. 

Surrounding the Level-2/Slight Risk, a more isolated threat of
severe hail and wind may accompany the strongest cells from parts of
the Raton Mesa and CO Front Range vicinity into eastern WY. 

...Western/central Montana...
Despite rather limited low-level moisture, widely scattered storm
development is expected this afternoon across parts of
western/central MT, aided by strong heating and the influence of a
midlevel shortwave trough and jet maximum that are forecast to crest
the amplified upper ridge that is covering much of the interior
West. Steep lapse rates will support potential for localized
downbursts and strong to severe outflow gusts as storms spread
east-northeastward across MT.

...Northeast NV/northwest UT/southeast ID...
High-based storm development is also expected from parts of
northeast NV into northwest UT and southeast ID. While deep-layer
flow and storm organization will likely be somewhat weaker compared
to areas farther north, steep lapse rates and large DCAPE will
support potential for strong to severe outflow gusts from this
afternoon into the early evening. 

...South-central TX into the LA Gulf Coast region...
Uncertainty remains regarding how far south an ongoing storm cluster
and its attendant outflow will move across parts of LA/MS early this
morning. If this cluster persists to the beginning of the forecast
period (as forecast by the 00Z HRRR), then a localized wind-damage
threat will be possible near the immediate LA/MS Gulf Coast before
storms move offshore. If the cluster weakens and more substantial
recovery and diurnal destabilization occurs later today (as forecast
by more recent HRRR runs and some other HREF members), then storm
redevelopment will be possible by afternoon, potentially aided by a
remnant MCV. This scenario could also result in a localized
wind-damage threat. 

Farther west, scattered storm development is forecast across
south-central TX this afternoon, near a weak southward-moving cold
front. Deep-layer shear will likely remain quite weak, but moderate
buoyancy, large PW, and steep low-level lapse rates will support
potential for localized downbursts. Despite the weak shear, the
northerly flow regime may result in one or more outflow-driven
clusters that will move southward into the early evening before
weakening.

..Dean/Weinman.. 08/27/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1259 AM CDT Thu Aug 27 2026

Valid 281200Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR NORTH
GEORGIA INTO THE CAROLINAS AND VIRGINIA AND PORTIONS OF THE
NORTHERN/CENTRAL PLAINS....

...SUMMARY...
Isolated strong to severe storms are possible across northern
Georgia into the Carolinas and Virginia and the northern/central
Plains.

...North Georgia to the Carolinas...
Moderate to potentially strong instability is forecast to develop
south of a stalled cold front from the southern Appalachians to the
Mid-Atlantic where upper 60s to low 70s dewpoints will be present.
Lapse rates will be quite weak (~6 C/km), but most guidance shows
temperatures warming into the low to mid 80s which should provide
pockets of moderate to strong instability. Effective shear is
forecast to be weak (15 to 20 knots), but only slight modifications
in the effective layer calculation result in significantly greater
effective shear (30 to 35 knots) given moderate to strong flow above
7km. Therefore, any storms that can take advantage of this stronger
flow aloft may be longer-lived and capable of some damaging wind
gusts. 

...Central/Northern Nebraska into central and eastern South Dakota
and Vicinity...
A mid-level ridge will slowly deamplify through the day on Friday
across the northern Plains. As this occurs, lee troughing will
strengthen through the day with a lee cyclone forecast to develop
across western South Dakota by early Saturday morning. Strengthening
southeasterly flow ahead of the lee trough will advect low to
potentially mid 60s dewpoints into South Dakota. This will result in
moderate to potentially strong instability in the region. However,
most forecast soundings show the environment remaining capped for
much of the day which casts some doubt on diurnal storm coverage.
Some 00Z CAM guidance shows storms prior to 00Z across western
portions of the Marginal Risk area, but without strong forcing, it
is unclear if these storms will develop. Given the capped airmass,
the primary storm focus will likely be across northeast Nebraska and
eastern South Dakota, at the nose of the low-level jet where
warm-air advection will strengthen in the evening. Forecast
soundings show moderate to strong instability and strong shear
within this zone after 00Z. Large hail may be the primary threat in
the evening with the wind threat more dependent on potential upscale
growth.

..Bentley.. 08/27/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0228 AM CDT Thu Aug 27 2026

Valid 291200Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE NORTHERN GREAT BASIN AND THE NORTHERN PLAINS...

...SUMMARY...
Isolated strong to severe storms are possible in parts of the
northern Great Basin and across the northern Plains.

...Northern Great Basin Vicinity...
A broad range of 00Z guidance (GFS/RRFS/NAM) shows moderate
instability developing across northern Utah on Saturday amid strong
surface heating. Forecast soundings show an uncapped airmass by
mid-afternoon when scattered thunderstorm activity is expected to
begin. 45 to 50 knots of mid-level flow will support storm
organization/longevity and some damaging wind threat (some 75+ mph).
The ECMWF is the least unstable, with more cloud-cover across the
region, which may limit the severe weather threat somewhat.
Nonetheless, even this ECMWF solution would likely support some
severe wind threat. Therefore, a Marginal Risk seems warranted, and
if all guidance trends toward the more unstable solution, an upgrade
to Slight Risk may be needed in later outlooks. 

...Northern Plains...
Moderate to strong instability is forecast across the Northern
Plains on Saturday within a moist region to the north of a surface
low. Forcing will be relatively weak, but subtle height falls and
perhaps a weak mid-level shortwave trough embedded within the
southwesterly flow, may be sufficient for isolated to widely
scattered storms Saturday afternoon/evening. Forecast soundings show
long hodographs across the region which would support a supercell
storm mode. A Marginal Risk has been added for this threat, but the
lack of stronger forcing precludes higher probabilities at this
time.

..Bentley.. 08/27/2026