SPC Aug 28, 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
1130 AM CDT Fri Aug 28 2026

Valid 281630Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
CENTRAL/NORTHERN PLAINS...GREAT BASIN AND DESERT SOUTHWEST INTO THE
NORTHERN ROCKIES...NORTH GA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN ME......

...SUMMARY...
Isolated strong to severe storms are possible across the central and
northern Plains, northern Georgia into the Carolinas and
Mid-Atlantic, central and eastern Maine, and from parts of the Great
Basin and Desert Southwest into the northern Rockies.

...Maine...
Morning surface analysis places a low over eastern Quebec, with a
cold front extending southward from this low through northern NY
before arcing more southwestward and becoming increasingly diffuse
across the Upper OH Valley. A shortwave trough is forecast to
progress through southern Quebec towards the St. Lawrence Valley
today. The surface low is forecast to eject northeastward in
response, with its attendant cold front sweeping eastward across ME.
A moist airmass precedes this front, with current observations
sampling mid to upper 60s dewpoints. This airmass should destabilize
amid filtered daytime heating ahead of the front, although poor
mid-level lapse will limit the overall buoyancy. Scattered
thunderstorm development is anticipated as the cold front interacts
with this modestly buoyant airmass. A few strong to severe storms
are possible, but deep-layer shear largely parallel to the frontal
boundary will contribute to a predominantly linear mode and a likely
trend toward undercutting of new updrafts. Even so, any updrafts
that can mature could organize, potentially becoming supercell
storms capable of locally wind gusts and hail.

...Mid-Atlantic into Georgia...
Morning surface analysis places a low off the southern New England
coast and another over southern NJ (near the ongoing thunderstorms).
A weak front extends through these two lows, continuing
southwestward across the Carolina Piedmont into northern GA. Widely
scattered thunderstorms are expected to form along
the front this afternoon, with slow-moving but strong storms
possible. The stronger (but still modest) deep-layer shear will
occur across VA and NC, with the stronger buoyancy displaced farther
south across SC and GA. Even so, the expectation is that a
combination of moderate CAPE, high PWAT values, and limited
deep-layer shear will promote isolated strong storms capable of
water-loaded downbursts.

...Great Basin through Wyoming..
A belt of stronger mid-level flow currently extends from central CA
through the northern Rockies between the upper troughing over
western Canada and the upper ridging centered over the Four Corners.
Low-amplitude shortwave troughs embedded within this enhanced flow,
and associated ascent and mid-level moisture, will contribute to
thunderstorm development this afternoon. A deeply mixed boundary
layer is anticipated throughout much of this region, suggesting any
of the stronger, more persistent storms could produce damaging
gusts. Highest storm coverage is expected from eastern NV into
central/northern UT, resulting in a relatively greater threat for
damaging gusts within this corridor.

...Dakotas into western Minnesota and northern Iowa...
There could potentially be two rounds of convection across the
northern Plains today. The first will be with any of the high-based
convection from WY as it spreads eastward into western
Dakotas, where greater low-level moisture and buoyancy will be in
place. The greater buoyancy could result in reintensification and a
few bowing structures capable of producing locally damaging wind
gusts and hail.

Additional warm-air advection associated development is then
possible later this evening as the low-level jet strengthens over
the Plains. These elevated storms should develop within an
environment characterized by moderate buoyancy and deep-layer shear,
suggesting a few supercells capable of large hail are possible
initially. Over time, some upscale growth is possible, which could
result in a low-probability risk for damaging gusts over southwest
MN and adjacent northwest IA early tomorrow morning.

..Mosier/Moore.. 08/28/2026


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SPC Aug 28, 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
0809 PM CDT Thu Aug 27 2026

Valid 280100Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
WEST-CENTRAL NE INTO NORTHWEST KS...NORTHERN MID-ATLANTIC...AND
WEST-CENTRAL MT...

...SUMMARY...
Storms capable of producing severe hail and wind remain possible
this evening across west-central Nebraska into northwest Kansas.
Localized wind damage also remains possible over parts of the
Mid-Atlantic and Northeast. Storms with localized severe gusts will
continue through the evening across west-central Montana.

...Central Plains...
Earlier supercells have congealed into a small southward-moving
cluster across northwest NE. Steep lapse rates, strong buoyancy
(MLCAPE of 2000-3000 J/kg) and effective shear of 40-50 kt (as
observed on the 00Z LBF sounding) within a northwesterly flow regime
will continue to support organized storms through the evening. The
severe-wind (potentially exceeding 75 mph) threat associated with
this small MCS is expected to spread towards parts of southwest NE
and northwest KS. Any embedded supercells or discrete cells along
the periphery of the cluster will also remain capable of producing
large hail, given the favorable thermodynamic environment and
relatively elongated hodographs. Longevity of this cluster into late
tonight is uncertain, due to increasing MLCINH and generally modest
large-scale ascent. Some severe potential could spread as far as
west-central/southwest KS before diminishing.

...Parts of the Mid-Atlantic/Northeast...
Scattered strong to locally severe storms are ongoing this evening
from the northern Mid-Atlantic into parts of the Northeast. While
substantial convective overturning has occurred, a corridor of
moderate MLCAPE remains in place from northern VA into eastern PA
and southeast NE. A short-term threat for locally damaging wind and
perhaps marginal hail may continue before storms generally weaken by
late evening. See MCD 2157 for more information.

...West-central MT...
High-based convection is ongoing early this evening across parts of
west-central MT. Weak buoyancy will continue to hamper storm
intensity, but the favorable lapse rate environment will continue to
support potential for strong to severe gusts. See MCD 2158 for more
information.

...Parts of south-central TX...
Scattered storms across south-central TX are ongoing near a
southward-moving composite outflow. These storms may be capable of
producing localized damaging gusts through dusk, before weakening
with the onset of nocturnal cooling/stabilization.

..Dean.. 08/28/2026


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SPC Aug 27, 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
0251 PM CDT Thu Aug 27 2026

Valid 272000Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC/NORTHEAST...CENTRAL PLAINS...AND CENTRAL MONTANA...

...SUMMARY...
Scattered strong to severe thunderstorms remain possible across
parts of the Northeast and Mid-Atlantic today. Damaging winds,
severe hail, and a tornado or two may accompany these thunderstorms.
Large to very large hail and severe gusts are also possible across
parts of northern High Plains and central Plains.

...20z Update...

The forecast remains on track with only minor changes made to the
existing outlook. See the discussion below as well as MCDs 2148,
2149, and 2150 for additional details.

..Chalmers/Thornton.. 08/27/2026

.PREV DISCUSSION... /ISSUED 1124 AM CDT Thu Aug 27 2026/

...Mid-Atlantic/Northeast...
Recent surface analysis places a low over western Quebec, with a
cold front arcing from this low southwestward through the middle OH
Valley, western TN Valley and then westward across central AR and
central OK. Satellite imagery reveals a shortwave trough extending
from northeastern Ontario through western PA, just west of the
analyzed surface low. There also appears to be a more subtle
shortwave trough farther south moving through WV towards VA.

Expectation is for the primary shortwave trough and cold front to
continue eastward, interacting with the very moist airmass across
the Northeast to support thunderstorm development this afternoon.
12Z ILN and PIT soundings sampled the moderate westerly flow aloft,
supporting the potential for strong multicells along both the cold
front and pre-frontal troughing. A few supercells are possible if
warm sector development can mature without too much interaction with
other convection. Primary risk will be damaging gusts, although the
modestly cool temperatures aloft (i.e. -10 to -12 deg C at 500-mb)
suggest some hail is possible as well.

A somewhat displaced area of earlier thunderstorm development is
manifesting across the northern Mid-Atlantic. As mentioned in MCD
#2145, a broken band of thunderstorms is ongoing as of mid-morning
from the New York City vicinity southwest toward Baltimore, with
that activity potentially being aided by forcing for ascent
associated with the subtle shortwave trough moving into VA. Airmass
across this region is very moist, and instability is steadily
building under modest diurnal heating. Most guidance suggests this
activity gradually increases in coverage and intensity over the next
few hours. The presence of a vertically veering wind profile
with around 30 to 35 kt of effective bulk shear would support a
conditional risk for embedded supercell structures capable of
locally damaging winds, marginally severe hail, and perhaps a brief
tornado.

...Northern Rockies/High Plains...
Recent satellite imagery depicts a shortwave trough progressing
across eastern OR towards ID and western MT. Moderate mid-level
moisture and forcing for ascent associated with this wave are
forecast to initiate thunderstorms across the northern Rockies this
afternoon. This activity is then forecast to progress northeastward
off the higher terrain into central MT, where a deeply mixed airmass
is forecast to be in place. Despite this deep mixing and somewhat
limited low-level moisture, the mid-level moisture associated with
the shortwave will allow for at least modest buoyancy (i.e. MLCAPE
over 500 J/kg). This should support storm maintenance off the
terrain, with a trend towards outflow-dominant bowing segments with
time. Primary severe risk is damaging gusts, including the potential
for gusts from 65 to 75 mph.

...Central Plains...
Moist southerly flow will help maintain moderate low-level moisture
through the NE Panhandle and into southwest SD amid the strong
heating and boundary-layer mixing expected this afternoon.
Additionally, this modest, but persistent, warm-air advection is
likely to force convective initiation this afternoon over the
western NE/SD border vicinity. Low-level southerly flow veering to
moderate northwesterlies aloft will support deep-layer shear of 40
to 50 kt, more than adequate for supercell development with any
mature convective. Any sustained supercells will be capable of
producing large hail (some 2+ inches) as they track
south-southeastward through the late afternoon into the evening.
Upscale growth into one or more bowing segments appears likely this
evening, with strong to severe gusts (65 to 75 mph) possible.

An isolated threat for severe hail/gusts may also exist
farther west/south across the CO Front Range to Raton Mesa vicinity.
Weaker buoyancy and deep-layer shear should keep any more organized
updrafts confined to the higher terrain and Foothills.

-- No other changes needed to the outlook with the text for the
additional areas appended from the 13Z Outlook below --

...Great Basin...
High-based thunderstorms should also develop this afternoon across
portions of northeast NV into northwest UT and southeast ID. While
low/mid-level winds and related thunderstorm organization will
likely be somewhat weaker/limited compared to areas farther north,
steep lapse rates and large DCAPE will support potential for strong
to severe outflow gusts as this convection spreads northeastward
into the early evening.

...South-Central/Coastal Texas into Southern Louisiana...
Ongoing thunderstorms across southern LA may pose a threat for gusty
winds this morning before they move offshore. Additional
thunderstorms may develop this afternoon from parts of south-central
TX towards the upper TX Coast, with isolated severe/damaging
downburst winds possible given ample moisture/instability forecast.
Weak deep-layer shear should limit the overall severe threat.


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SPC Aug 27, 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
1124 AM CDT Thu Aug 27 2026

Valid 271630Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC/NORTHEAST...THE CENTRAL PLAINS...AND CENTRAL
MONTANA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Northeast and Mid-Atlantic today. Damaging winds, severe
hail, and a tornado or two may accompany these thunderstorms. Large
to very large hail and severe gusts are also possible across parts
of northern High Plains and central Plains.

...Mid-Atlantic/Northeast...
Recent surface analysis places a low over western Quebec, with a
cold front arcing from this low southwestward through the middle OH
Valley, western TN Valley and then westward across central AR and
central OK. Satellite imagery reveals a shortwave trough extending
from northeastern Ontario through western PA, just west of the
analyzed surface low. There also appears to be a more subtle
shortwave trough farther south moving through WV towards VA.

Expectation is for the primary shortwave trough and cold front to
continue eastward, interacting with the very moist airmass across
the Northeast to support thunderstorm development this afternoon.
12Z ILN and PIT soundings sampled the moderate westerly flow aloft,
supporting the potential for strong multicells along both the cold
front and pre-frontal troughing. A few supercells are possible if
warm sector development can mature without too much interaction with
other convection. Primary risk will be damaging gusts, although the
modestly cool temperatures aloft (i.e. -10 to -12 deg C at 500-mb)
suggest some hail is possible as well.

A somewhat displaced area of earlier thunderstorm development is
manifesting across the northern Mid-Atlantic. As mentioned in MCD
#2145, a broken band of thunderstorms is ongoing as of mid-morning
from the New York City vicinity southwest toward Baltimore, with
that activity potentially being aided by forcing for ascent
associated with the subtle shortwave trough moving into VA. Airmass
across this region is very moist, and instability is steadily
building under modest diurnal heating. Most guidance suggests this
activity gradually increases in coverage and intensity over the next
few hours. The presence of a vertically veering wind profile
with around 30 to 35 kt of effective bulk shear would support a
conditional risk for embedded supercell structures capable of
locally damaging winds, marginally severe hail, and perhaps a brief
tornado.

...Northern Rockies/High Plains...
Recent satellite imagery depicts a shortwave trough progressing
across eastern OR towards ID and western MT. Moderate mid-level
moisture and forcing for ascent associated with this wave are
forecast to initiate thunderstorms across the northern Rockies this
afternoon. This activity is then forecast to progress northeastward
off the higher terrain into central MT, where a deeply mixed airmass
is forecast to be in place. Despite this deep mixing and somewhat
limited low-level moisture, the mid-level moisture associated with
the shortwave will allow for at least modest buoyancy (i.e. MLCAPE
over 500 J/kg). This should support storm maintenance off the
terrain, with a trend towards outflow-dominant bowing segments with
time. Primary severe risk is damaging gusts, including the potential
for gusts from 65 to 75 mph.

...Central Plains...
Moist southerly flow will help maintain moderate low-level moisture
through the NE Panhandle and into southwest SD amid the strong
heating and boundary-layer mixing expected this afternoon.
Additionally, this modest, but persistent, warm-air advection is
likely to force convective initiation this afternoon over the
western NE/SD border vicinity. Low-level southerly flow veering to
moderate northwesterlies aloft will support deep-layer shear of 40
to 50 kt, more than adequate for supercell development with any
mature convective. Any sustained supercells will be capable of
producing large hail (some 2+ inches) as they track
south-southeastward through the late afternoon into the evening.
Upscale growth into one or more bowing segments appears likely this
evening, with strong to severe gusts (65 to 75 mph) possible.

An isolated threat for severe hail/gusts may also exist
farther west/south across the CO Front Range to Raton Mesa vicinity.
Weaker buoyancy and deep-layer shear should keep any more organized
updrafts confined to the higher terrain and Foothills.

-- No other changes needed to the outlook with the text for the
additional areas appended from the 13Z Outlook below --

...Great Basin...
High-based thunderstorms should also develop this afternoon across
portions of northeast NV into northwest UT and southeast ID. While
low/mid-level winds and related thunderstorm organization will
likely be somewhat weaker/limited compared to areas farther north,
steep lapse rates and large DCAPE will support potential for strong
to severe outflow gusts as this convection spreads northeastward
into the early evening.

...South-Central/Coastal Texas into Southern Louisiana...
Ongoing thunderstorms across southern LA may pose a threat for gusty
winds this morning before they move offshore. Additional
thunderstorms may develop this afternoon from parts of south-central
TX towards the upper TX Coast, with isolated severe/damaging
downburst winds possible given ample moisture/instability forecast.
Weak deep-layer shear should limit the overall severe threat.

..Mosier/Chalmers.. 08/27/2026


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