No watches are valid as of Fri Aug 28 20:01:02 UTC 2026.MD 2163 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN CAROLINAS INTO NORTHEAST GEORGIA
Mesoscale Discussion 2163
NWS Storm Prediction Center Norman OK
0135 PM CDT Fri Aug 28 2026
Areas affected...western Carolinas into northeast Georgia
Concerning...Severe potential...Watch unlikely
Valid 281835Z - 282100Z
Probability of Watch Issuance...5 percent
SUMMARY...Storms will increase in coverage this afternoon, with
locally strong to perhaps damaging gusts possible.
DISCUSSION...A weak wind shift and surface trough currently extend
from southern VA into the western Carolinas and northern GA, with
thunderstorms now forming within this zone. Gradual destabilization
has occurred with MLCAPE of 1500-2000 J/kg, and continued heating is
expected just east of the surface trough.
Lapse rate profiles are not particularly steep, with surface
temperatures mainly in the 80s F. However, minor cooling aloft has
occurred as southern parts of the upper trough graze the area.
Storms should generally increase in coverage through the afternoon
as they encounter the warming air mass to the east. Winds in the
lower levels will remain weak, as will forcing for ascent overall.
As such, most of these storms should continued to be short lived.
..Jewell/Mosier.. 08/28/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RAH...RNK...GSP...FFC...
LAT...LON 34558367 35758206 36038159 36338099 36408009 35967988
35398043 33608354 33638439 33968451 34558367
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
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
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 PM CDT Fri Aug 28 2026
Valid 282000Z - 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 GEORGIA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN MAINE...
...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.
...20z Update...
The previous forecast largely remains on track with only minor edits
required - primarily to the general thunder line to reflect recent
convective trends. Weak/poorly organized convection ongoing across
the Mid-Atlantic and portions of Maine should continue to pose a
localized severe threat (mainly damaging wind) through late
afternoon. See MCDs #2162 and #2163 for additional short-term
details. Transient downbursts have been noted across the greater
Houston, TX area over the past 1-2 hours as thunderstorms develop
along the sea breeze. While small swaths of damaging wind may occur
with the more intense downbursts, this threat is expected to remain
fairly transient given poor deep-layer wind shear across the region
(wind speeds are generally 15 knots or less through the column per
regional VWPs).
Across the Great Basin, slight expansions of the 5% wind
probabilities were made to better reflect trends in recent
time-lagged CAM guidance. Some of the more aggressive solutions -
notably recent runs of the RRFS - hint at one or more corridors of
higher severe wind potential across eastern WY into SD as high-based
convection encounters richer low-level moisture/buoyancy over the
Plains. However, these solutions are exhibiting a considerable warm
bias compared to current observations and suggest that any residual
inhibition should be mixed out by this point in the day. Latest GOES
imagery and regional 18z soundings both depict lingering inhibition,
which casts considerable uncertainty onto the accuracy of the more
aggressive solutions.
..Moore.. 08/28/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 28 2026/
...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.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1225 PM CDT Fri Aug 28 2026
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN GREAT BASIN AND NORTHERN PLAINS...
...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin and northern Rockies. Severe wind gusts
are the main threat. Scattered severe storms are also likely across
portions of the northern High Plains, with potential for large hail
and damaging wind.
...Synopsis...
The axis of the western US ridge will shift eastward centering
across the Midwest D2/Saturday as a mid-level low digs southward
from the Pacific Northwest. Strengthening southwesterly flow aloft
will overspread the region from the northern Great Basin into the
northern Rockies/Intermountain west. With the increase in mid-level
flow across the northern Rockies, lee troughing will increase across
the central/northern Plains, with a lee cyclone developing across
the western Dakotas.
...Northern Great Basin into the Northern Rockies...
Widely scattered thunderstorms are expected to develop within a
broad region of greater ascent across the Northern Great Basin into
the Northern Rockies. Moisture will be primarily mid-level, with
deeply mixed profiles, steep low to mid-level lapse rates, and
fairly large dew point spreads near the surface. Though boundary
layer moisture will be limited, steep lapse rates and heating will
support at least moderate instability by the afternoon. With 40-50
kt 500 mb flow aloft, sufficiently strong deep layer speed shear
will promote a few organized storms and transient supercells capable
of damaging wind and marginally severe hail.
...Northern High Plains...
Upslope flow near the surface low in the Dakotas should promote
development of thunderstorms near the Black Hills and across
portions of the high terrain in eastern Wyoming/southeastern
Montana. Strengthening southerly flow will bring moisture northward,
with moderate to strong instability developing by the afternoon
across the western/central Dakotas. Elongated and largely straight
hodographs and deep layer shear around 40 kts will support
supercells capable of large hail and damaging wind.
Across eastern Wyoming, there is low confidence in a more organized
cluster evolving through time and moving into northern Nebraska.
Recent CAM guidance suggests a more focused corridor of severe wind
potential. The Marginal Risk was expanded southward to account for
this potential.
..Thornton.. 08/28/2026
|
