RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1147 AM CDT Fri Jun 26 2026
Valid 261630Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE HIGH
PLAINS TO OZARKS AND LOWER OHIO VALLEY...AS WELL AS PARTS OF NEW
ENGLAND...
...SUMMARY...
Scattered severe thunderstorm development is expected today,
particularly this afternoon into tonight across parts of the Ozark
Plateau to Lower Ohio Valley and across parts of the northern and
central High Plains to the Black Hills vicinity. Other severe storms
are expected across portions of New England.
...Ozarks and Lower Ohio Valley...
Multiple eastward-moving MCVs remain evident regionally in
observational data at midday, probably strongest across southeast
Missouri, but also the Oklahoma/Arkansas border vicinity and
northern Kentucky. A related observed enhancement to the
low/mid-level flow will persists from the Ozarks/Bootheel
east-northeastward parallel to the Ohio River, but cloud
cover/scattered precipitation remains fairly prevalent regionally as
well. Peripheral cloud breaks and insolation should allow for
gradual destabilization, particularly on the south/southwest fringes
of this early day activity. This should lead to severe storm
development into mid/late afternoon through the evening, potentially
including supercells given the flow enhancement. A couple of
tornadoes could occur aside from wind damage.
...High Plains...
A seasonably anomalous upper trough will continue to amplify and
spread eastward over the Pacific Northwest toward the Great Basin
and Intermountain West, with a lead disturbance ejecting
northeastward toward the northern High Plains. Pronounced lee
troughing is forecast with a surface low expected to evolve over
central and southeast Montana through tonight. A corridor of at
least weak to moderate boundary-layer destabilization is expected
across the High Plains. Strengthening large-scale ascent and ample
vertical shear downstream of the digging large-scale troughing will
favor organized severe thunderstorm development late this afternoon
through evening. Supercells and evolving organized clusters will
pose a risk for large hail and severe gusts, and perhaps a tornado.
Across the central into southern High Plains, isolated to widely
scattered storms will likely develop/mature and propagate east
during the evening. Hail and wind are the primary hazards with this
activity and this severe risk will probably linger into the late
evening.
...New England...
Have introduced a Slight Risk for portions of the region, primarily
focused near the advancing surface low/warm front. A shortwave
trough over Ontario/Lower Great Lakes will move east across New
England by this evening. Cloud cover, albeit abating this afternoon,
will limit the overall magnitude of destabilization, but upwards of
1000-1500 J/kg SBCAPE are forecast to develop along/south of a warm
front. Elongated hodographs beneath a 100+ kt 250-mb speed max will
aid in storm organization in the form of possibly a couple of
supercells and organized multicells. Isolated coverage of large hail
and damaging gusts are the primary risks with the stronger
thunderstorms, but the moist environment and low-level shear/SRH
could yield a tornado threat.
...Mid-Atlantic States to Carolinas...
The southern periphery of stronger mid to high-level westerly flow
is forecast across the region, atop northward-shifting low-level
moisture that is richest across the Carolinas into southern
Virginia, where near/above 70 F surface dewpoints are prevalent. The
overlap of moderate westerly flow and weak destabilization is
expected to support scattered thunderstorms capable of strong to
locally severe/damaging gusts (50-60 mph). Additional sea-breeze
influenced locally severe storms may occur across the coastal plain
of the Carolinas.
..Guyer/Supinie.. 06/26/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Fri Jun 26 2026
Valid 262000Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN/CENTRAL HIGH PLAINS...SOUTHERN PLAINS TO THE LOWER OHIO
VALLEY...AND PARTS OF NEW ENGLAND...
...SUMMARY...
Scattered severe thunderstorm development is expected today,
particularly this afternoon into tonight across parts of the
southern Plains to Lower Ohio Valley and across parts of the
northern and central High Plains to the Black Hills vicinity. Other
severe storms are expected across portions of New England.
...20Z Update...
The forecast remains on track, and only minor changes were made with
this update.
The SLGT risk in the central High Plains was expanded southeastward
from southeast CO into southwest KS and parts of the OK/TX
Panhandles. Guidance is in relatively good agreement, depicting
thunderstorms evolving off the Raton Mesa and tracking
east-southeastward along a gradient of rich boundary-layer
moisture/moderate surface-based buoyancy this evening/tonight. Aided
by 40 kt of effective shear and increasing low-level hodograph
curvature amid a strengthening nocturnal LLJ, supercell clusters
will pose a risk for severe gusts, large hail, and possibly a
tornado.
Farther east, a minor westward expansion of the SLGT risk was made
into north-central OK. Ample diurnal heating/destabilization of a
very moist air mas (middle/upper 70s dewpoints) is yielding strong
surface-based buoyancy along an east/west-oriented surface boundary.
Current thinking is that a few organized clusters/supercells
developing along the boundary will be capable of producing severe
wind gusts and large hail later this afternoon/evening.
..Weinman.. 06/26/2026
.PREV DISCUSSION... /ISSUED 1147 AM CDT Fri Jun 26 2026/
...Ozarks and Lower Ohio Valley...
Multiple eastward-moving MCVs remain evident regionally in
observational data at midday, probably strongest across southeast
Missouri, but also the Oklahoma/Arkansas border vicinity and
northern Kentucky. A related observed enhancement to the
low/mid-level flow will persists from the Ozarks/Bootheel
east-northeastward parallel to the Ohio River, but cloud
cover/scattered precipitation remains fairly prevalent regionally as
well. Peripheral cloud breaks and insolation should allow for
gradual destabilization, particularly on the south/southwest fringes
of this early day activity. This should lead to severe storm
development into mid/late afternoon through the evening, potentially
including supercells given the flow enhancement. A couple of
tornadoes could occur aside from wind damage.
...High Plains...
A seasonably anomalous upper trough will continue to amplify and
spread eastward over the Pacific Northwest toward the Great Basin
and Intermountain West, with a lead disturbance ejecting
northeastward toward the northern High Plains. Pronounced lee
troughing is forecast with a surface low expected to evolve over
central and southeast Montana through tonight. A corridor of at
least weak to moderate boundary-layer destabilization is expected
across the High Plains. Strengthening large-scale ascent and ample
vertical shear downstream of the digging large-scale troughing will
favor organized severe thunderstorm development late this afternoon
through evening. Supercells and evolving organized clusters will
pose a risk for large hail and severe gusts, and perhaps a tornado.
Across the central into southern High Plains, isolated to widely
scattered storms will likely develop/mature and propagate east
during the evening. Hail and wind are the primary hazards with this
activity and this severe risk will probably linger into the late
evening.
...New England...
Have introduced a Slight Risk for portions of the region, primarily
focused near the advancing surface low/warm front. A shortwave
trough over Ontario/Lower Great Lakes will move east across New
England by this evening. Cloud cover, albeit abating this afternoon,
will limit the overall magnitude of destabilization, but upwards of
1000-1500 J/kg SBCAPE are forecast to develop along/south of a warm
front. Elongated hodographs beneath a 100+ kt 250-mb speed max will
aid in storm organization in the form of possibly a couple of
supercells and organized multicells. Isolated coverage of large hail
and damaging gusts are the primary risks with the stronger
thunderstorms, but the moist environment and low-level shear/SRH
could yield a tornado threat.
...Mid-Atlantic States to Carolinas...
The southern periphery of stronger mid to high-level westerly flow
is forecast across the region, atop northward-shifting low-level
moisture that is richest across the Carolinas into southern
Virginia, where near/above 70 F surface dewpoints are prevalent. The
overlap of moderate westerly flow and weak destabilization is
expected to support scattered thunderstorms capable of strong to
locally severe/damaging gusts (50-60 mph). Additional sea-breeze
influenced locally severe storms may occur across the coastal plain
of the Carolinas.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 PM CDT Fri Jun 26 2026
Valid 271200Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST
VA AND EASTERN NC...
...SUMMARY...
Severe storms are likely across portions of eastern Montana and
western/central North Dakota on Saturday. Severe storms will also be
possible from the Mid-Mississippi Valley to Virginia and the
Carolinas, as well as portions of the southern High Plains.
...Synopsis...
An upper low and attendant large-scale upper trough will persist
across the western U.S. on Saturday. Further east, upper ridging
over the Plains is forecast to shift east toward the Upper Midwest
and Mid-MS Valley by Sunday morning. Quasi-zonal/weak upper
troughing is expected to persist across the eastern U.S. Within this
large-scale regime, several shortwave impulses and embedded MCVs are
expected to drive severe thunderstorm potential across multiple
areas on Saturday. A lead upper shortwave trough is expected to
eject from the eastern Great Basin through the northern High Plains.
A series of MCVs will move from the Ozark Plateau to the OH/TN
Valleys, while another MCV and/or surface trough impacts
thunderstorm potential across the Mid-Atlantic/Piedmont. Finally,
another upper shortwave impulse could emerge across the central
Plains into the Mid-MO/Mid-MS Valleys.
...Northern Rockies into the Northern Plains...
A midlevel jet streak will overspread parts of the Great Basin into
the northern Plains, characterized by 50-60 kt southwesterly 500 mb
flow. Cooling aloft is also forecast and will result in a plume of
steep midlevel lapse rates. Surface low pressure is forecast to
deepen across northeast WY/western SD through evening. This will
support northward transport of low to mid 60s F dewpoints into
eastern MT/ND/SD. This will result in a narrow corridor of moderate
to strong instability. Capping will increase with eastward extent as
a result of midlevel height rises/warming aloft, which should
confine the eastward extent of severe potential.
As large-scale ascent increasing during the afternoon, convection is
expected to develop across the higher terrain of northern UT/ID into
WY. This initial activity will pose a risk for strong wind gusts and
isolated hail given strong deep-layer flow, steep midlevel lapse
rates, and a well mixed boundary layer. Additional convection is
expected to develop near the Big Horns and Beartooth/Absaroka
ranges. As this activity develops northeast into better low-level
moisture and strong instability, large to very large hail potential
will increase. With time during the evening, a southerly low-level
jet will increase across the Dakotas. Upscale growth is possible as
convection moves toward the terminus of the low-level jet and as
sufficient clustering/cold pool development occurs. If this
convective evolution unfolds, a swath of damaging wind gusts will be
possible, mainly across eastern MT into western ND.
...Mid-Atlantic...
Ongoing convection and cloudiness will likely hinder daytime
destabilization. Nevertheless, several shortwave impulses will move
across the region along with 25-30 kt westerly midlevel flow.
Isolated strong storms may produce gusty winds. The Slight risk
(level 2 of 5) has been confined to areas nearer the coast where
instability will be greatest.
...Southern High Plains...
A surface trough/dryline will extend south/southwest from western KS
to southwest TX. A moist airmass will exist east of this boundary
with hot temperatures forecast along and just behind the boundary.
Moderate to strong destabilization will occur near the boundary in a
narrow corridor, confined by stronger capping to the east across
much of OK/KS/central TX. However, isolated to widely scattered
storms are expected to develop during peak heating to early evening.
Vertically veering wind profiles with up to 25 kt effective shear
magnitudes suggest organized updrafts and high-based transient
supercell structures are possible. Given a deeply mixed boundary
layer, strong gusts will be possible. Organized updrafts that can be
maintained also will pose a risk of large hail given very steep
midlevel lapse rates and somewhat elongated hodographs.
...Ozarks to TN Valley vicinity...
Storms are forecast to be ongoing Saturday morning across southwest
MO. This activity could pose a marginal wind/hail risk initially.
Additional development is expected from southern IL/southeast MO
into KY/TN by late morning and spread east through the afternoon as
an MCV moves across the region. While deep layer flow will not be
impressive, the MCV could locally enhanced vertical shear.
Thunderstorm clusters will mainly pose a risk for damaging winds as
they track across moisture-rich and moderately unstable airmass.
...Northeast CO/Western NE into central SD...
Convection may develop during the late afternoon along the surface
trough/dryline. Rich boundary layer moisture beneath steep lapse
rates will support strong destabilization. This corridor will remain
rather confined given rising midlevel heights and capping to the
east. Any storms that develop will have potential for strong outflow
gusts and large hail.
...Mid-MO Valley vicinity...
It is uncertain if convection will develop across this area, or if
it does - will it be surface-based, resulting in a rather
conditional severe risk. If storms can develop, an all-hazards
severe risk would be possible given a surface warm front lifting
north across the region amid ample moisture/instability and
supercell wind profiles. Given the conditional nature of the risk,
particularly due to capping, will maintain low severe probabilities.
..Leitman.. 06/26/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0216 PM CDT Fri Jun 26 2026
Valid 281200Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
NORTH DAKOTA AND THE UPPER MIDWEST...
...SUMMARY...
Severe thunderstorms are possible from the northern Plains into
parts of the Upper Midwest on Sunday. Large hail and severe winds
are the primary hazards.
...Synopsis...
The western U.S. upper trough will deepen and persist over that
region on Sunday. Meanwhile, upper ridging will intensify over the
Midwest into the South, while a shortwave upper trough moves from
the Ohio Valley to the southern Mid-Atlantic region. At the surface,
some uncertainty persists with regards to the location of lee
surface low development in the central or northern Plains. The NAM
appears to be an outlier compared to the ECMWF/GFS and the AI
versions thereof. This will be important for where the best corridor
of severe thunderstorm potential develops on Sunday
afternoon/evening. Further east, a surface front will sag southward
across the Upper OH Valley and portions of the Mid-Atlantic. Between
these surface boundaries, a seasonally very moist airmass will exist
across at least eastern portions of the Plains to the MS Valley and
the southern Mid-Atlantic.
...Northern Plains/Upper Midwest vicinity...
The forecast for Sunday is highly uncertain. Forecast guidance
suggests a shortwave impulse and/or MCV will move across northern MN
during the afternoon/evening. This area will be beneath the upper
ridge axis and could be capped. However, a very moist airmass will
be in place beneath steep midlevel lapse rates. Furthermore, a
strong southerly low-level jet is expected to focus from the central
Plains to the Upper MS Valley during the evening/nighttime hours. If
storms can develop and become near-surface based, potential for
damaging wind gusts and large hail will be possible. This scenario
is generally supported by the RRFS and GSL MPAS, though
location/timing varies.
Forecast guidance develops additional areas of convection across
portions of western NE/central SD into ND on the western periphery
of stronger capping and near the surface trough/dryline within the
gradient of stronger instability. This scenario is uncertain, both
regarding storm development, and if storms occur, whether or not
they will be surface-based. However, if storms do develop, an
intense low-level jet within the strongly unstable airmass during
the evening/overnight hours could support damaging wind potential.
The Marginal risk (level 1 of 5) has been adjusted to reflect this
conditional risk.
...Southern Mid-Atlantic...
Forecast guidance suggests an MCV will move across the central
Appalachians into parts of VA/NC on Sunday. Deep-layer flow is not
expected to be particularly strong, but this feature could locally
enhanced vertical shear, with some guidance showing effective shear
magnitudes up to 25 kt are possible. A seasonally very moist airmass
will reside east of the higher terrain across southeast VA into the
eastern Carolinas, supporting moderate destabilization as strong
daytime heating occurs. Thunderstorms will pose an isolated damaging
wind risk into early evening.
..Leitman.. 06/26/2026
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