RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Sat Jun 20 2026
Valid 201200Z - 211200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN
COLORADO INTO WESTERN/CENTRAL KANSAS AND SOUTHERN NEBRASKA...
...SUMMARY...
Severe thunderstorms are likely across portions of the central
Plains vicinity this afternoon and evening. Large to very large
hail, severe winds (some 75+ mph), and tornadoes are possible.
...Central Plains...
A low-amplitude mid/upper-level shortwave trough will move from the
Intermountain West toward the central/northern High Plains through
the period. In response to this system, a lee cyclone is forecast to
deepen across eastern CO. A surface front initially draped from
eastern CO into KS will move northward through the day, with its
northward extent influenced by morning elevated convection that may
persist through much of the day across parts of central NE. Rich
low-level moisture will return in tandem with the front, with
low/mid 60s F dewpoints reaching into parts of southern NE and
northeast CO, and upper 60s to low 70s F dewpoints spreading into
parts of central/southeast KS.
Relatively steep midlevel lapse rates spreading atop the returning
moisture will result in moderate to strong destabilization, as
MLCAPE increases to near/above 2000 J/kg across parts of the central
High Plains. Scattered thunderstorm development is expected by late
afternoon from southeast WY and the NE Panhandle into eastern CO,
with at least isolated storms possible farther east, along and just
north of the surface front. Veering wind profiles and effective
shear of 40+ kt will be favorable for organized storms, including
supercells.
A threat for large to very large hail and localized severe gusts
will accompany initial supercell development. Some tornado threat
could also evolve, especially with any supercells near the front
that move into an environment of richer moisture and stronger
low-level shear (associated with a modest nocturnal low-level jet)
during the evening. A tendency toward upscale growth is expected
with time along and north of the surface front, resulting in an
increasing severe-wind threat, with gusts above 75 mph possible.
Some damaging-wind and brief-tornado threat could continue through
the end of the period into east-central/southeast KS, where MLCINH
will remain minimal due to very rich low-level moisture.
Only minor adjustments have been made to the Enhanced Risk, though
more substantial changes may eventually be needed, depending on the
influence of early-day convection across parts of the threat area.
...Northern UT/southeast ID into western/central WY...
As a mid/upper-level shortwave trough overspreads the region during
the afternoon, scattered high-based thunderstorm development is
expected from northeast UT/southeast ID into western WY. Isolated
downbursts will be possible with initial development, and some
outflow aggregation could result in localized strong to severe wind
swaths from late afternoon into early evening, as convection spreads
eastward.
...Parts of TX into the Southeast and Florida...
Scattered to widespread convection is again expected within a very
moist (PW near/above 2 inches) environment from central/eastern TX
into parts of the Southeast and Florida. Localized wet microbursts
will again be possible, though deep-layer shear will generally be
weak. Organized severe potential appears too nebulous to add wind
probabilities at this time. A Level-1/Marginal Risk may eventually
be needed for parts of the region, if trends support any mesoscale
corridors of somewhat more organized threat.
...Western PA...
Relatively low-topped convection may develop across parts of western
PA and vicinity this afternoon, within a broad west-northwesterly
flow regime. Buoyancy will remain weak, but modestly enhanced flow
and steep low-level lapse rates could support localized strong
gusts. The magnitude of the threat appears too limited for wind
probabilities at this time.
..Dean/Squitieri.. 06/20/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Sat Jun 20 2026
Valid 211200Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS TO PARTS OF THE MID-MISSISSIPPI VALLEY....
...SUMMARY...
Severe storms are possible along a frontal zone from the
Mid-Mississippi Valley to the central High Plains on Sunday. Large
hail, severe winds, and tornadoes will be possible.
...Synopsis...
A series of mid-level shortwave troughs will move through the
central portion of the CONUS along a surface frontal zone. The
primary surface low is expected to settle somewhere near the Texas
Panhandle on Sunday with a weaker, perhaps convectively enhanced,
surface low across the Midwest.
...Ozarks into the Lower Ohio River Valley...
An expansive MCS will likely be present across eastern Kansas and
into Missouri on Sunday morning. This MCS will continue east through
the day and eventually into the Ohio Valley by the afternoon. An
outflow boundary will likely be left in the wake of this MCS across
Missouri and southern Illinois during the afternoon. The degree of
airmass recovery within this region remains uncertain. Some guidance
shows a secondary MCS moving into northeast Oklahoma and northern
Arkansas, which may have implications on the upstream EML and the
potential for clearing/recovery in the wake of the morning MCS.
However, other guidance shows an EML advecting into the region and
aiding in recovery during the afternoon/evening. A localized
corridor with greater tornado threat likely exists along this
boundary from eastern Missouri into southern Illinois and perhaps
southwest Indiana, but too much uncertainty from prior storms
precludes any higher tornado probabilities at this time.
...Central High Plains Vicinity...
Storms are forecast to develop within the upslope flow across
western Kansas by mid-afternoon. Easterly surface flow, combined
with strengthening flow aloft (in excess of 50 knots above 400mb)
will support supercell structures and the potential for large to
very large hail. Storm motions will be relatively slow and thus, the
storms likely won't make it that far east due to increasing
inhibition with eastward extent. However, some guidance, most
notably the 00Z HRW-NSSL WRF show some elevated supercells farther
north into Nebraska toward the end of the period. If this persists
in later guidance, an eventual eastward expansion of the Slight Risk
may be needed.
...Southern Kansas and Northern Oklahoma...
Storms will continue to build westward during the day into eastern
and perhaps central Kansas, and will congeal and shift southward
through the evening. Overnight, as the low-level jet strengthens,
expect storms to develop in an area with moderate to strong
instability. These storms may pose some initial hail threat before
growing upscale into an MCS with a wind threat across southern
Kansas and northern Oklahoma during the overnight hours.
..Bentley.. 06/20/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0238 AM CDT Sat Jun 20 2026
Valid 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS AND SOUTHERN PLAINS TO THE MID-SOUTH AND INTO THE
CAROLINAS AND MID-ATLANTIC....
CORRECTED FOR CAPITALIZATION IN THE SUMMARY
...SUMMARY...
Isolated strong to severe storms are expected along a frontal zone
that extends from the mid-Atlantic to the Mid-South and southern
Plains and into the central High Plains on Monday.
...Synopsis...
A flat ridge is forecast across the western CONUS with broad
cyclonic flow from the southern Plains to the Mid-Atlantic. Within
this zone, several embedded mid-level shortwave troughs are
expected, the strongest of which will move from the Ohio Valley to
the Mid-Atlantic during the day Monday. A weak surface low will
likely be associated with this lead shortwave trough with an
additional lee trough, likely across the southern High Plains. A
frontal zone will extend between these 2 features and act as the
primary focus for storm development through the period on Monday.
...Central/southern Plains...
A MCS should be ongoing at the beginning of the period across parts
of Oklahoma on the nose of the low-level jet. An outflow boundary
will likely extend westward from this MCS into parts of Northwest
Texas and into the Texas Panhandle.
Very strong to extreme instability is forecast across the southern
Plains on Monday with dewpoints in the mid to upper 70s and steep
lapse rates. Model guidance is consistent showing a weak mid-level
shortwave trough emerging across the southern Plains by 00Z Tuesday
with 30 to 35 knots of mid-level flow. The combination of this
shortwave trough and the potential for an outflow boundary
intersecting the dryline may result in a more focused area of severe
potential Monday afternoon/evening. However, due to the mesoscale
nature of this potential, confidence is not high enough to add a
Slight Risk at this time.
...Mid South...
Moderate to strong instability is forecast to develop ahead of the
MCS across Oklahoma and Arkansas Monday morning. Given the very
moist airmass, inhibition should be eroded by mid-day. Therefore,
reintensification of the morning MCS or additional development to
the east along the front (likely a combination of both) is expected
from near the Red River to northern Mississippi. This strong
instability, combined with modest shear, will support some damaging
wind threat with a southeastward moving cluster of storms Monday
afternoon/evening.
...Carolinas to the Mid-Atlantic...
A moist airmass will move into the Carolinas and Mid-Atlantic on
Monday ahead of an eastward moving cold front. Mid-level lapse rates
will be weak which will limit overall instability, but moderate
shear and sufficient instability, combined with steep low-level
lapse rates will support some damaging wind threat Monday
afternoon/evening. In addition, a smaller area of greater low-level
shear may exist closer to the surface low across northern Virginia
and vicinity, which could have a localized region of greater tornado
threat.
..Bentley.. 06/20/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0330 AM CDT Sat Jun 20 2026
Valid 231200Z - 281200Z
...DISCUSSION...
An extended period of moderate northwesterly flow across the High
Plains will lead to severe weather potential across the central High
Plains. Upslope flow amid 30 to 50 knots mid-level winds should
result in a severe weather environment, potentially on Tuesday, and
particularly Wednesday and Thursday. The front will shift based on
small-scale embedded shortwave disturbances and the prior day's
convection, which will shift the location of the unstable warm
sector. This results in uncertainty regarding the location of the
threat for each day. This will continue to be monitored for
potential areas to be added later.
Ridging will slide east across the Rockies and into the Plains by
next weekend. Some severe weather threat may exist through this time
as multiple embedded shortwave troughs will be within this region as
instability increases across the Plains.
While it is mostly beyond Day 8, it is worth nothing that
deterministic, ensemble, and AI guidance all indicate a strong jet
streak and mid-level trough traversing the Rockies toward the end of
next weekend and into early next week. A strong lee cyclone would
accompany this with strong instability across the Plains. There is
still uncertainty with the timing and location of the trough, but
given the agreement in this general pattern change, a substantial
severe weather threat seems possible by the end of next weekend and
early into the following week across portions of the
central/northern Plains into the Upper Midwest.
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