RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1109 AM CDT Sat Jun 20 2026
Valid 201630Z - 211200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS THIS AFTERNOON AND TONIGHT....
...SUMMARY...
Severe thunderstorms are likely across parts of the central Plains
mainly this afternoon and evening. Large to very large hail, severe
winds (some 75+ mph), and a few tornadoes are possible.
...Central Plains...
Water vapor imagery shows a shortwave trough over ID/UT tracking
eastward toward the central High Plains. Southerly/southeasterly
low-level winds ahead of this feature over parts of eastern
CO/western NE/KS will help to maintain a moist and moderately
unstable air mass across the region, especially as low clouds
continue to burn off and afternoon heating commences. Scattered
thunderstorm development is expected by mid-afternoon over central
WY down into central CO in favored terrain/convergence areas. This
activity will spread eastward into a progressively more
moist/unstable air mass and intensify into supercells. A corridor
of favorable vertical shear will develop later today from northeast
CO into southwest NE/northwest KS for isolated tornadoes.
Otherwise, very large hail and damaging winds will be the main
concerns. Activity is likely to organize upscale during the evening
and spread across KS with a damaging wind risk persisting much of
the night.
...Southeast...
A very moist and moderately unstable air mass is present again today
over much of the southeast US. Most CAM solutions suggest scattered
afternoon thunderstorms across this area, including along the FL
east coast. Dewpoints in the 70s and PWAT values around 2 inches,
coupled with strong daytime heating and steep low-level lapse rates
suggest a risk of locally gusty/damaging wind gusts in the most
intense cores.
..Hart/Moore.. 06/20/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1223 PM CDT Sat Jun 20 2026
Valid 211200Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS INTO THE OHIO VALLEY...
...SUMMARY...
Severe storms are possible along a frontal zone from the Ohio Valley
to the central High Plains from Sunday afternoon into night. Large
to very large hail, severe winds, and tornadoes (some of which could
be strong) will be possible.
...Synopsis...
A series of vorticity maxima, some with convective origins, will
translate east through the central Plains and OH Valley, along with
a belt of 40-50+ kt winds at 500 mb. In the lower levels, a
southwesterly low-level jet (LLJ) initially from the southern Plains
into the mid MO Valley Sunday morning is forecast to migrate east
into the mid MS and OH Valleys, immediately ahead of a surface low
tracking through the lower MO Valley into IL/IN. A cold front will
trail the surface low, likely extending southwest through the lower
MO Valley into southern KS or northern OK and the TX Panhandle by
mid to late afternoon.
...Missouri into the OH Valley...
Latest models remain consistent with previous runs in depicting one
or multiple MCSs ongoing at 12Z Sunday along the LLJ axis from
eastern KS into parts of northern and central MO. While the models
signal a general decrease in storm coverage through the morning, the
presence of modestly strong vertical shear suggests the potential
for isolated occurrences of damaging winds and perhaps some hail
across MO into western IL.
Renewed storm development is anticipated by afternoon from IL/IN in
the vicinity of a remnant MCV west/southwest along the trailing
outflow/warm frontal boundary to the primary surface low over the
lower MO Valley. Enhanced warm thermal and moisture fluxes occurring
along the LLJ are expected to support air mass recovery in the wake
of the early-day storms with moderate to potentially strong
instability forecast from the lower OH Valley into the Ozarks, south
of the composite boundary.
Forecast soundings and plan-view kinematic fields indicate
relatively strong low-level and deep-layer shear in the vicinity of
the composite boundary across portions of MO/IL/IN Sunday afternoon
into evening, where the highest probability of supercells and/or
bowing structures capable of all hazards (including strong
tornadoes) is expected to exist. However, as was alluded to in the
initial Day 2 discussion, and is still the case, there is
considerable latitudinal variability in the composite boundary
location. As such, uncertainty remains too high to delineate higher
severe-weather probabilities for this region.
...Central High Plains...
A trailing vorticity lobe and western extension of a 40-50 kt
mid-level jet maximum are expected to support weak cyclogenesis
along a front or trough pushing into the region from the west. Ahead
of that boundary, steep low/mid-level lapse rates and modest
boundary-layer moisture content are expected to yield moderate
afternoon instability amidst sufficiently strong deep-layer shear to
support supercell storm modes capable of large to very large hail.
Most recent model guidance has shifted the corridor of preferred
storm development and residence slightly east across portions of
western and central NE into northwest KS, and the severe-weather
probabilities have been adjusted accordingly. Storms may congeal
into clusters Sunday evening with the severe-weather threat
transitioning more to damaging winds.
...Southern Kansas and northern Oklahoma into the Ozark Plateau...
High-resolution model guidance suggests that a sub-synoptic-scale
surface low/frontal wave may evolve Sunday afternoon along the
trailing front. Enhanced convergence near and east of that feature
should be sufficient to overcome the cap and allow for isolated to
widely scattered storm development. The combination of moderate to
strong instability and around 40 kt of deep-layer shear will support
supercells as the initial storm mode with a risk for large to very
large hail. A largely parallel orientation of the deep shear vector
to the surface front suggests the potential for merging storms
within a few hours after initiation, with damaging wind potential
increasing at that time. Storms are expected to grow upscale into
one or multiple MCSs with at least an isolated damaging-wind threat
spreading south through the Ozark Plateau region Sunday night.
..Mead.. 06/20/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1105 AM CDT Sat Jun 20 2026
Valid 231200Z - 281200Z
CORRECTED FOR TYPO
...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 noting 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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