RSS Mesoscale Discussions from Storm Prediction Center
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 AM CDT Mon May 11 2026
Valid 131200Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY AND CENTRAL APPALACHIANS...
...SUMMARY...
Isolated severe storms will be possible on Wednesday across the Ohio
Valley and central Appalachians.
...Ohio Valley/Central Appalachians...
An upper-level trough will move eastward across the Ohio and
Tennessee Valleys on Wednesday. At the surface, a low will move
eastward across the lower Great Lakes, as a cold front advances
east-southeastward through the Ohio and Tennessee Valleys. Ahead of
the front, surface dewpoints in the lower to mid 50s F will
contribute to weak destabilization by afternoon. MLCAPE near the
instability axis is forecast to peak around 500 J/kg with 0-6 km
shear in the 25 to 35 knot range. This should support a marginal
severe threat during the afternoon as low-level lapse rates become
steep. A few isolated severe wind gusts will be possible.
..Broyles.. 05/11/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0318 AM CDT Mon May 11 2026
Valid 141200Z - 191200Z
...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
At mid-levels, a shortwave ridge is forecast to pass eastward
through the north-central U.S. on Thursday. A shortwave trough is
forecast to move into the Great Plains, with moisture and
instability located in the central Plains. Although most of the
airmass is forecast to be capped during the day, a few storms with
an isolated severe threat will be possible in areas that heat up the
most.
On Friday, a mid-level ridge is forecast to move eastward across the
Great Plains, as a moisture and instability advects northeastward
into the lower to mid Missouri Valley. Isolated to scattered
thunderstorms will be possible within this airmass in the afternoon
and evening. Hail and isolated severe gusts would be the primary
threats.
By Saturday, a wide corridor of moderate instability is forecast to
be in place over the Great Plains. A shortwave trough is forecast to
move into the central U.S. during the afternoon. Ahead of the
shortwave, scattered thunderstorms will be possible from north Texas
northward into Nebraska. Along the western edge of the instability
corridor, steep mid-level lapse rates and moderate deep-layer shear
are forecast. The environment could support large hail, damaging
wind gusts and an isolated tornado threat in the southern and
central Plains where instability, shear and lift are forecast to
become maximized.
...Sunday/Day 7 and Monday/Day 8...
On Sunday, mid-level flow is forecast to be southwesterly over the
central U.S., as a shortwave trough moves into the Great Lakes.
Another shortwave trough is forecast to move into the northern High
Plains. Further south in the southern and central Plains, moderate
to strong instability is forecast to be in place by midday.
Thunderstorm development is expected over parts of this unstable
airmass in the afternoon and evening. Although uncertainty exists
concerning the location of the greatest severe threat, some
solutions suggest potential for a large complex of storms from
eastern Kansas into Missouri. At this time, too much uncertainty
exists for the addition of a severe threat area.
On Monday, a front is forecast to advance southeastward across the
central U.S. Ahead of this front, isolated severe storms will be
possible near an axis of instability in the afternoon and evening.
However, model spread is relatively large concerning the timing of
features at this extended range.
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