RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sun May 17 12:06:02 UTC 2026.
No Mesoscale Discussions are in effect as of Sun May 17 12:06:02 UTC 2026.
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Sun May 17 2026
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
PLAINS INTO PORTIONS OF THE MIDWEST...OHIO VALLEY...AND NORTH TO THE
GREAT LAKES...
...SUMMARY...
Widely scattered severe thunderstorms will be possible along a cold
front extending from the Great Lakes into the portions of the
Midwest and south to the Southern Plains. Storms will pose a risk
for primarily damaging wind and hail.
...Synopsis...
A cold front will extend from the Great Lakes region to the Midwest
and south into the Southern Plains D3/Tuesday. The upper-level
trough will continue lifting north and east into the Great Lakes
through the period.
...Upper Midwest to the Great Lakes...
Some remnant elevated thunderstorm activity may be ongoing toward
the start of the period D3/Tuesday across the upper Midwest. This
may pose some potential for a few instances of severe hail.
Redevelopment of thunderstorms is likely along the front by the
afternoon. Sufficient deep layer shear around 20-30 kts and moderate
instability ahead of the front may support supercells initially
capable of large hail and perhaps a tornado. Linear forcing with the
cold front will likely lead to upscale growth and potential for
damaging wind downstream into the Ohio Valley through time.
...Oklahoma/Texas...
Trends continue for more progressive movement of the cold front
through Oklahoma/north Texas Tuesday morning. As a result,
probabilities were shifted eastward again with this update. Widely
scattered thunderstorm development is expected by the afternoon
across eastern Oklahoma into north Texas. Though the better
mid-level flow will be displaced to the north, steep low to
mid-level lapse rates remaining across this region will support
potential for damaging wind and large hail given moderate
instability ahead of the front.
..Thornton.. 05/17/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Sun May 17 2026
Valid 201200Z - 251200Z
...DISCUSSION...
... D4/Wednesday - D8/Sunday...
On D4/Wednesday and D5/Thursday, a cold front will move
southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon. However,
strongest upper-level flow becomes displaced to the north from the
better instability, which will reside along and south of the front
across the southeastern US. There will be some potential for high
based thunderstorm development within the upslope regime across New
Mexico into far western Texas D4/Wednesday, with potential for large
hail. Overall, there is low confidence in a widespread/organized
severe threat.
D5/Thursday through D8/Sunday, moist southerly return flow will
begin across the southern/central Plains into the weekend. It is
likely that the cold front will stall becoming a diffuse stationary
boundary extending across the southern Plains into the Southeast,
with thunderstorm activity along and south of the boundary each day.
Overall, forcing for ascent will remain limited with generally weak
flow and height rises across the Plains. Confidence in a more
focused corridor of severe weather threat remains low at this time.
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