RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Fri Mar 20 2026
Valid 201300Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER OHIO VALLEY INTO THE CENTRAL APPALACHIANS...
...SUMMARY...
Strong to locally severe thunderstorms are possible across parts of
the Upper Ohio Valley, mainly late this afternoon into the evening.
...Upper Ohio Valley into the Central Appalachians...
A prominent mid/upper-level high will remain centered over AZ and
northwest Mexico today, with upper troughing over FL and the western
Atlantic forecast to continue moving eastward. In between these
features, a low-amplitude, mid-level shortwave trough is forecast to
advance southeastward from Ontario and the Great Lakes to the upper
OH Valley and Mid-Atlantic by this evening. Strong northwesterly
mid/upper-level flow associated with this feature will support 40-50
kt of deep-layer shear and the conditional potential for updraft
organization with any thunderstorms that can develop. However,
low-level moisture will likely remain quite limited across the upper
OH Valley, with surface dewpoints currently in the 30s only modestly
increasing by late afternoon into the mid 40s to perhaps low 50s as
modest low-level warm/moist advection of a partially modified Gulf
airmass spreads northeastward from the lower/mid MS Valley.
Even with continued concerns about the modest thermodynamic
environment (MUCAPE generally less than 750 J/kg), there still
appears to be some chance for strong thunderstorm development late
this afternoon into the evening across parts of the upper OH Valley
into the central Appalachians along/ahead of a surface cold front.
Isolated hail and damaging winds may occur with the stronger cells
that can develop and be sustained, although confidence in the
overall coverage of strong to severe convection remains low. The
loss of daytime heating and even more limited low-level moisture
with eastward extent into the central Appalachians should
spatially/temporally confine the already marginal severe threat.
..Gleason/Kerr.. 03/20/2026
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