Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Sun Mar 22 2026
Valid 221300Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY AND MID-ATLANTIC...
...SUMMARY...
Scattered severe thunderstorms appear likely this afternoon and
evening across parts of the Ohio Valley into the Mid-Atlantic. Large
to very large hail and damaging winds should be the main threats,
but a tornado or two may also occur.
...Ohio Valley into the Mid-Atlantic...
Gradual amplification of mid/upper-level troughing will occur today
as a shortwave trough moves quickly eastward across the northern
Plains, Upper Midwest, and Great Lakes through the period. A belt of
enhanced mid/upper-level west-southwesterly flow will overspread
much of the OH Valley and northern Mid-Atlantic today, while
modest/shallow low-level moisture streams northward across these
regions ahead of a surface cold front. This front is expected to sag
slowly south-southeastward this afternoon and evening across the OH
Valley into PA, and will likely serve as a focus for strong to
severe convection later today.
The NAM remains on the aggressive side of short-term guidance with
the degree of low-level moisture present ahead of the front by mid
afternoon, with consensus of most other guidance suggesting that the
boundary layer will become well mixed with robust daytime heating
(surface dewpoints generally in the mid 50s). Even so, cool
mid-level temperatures and steepened lapse rates aloft will
contribute to the development of weak to moderate instability
(MLCAPE around 500-1500 J/kg in a narrow zone along/ahead of the
cold front). Favorable deep-layer shear (40-50+ kt) will foster
updraft organization, including the potential for supercells.
Current expectations are for robust thunderstorms to develop by
19-22Z across eastern OH into western/central PA near the front, as
MLCIN should become minimal with northeastward extent across the
upper OH Valley by this time frame. This initially discrete
convection should quickly acquire supercell characteristics, and
large to very large hail (up to 1.5-2.5 inches in diameter) appears
to be the main threat given relatively long/straight hodographs at
mid/upper levels and the presence of steepened mid-level lapse
rates. This activity may tend to grow upscale as it moves
east-southeastward across PA through the evening, with an increasing
threat for scattered severe/damaging winds where low-level lapse
rates can become steepened with daytime heating.
Additional thunderstorms should eventually develop this evening
farther to the southwest across much of the OH Valley as the front
continues shifting south-southeastward. Much of this convection may
tend to become elevated along/north of the undercutting cold front.
But, it should still pose a threat for large hail, as moderate
MUCAPE and strong deep-layer shear will favor supercell structures
initially. The Marginal and Slight Risks have been adjusted/shifted
northward a little to account for where robust convection will
likely develop this afternoon/evening. The tornado potential today
remains uncertain, as expectations for a well-mixed boundary layer
across the warm sector this afternoon will likely promote large
surface temperature-dewpoint spreads and high LCLs. Still, a tornado
or two appears possible along/ahead of the front, assuming
convection can remain surface based.
..Gleason/Kerr.. 03/22/2026
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/TRdfXf
