451
ACUS02 KWNS 200541
SWODY2
SPC AC 200539

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1239 AM CDT Mon Jul 20 2026

Valid 211200Z - 221200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF SOUTHERN INDIANA...NORTHEAST KENTUCKY...SOUTHERN/EASTERN
OHIO...WEST VIRGINIA...NORTHERN VIRGINIA...MARYLAND...AND
PENNSYLVANIA...

...SUMMARY...
Numerous severe thunderstorms are expected across a broad region
from the Ohio Valley into the Mid-Atlantic and Northeast on Tuesday.
All severe hazards are possible, but swaths of damaging wind gusts
should be the primary severe risk Tuesday afternoon into the
nighttime hours.

...Ohio Valley to the Mid-Atlantic and Northeast...

An upper trough will be oriented over the region on Tuesday, with
several shortwave impulses migrating through the larger-scale
system. At the surface, low pressure will move across southern
Ontario into Quebec. A trailing cold front will move across much of
the Midwest through the period, becoming positioned from western PA
to TN and northern AR/OK by Wednesday morning. Ahead of the main
surface front, surface prefrontal troughing is expected to develop
across western/central NY into the Mid-Atlantic vicinity. Rich
boundary-layer moisture will overspread much of the area, with
dewpoints from the mid-60s to low 70s F commonplace. This will aid
in development of moderate to strong instability.

Deep-layer flow will be strong for this time of year, with 40-60 kt
flow at 500 mb, and 30-50 kt in the 850-700 mb layer. Forecast
soundings indicate supercell wind profiles with favorably curved
low-level hodographs becoming elongated above 2-3 km across much of
the region. Convective evolution remains a bit uncertain, but a mix
of supercells and one or more bowing linear segments are expected
across the Ohio Valley into the Mid-Atlantic. Significant severe (2+
inch hail, 65+ kt winds, etc) potential is unclear, and will largely
depend on storm mode and mesoscale evolution of convection.
Temperatures aloft are relatively warm, around -5 to -7 C at 500 mb,
and this may inhibit sig hail potential. Meanwhile, 65+ kt gusts
could occur if a well-organized bowing structure and stronger cold
pool can develop. Given warm/moist low-levels and limited low-level
lapse rates, confidence in this scenario is low. As a result, the
CIG 1 area from the prior Day 3 outlook has been removed for now.
Where supercells can be maintained, a risk for a few tornadoes also
is possible.

While details regarding storm mode and evolution remain somewhat
uncertain, the overall environment will support a severe risk across
a broad region on Tuesday/Tuesday evening. Swaths of damaging winds
still appear to be the greatest risk, though all hazards are
possible.

..Leitman.. 07/20/2026

$$