Day 2

Categorical Day 1 Outlook

Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.

Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.

Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.

000
ACUS01 KWNS 221940
SWODY1
SPC AC 221938

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0238 PM CDT Wed Sep 22 2021

Valid 222000Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
EASTERN OHIO...WESTERN PENNSYLVANIA...AND NORTHERN WEST VIRGINIA...

...SUMMARY...
The greatest potential for damaging to severe thunderstorm winds and
a few tornadoes today will be over parts of Ohio, West Virginia and
western Pennsylvania.

...20Z Update...

...Upper OH Valley...
Recent surface analysis places a deepen low near the OH/WV/PA border
intersection, along the leading edge of a cold front pushing
eastward across the OH Valley. Overall instability remains modest
ahead of the front, but still sufficient for updrafts deep enough to
produce lightning. Additionally, the clearing across southwest PA
has allowed temperatures to climb into the low 80s, fostering
locally higher buoyancy in this region. Vertical shear remains
strong and the threat for embedded bowing structures capable of
damaging wind gusts and a tornado or two is expected to persist
throughout the afternoon into the early evening. 

...VA and Carolinas...
As mentioned in recently issued MCD #1776, a couple damaging gusts
may accompany the stronger storms through the remainder of the
afternoon. However, any severe threat is expected to isolated and/or
brief given the limited vertical shear.

..Mosier.. 09/22/2021

.PREV DISCUSSION... /ISSUED 1107 AM CDT Wed Sep 22 2021/

...Upper OH Valley...
A deep upper trough is moving slowly eastward across parts of
IL/IN/KY today, with an associated surface cold front extending from
central OH southward into east TN and northern GA.  A pocket of
partly cloudy conditions has developed ahead of the front from
central WV into eastern OH and western PA.  Continued afternoon
heating/destabilization will yield MLCAPE values of 1000-1500 J/kg. 
A surface low along the front over OH will deepen today as it tracks
into western PA.  Backing/strengthening low-level winds ahead of the
low will enhance convergence and aid in the development of
thunderstorms along the cold front.  Shear profiles will be rather
strong, posing the risk of supercell and bowing structures capable
of damaging winds and a few tornadoes.  Storms should weaken by
early evening as they move into more stable air over central PA.

...VA and Carolinas...
The aforementioned surface cold front will move across the mountains
of western VA/NC this afternoon.  Warm and humid conditions ahead of
the front will result in thunderstorm development.  Low and
deep-layer wind fields in this region are weaker than farther north,
suggesting storms will be less organized.  Nevertheless, isolated
intense cells may develop, with locally damaging winds possible.

$$
        

Day 3

Day 4