ACUS01 KWNS 220552
SPC AC 220550
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Fri Oct 22 2021
Valid 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
FAR SOUTHEAST VIRGINIA...EASTERN NORTH CAROLINA...SOUTHEAST KANSAS
AND NORTHERN OKLAHOMA...
Thunderstorms associated with marginally severe wind gusts will be
possible in parts of far southeast Virginia and eastern North
Carolina today. Hail may also occur across parts of southern Kansas
and northern Oklahoma during the overnight period.
...Far Southeast Virginia/Eastern North Carolina...
An upper-level trough will move eastward into the Ohio and Tennessee
Valleys today with southwest mid-level flow remaining along the
eastern Seaboard. At the surface, a cold front will advance
southeastward across the eastern foothills of the Appalachians. A
moist airmass will be in place ahead of the front across much the
central and eastern Carolinas. Moderate instability is forecast to
develop this afternoon as surface temperature warm in the eastern
Carolinas. In addition to the instability, thunderstorms that form
just ahead of the front will have access to moderate deep-layer
shear and steep low-level lapse rates. For this reason, a marginal
wind-damage threat can be expected to develop, especially in areas
that heat up the most.
...Southeast Kansas/Northern Oklahoma...
An upper-level ridge will move eastward across the Rockies today as
west-northwest mid-level flow remains over much of the Great Plains.
Low-level moisture advection will take place across parts of the
southern and central Plains this afternoon and evening. The moisture
advection will continue into the overnight period as a low-level jet
develops across the southern Plains. The exit region of the
low-level jet should be in southeast Kansas by late evening, where
lift will be favorable for thunderstorms. The potential for
thunderstorm development should increase during the overnight period
as the low-level jet strengthens, but the storms will be elevated
due to a surface temperature inversion. The RAP is forecasting
MUCAPE to reach the 1000 to 2000 J/kg range in southern Kansas and
northern Oklahoma with the instability mostly above 800 mb. This
combined with steep mid-level lapse rates and 35 to 40 kt of
effective shear should be enough for hail with the stronger