← Previous February 27, 2024 10:26 AM

ACUS01 KWNS 271628
SWODY1
SPC AC 271626

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1026 AM CST Tue Feb 27 2024

Valid 271630Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS EVENING
AND TONIGHT OVER PORTIONS OF THE LOWER AND MIDDLE OHIO VALLEY...AND
ACROSS A SMALL PART OF NORTHERN ILLINOIS AND SOUTHEAST WISCONSIN...

...SUMMARY...
Severe thunderstorms, associated with large hail, damaging gusts,
and tornadoes, some of which may be significant, will be possible
from late this afternoon into the overnight, across portions of the
Ohio Valley and southern Great Lakes.

...OH Valley...
A fast-moving southern-stream shortwave trough over the central
Plains will track eastward today and begin affecting parts of MO by
late afternoon or early evening.  Most 12z guidance suggests that at
least isolated thunderstorm development will begin around/after dusk
as the large-scale forcing overspreads the northern extent of
moist/unstable air mass from southwest MO into southern IL.  These
storms will intensify and track eastward overnight roughly along the
OH river, moving into parts of OH/WV/PA by early morning Wednesday. 
Initial storms may be discrete, with sufficient vertical shear for
supercells structures capable of all severe hazards.  As the night
progresses, activity will likely evolve into fast-moving bowing
structures with an enhanced risk of damaging wind gusts and a few
tornadoes.  A strong tornado or two cannot be ruled out.  Have added
an ENH risk area for this scenario overnight.

...IL/WI...
A compact surface low is forecast to deepen across eastern IA this
afternoon, with a narrow warm sector pulling northward into much of
northern IL.  Strong forcing near the low and along the associated
warm front will lead to intense thunderstorms across portions of
northern IL after 22z.  Forecast soundings show steep low and mid
level lapse rates and sufficient CAPE, along with strong low and
deep layer shear profiles.  This will be conducive to supercell
structures capable of very large hail and damaging winds.  There
remains uncertainty whether these storms will be in the warm-sector,
or will be undercut by nearby cold air.  Have upgraded a small part
of this area to ENH risk for hail, but there is also concern for
tornadoes if the activity remains surface-based.

..Hart/Bentley.. 02/27/2024

$$