324
ACUS01 KWNS 120050
SWODY1
SPC AC 120048
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0748 PM CDT TUE AUG 11 2026
VALID 120100Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE DAKOTAS AND NORTHERN NEBRASKA...AND FROM NORTHERN ILLINOIS TO
WESTERN NORTH CAROLINA...
..SUMMARY
SEVERE STORMS POSING A RISK FOR LARGE HAIL AND DAMAGING WINDS ARE
POSSIBLE INTO TONIGHT FROM THE DAKOTAS INTO THE MIDWEST.
..IL TO WESTERN NC
A BOWING LINE OF STORMS FROM CENTRAL KY INTO NORTHEAST TN/WESTERN VA
WILL CONTINUE TO DEVELOP SOUTHEAST THE NEXT FEW HOURS. A DAMAGING
WIND RISK WILL CONTINUE WITH THIS ACTIVITY IN THE SHORT TERM.
HOWEVER, CONVECTION SHOULD BEGIN TO WANE WITH SOUTHEAST EXTENT INTO
THE APPALACHIANS AS INSTABILITY WANES AND LOSS OF DAYTIME HEATING
RESULTS IN A COOLING BOUNDARY LAYER. CONVECTION ACROSS KY AND
PERHAPS PORTIONS OF EASTERN TN MAY REMAIN STRONGER INTO THE EVENING
GIVEN THE LARGE RESERVOIR OF INSTABILITY AHEAD OF STORMS, BUT
OVERALL EXPECTED IS FOR A GRADUAL WEAKENING TREND. REFERENCE MCD
1939 FOR MORE SHORT TERM DETAILS.
OVERNIGHT, MOST CAMS GUIDANCE SUGGESTS CONVECTION WILL REDEVELOP
WITHIN A WARM ADVECTION REGIME ACROSS PARTS OF NORTHERN IL INTO IN
AND THE OHIO VALLEY. THE 00Z DVN AND ILX RAOBS DEPICT AN IMPRESSIVE
THERMODYNAMIC AND KINEMATIC ENVIRONMENT. MIDLEVEL LAPSE RATES NEAR 8
C/KM AMID 40 KT EFFECTIVE SHEAR AND MUCAPE NEAR 5000 J/KG WITH WEAK
INHIBITION SUGGESTS ANY STORMS DEVELOPING WITHIN THIS ENVIRONMENT
COULD BE SEVERE. CONVECTION MAY DEVELOP ALONG THE INSTABILITY
GRADIENT AND LARGE HAIL IS POSSIBLE. IF SUFFICIENT CLUSTERING
OCCURS, DAMAGING WIND ALSO COULD BE POSSIBLE. AS A RESULT, THE
SLIGHT (LEVEL 2 OF 5) RISK AS BEEN EXPANDED BACK TO THE NORTHWEST
ACROSS NORTHERN IL.
..DAKOTAS INTO IA
SUPERCELLS ACROSS THE WESTERN DAKOTAS AND FAR NORTHERN NE WILL
CONTINUE TO POSE A RISK FOR VERY LARGE HAIL AND DAMAGING GUSTS THE
NEXT FEW HOURS. SEE MCD 1938 FOR SHORT TERM INFORMATION ON SEVERE
RISK.
IT IS UNCERTAIN HOW CONVECTION WILL EVOLVE LONGER-TERM DURING THE
OVERNIGHT HOURS. SOME GUIDANCE SUGGESTS CLUSTERING WILL OCCUR AND AN
MCS COULD DEVELOP, MOVING EAST/SOUTHEAST ACROSS SD/NORTHERN NE AND
PERHAPS AS FAR EAST AS IA. AMPLE WEST/NORTHWESTERLY FLOW ALOFT IS IN
PLACE, ALONG WITH A VERY MOIST AIRMASS WITH STRONG TO EXTREME
INSTABILITY. IF SUFFICIENT CLUSTERING CAN OCCUR, MCS
DEVELOPMENT/MAINTENANCE SEEMS PLAUSIBLE. HAVE EXPANDED THE SLIGHT
(LEVEL 2 OF 5) RISK EASTWARD ACROSS SD/NE INTO WESTERN IA BORDER
VICINITY FOR THIS POSSIBILITY.
..LEITMAN.. 08/12/2026
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