182
ACUS03 KWNS 201917
SWODY3
SPC AC 201915
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0215 PM CDT THU AUG 20 2026
VALID 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN ROCKIES...AND THE OHIO VALLEY...
..SUMMARY
AFTERNOON STORMS MAY PRODUCE MARGINAL HAIL OR WIND GUSTS FROM THE
UPPER OHIO VALLEY TO THE LOWER GREAT LAKES, AND OVER PARTS OF THE
NORTHWEST ON SATURDAY.
..MIDWEST
AN UPPER TROUGH WILL DIG AND PIVOT SOUTHEAST ACROSS THE REGION ON
SATURDAY. AT THE SURFACE, A FRONT WILL EXTEND FROM LOWER MI TO
SOUTHERN IL AT THE START OF THE PERIOD, WITH THE BOUNDARY TRACKING
EAST/SOUTHEAST ACROSS THE OHIO VALLEY THROUGH EARLY SUNDAY. AHEAD OF
THE BOUNDARY, 60S F SURFACE DEWPOINTS BENEATH COOLER MIDLEVEL
TEMPERATURES WILL SUPPORT MODERATE DESTABILIZATION BY AFTERNOON.
WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE
SURFACE BOUNDARY AND SPREAD SOUTHEAST THROUGH EVENING. THIS ACTIVITY
WILL POSE A RISK FOR MARGINAL HAIL AND STRONG WIND GUSTS.
..NORTHERN ROCKIES
AN UPPER SHORTWAVE TROUGH WILL MOVE ACROSS THE PACIFIC NORTHWEST AND
NORTHERN ROCKIES ON SATURDAY. THIS WILL BRING ENHANCED SOUTHWESTERLY
FLOW AND COOLING ALOFT OVER MUCH OF THE REGION. STEEPENING MIDLEVEL
LAPSE RATES WILL SUPPORT WEAK DESTABILIZATION, AND ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED. A DEEPLY MIXED BOUNDARY
LAYER BENEATH STRENGTHENING FLOW ALOFT WILL SUPPORT STRONG OUTFLOW
WINDS WITH THIS ACTIVITY. SMALL HAIL COULD ALSO OCCUR WITH STRONGER
CELLS.
..LOWER MO VALLEY TO AR/MID-SOUTH
ENHANCED NORTHWESTERLY FLOW ALOFT WILL PERSIST OVER THE REGION ON
SATURDAY. A SURFACE FRONT WILL DROP SOUTHWARD ACROSS MO/IL INTO THE
OZARKS AND MID-SOUTH VICINITY. AHEAD OF THE FRONT, A SEASONALLY
MOIST AIRMASS WILL BE IN PLACE, AND MODERATE TO STRONG INSTABILITY
IS FORECAST. SOME FORECAST GUIDANCE SUGGESTS A REMNANT MCV OR
OUTFLOW FROM PRIOR CONVECTION COULD FOCUS THUNDERSTORM DEVELOP ALONG
THE SAGGING SURFACE FRONT. WHERE THE GREATEST COVERAGE OF
THUNDERSTORMS OCCURS REMAINS HIGHLY UNCERTAIN. IF CONFIDENCE
INCREASES IN SUBSEQUENT OUTLOOKS, WIND PROBABILITIES COULD BE NEEDED
FOR PORTIONS OF THE REGION.
..LEITMAN.. 08/20/2026
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