907
ACUS02 KWNS 040506
SWODY2
SPC AC 040504
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1204 AM CDT FRI SEP 04 2026
VALID 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
APPALACHIANS TO COASTAL NORTH CAROLINA...
..SUMMARY
SEVERE THUNDERSTORMS CAPABLE OF DAMAGING GUSTS ARE POSSIBLE ACROSS
PORTIONS OF THE CENTRAL APPALACHIANS AND CAROLINAS ON SATURDAY
AFTERNOON AND EVENING. ISOLATED OCCURRENCES OF LARGE HAIL AND SEVERE
WIND GUSTS ALSO APPEAR POSSIBLE OVER PARTS OF THE NORTHERN PLAINS
AND VICINITY SATURDAY AFTERNOON INTO NIGHT.
..OHIO VALLEY TO SOUTHERN MID-ATLANTIC/CAROLINAS
AN UPPER SHORTWAVE DISTURBANCE WILL MIGRATE THROUGH NORTHWESTERLY
FLOW ALOFT, LEADING TO MODEST HEIGHT FALLS ACROSS THE REGION ON
SATURDAY. AS THIS OCCURS, MIDLEVEL NORTHWESTERLY FLOW WILL
STRENGTHEN, SUPPORTING EFFECTIVE SHEAR MAGNITUDES IN THE 25-35 KT
RANGE. AT THE SURFACE, A COLD FRONT WILL DEVELOP SOUTH ACROSS THE
MIDWEST AND MID-ATLANTIC AFTER 00Z. AHEAD OF THE FRONT, A VERY WARM
AND MOIST AIRMASS WILL FOSTER A CORRIDOR OF MODERATE TO STRONG
INSTABILITY.
FORECAST GUIDANCE VARIES WITH REGARDS TO POSSIBLE MORNING
CONVECTION, RESULTING IN SOME UNCERTAINTY IN THE FORECAST FOR
SATURDAY. EARLY CONVECTION COULD BE ONGOING ANYWHERE FROM THE LOWER
OHIO VALLEY TOWARD THE WV/VA MOUNTAINS AS REMNANTS FROM DAY 1
THUNDERSTORM ACTIVITY. WHETHER THIS EARLY DAY ACTIVITY WILL
DISSIPATE OR RE-INTENSIFY AS IT MOVES INTO THE MOIST AND
DESTABILIZING DOWNSTREAM AIRMASS IS UNCERTAIN. REGARDLESS, THE
OVERALL ENVIRONMENT WILL SUPPORT AFTERNOON AND EVENING THUNDERSTORM
ACTIVITY AHEAD OF THE SOUTHWARD-ADVANCING FRONT AND ALONG A SURFACE
TROUGH THROUGH THE PARTS OF THE VA/NC/SD PIEDMONT. ORGANIZED
CLUSTERS WILL MAINLY POSE A DAMAGING WIND RISK AS CONVECTION SPREADS
EAST/SOUTHEAST DURING THE AFTERNOON AND EVENING.
..NORTHERN/CENTRAL PLAINS VICINITY
SUBSTANTIAL UPPER RIDGING WILL BE CENTERED OVER THE PLAINS ON
SATURDAY. HOWEVER, MOST GUIDANCE DEPICTS ONE OF MORE SHORTWAVE
DISTURBANCES MIGRATING NORTHEAST FROM THE CENTRAL ROCKIES INTO THE
NE/SD VICINITY. ADDITIONALLY, CONVECTION COULD BE ONGOING AT THE
START OF THE PERIOD ACROSS THE MID-MO VALLEY. SOUTHEASTERLY
LOW-LEVEL FLOW WILL RESULT IN MODEST BOUNDARY LAYER MOISTURE ALONG A
SURFACE TROUGH ACROSS THE NORTHERN/CENTRAL HIGH PLAINS, WITH
INCREASING DEWPOINTS FURTHER EAST TOWARD THE MO RIVER ALONG A
SURFACE BOUNDARY. STEEP MIDLEVEL LAPSE RATES WILL SUPPORT MODEST
INSTABILITY ACROSS THE HIGH PLAINS, WITH MODERATE TO STRONG
INSTABILITY FURTHER EAST.
IF STORMS ARE OCCURRING AT THE BEGINNING OF THE PERIOD ACROSS THE MO
VALLEY, HAIL AND STRONG WIND GUSTS WILL BE POSSIBLE, WITH SOME
INTENSIFICATION POSSIBLE TOWARD MIDDAY/EARLY AFTERNOON WITHIN THE
VERY MOIST/UNSTABLE AND FAVORABLY SHEARED ENVIRONMENT. ADDITIONAL
WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE
SURFACE TROUGH OVER THE HIGH PLAINS DURING THE LATE
AFTERNOON/EVENING. THIS ACTIVITY COULD PRODUCE STRONG OUTFLOW WIND
GUSTS GIVEN A DEEPLY MIXED BOUNDARY LAYER AND MODEST SHEAR, ALONG
WITH ISOLATED LARGE HAIL.
..LEITMAN.. 09/04/2026
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