420
ACUS03 KWNS 070730
SWODY3
SPC AC 070729
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT SUN SEP 07 2025
VALID 091200Z - 101200Z
..NO SEVERE THUNDERSTORM AREAS FORECAST
..SUMMARY
A FEW STRONG STORMS ARE POSSIBLE OVER THE CENTRAL PLAINS AND UPPER
MIDWEST TUESDAY, BUT OVERALL SEVERE POTENTIAL IS LOW.
..SYNOPSIS
A BROAD UPPER TROUGH ACROSS THE PACIFIC NORTHWEST IS FORECAST TO
INTENSIFY AS IT SHIFTS EASTWARD, IMPINGING ON THE WESTERN FLANK OF A
SHORTWAVE RIDGE CENTERED OVER THE ROCKIES. TO THE EAST, PERSISTENT
TROUGHING SHOULD REMAIN IN PLACE, WITH SURFACE HIGH PRESSURE
DOMINATING THE EASTERN HALF OF THE COUNTRY. AS SOUTHWESTERLY FLOW
ALOFT INCREASES OVER THE WESTERN US AND CENTRAL ROCKIES, A SUBTLE
SHORTWAVE TROUGH/VORT MAX WILL PASS OVER THE CREST OF THE RIDGE AND
INTO THE PLAINS TUESDAY AFTERNOON AND EVENING. THIS SHOULD AID IN
STRENGTHENING A LEE TROUGH OVER THE HIGH PLAINS, POTENTIALLY SERVING
AS A FOCUS FOR ISOLATED THUNDERSTORM DEVELOPMENT.
...CENTRAL HIGH PLAINS..
CONTINUED LOW-LEVEL SOUTHERLY FLOW WILL ADVECT RICHER SURFACE
MOISTURE NORTHWESTWARD ACROSS THE HIGH PLAINS BEGINNING EARLY
TUESDAY. AS DEWPOINTS INCREASE INTO THE LOW TO MID 60S F, STRONG
HEATING SHOULD SUPPORT ROBUST DESTABILIZATION ALONG AND EAST OF THE
LEE TROUGH. 1500-2500 J/KG OF MLCAPE WILL DEVELOP BENEATH
SUBSTANTIAL CAPPING AS MID-LEVEL HEIGHTS WILL LIKELY REMAIN NEUTRAL
THROUGH MUCH OF THE DAY. EVENTUALLY, WEAK ASCENT FROM THE EMBEDDED
SHORTWAVE TROUGH AND LOW-LEVEL UPSLOPE FLOW MAY ALLOW FOR ISOLATED
STORM DEVELOPMENT ALONG THE LEE TROUGH OVER THE CENTRAL HIGH PLAINS.
NORTHWESTERLY FLOW ALOFT WILL BE MARGINALLY SUPPORTIVE OF ORGANIZED
STORMS, INCLUDING THE POTENTIAL FOR SUPERCELLS. HOWEVER, GIVEN THE
CAPPING AND WEAK ASCENT, CONSIDERABLE UNCERTAINTY REMAINS REGARDING
STORM COVERAGE AND SEVERITY. WHILE SPORADIC HAIL AND SEVERE GUSTS
CANNOT BE RULED OUT, CONFIDENCE REMAINS TOO LOW FOR SEVERE
PROBABILITIES AT THIS TIME.
..NORTHERN PLAINS AND UPPER MIDWEST
A DIFFUSE FRONT WILL STALL ACROSS THE NORTHERN PLAINS/UPPER MIDWEST
EARLY TUESDAY BENEATH THE WESTERN EXTENSION OF THE BROAD EASTERN US
TROUGH. WEAK LOW-LEVEL WARM AIR ADVECTION MAY SUPPORT SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH MUCH OF TUESDAY NEAR THE FRONT.
THESE PARCELS ARE LIKELY TO BE ELEVATED ALONG AND NORTH OF THE FRONT
WITH MODEST BUOYANCY AND VERTICAL SHEAR EXPECTED TO LIMIT OVERALL
SEVERE POTENTIAL. STILL, A FEW STRONGER STORMS WITH SPORADIC HAIL
POTENTIAL MAY EVOLVE, THOUGH CONFIDENCE IN A SUSTAINED SEVERE RISK
IS LOW.
..LYONS.. 09/07/2025
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