908
ACUS02 KWNS 080555
SWODY2
SPC AC 080554
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT MON SEP 08 2025
VALID 091200Z - 101200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL AND SOUTHERN HIGH PLAINS....
..SUMMARY
ISOLATED SEVERE STORMS ARE POSSIBLE OVER THE CENTRAL AND SOUTHERN
HIGH PLAINS TUESDAY.
..SYNOPSIS
AMPLIFIED MID-LEVEL FLOW WILL BE IN PLACE OVER MUCH OF THE US
TUESDAY, AS A BROAD UPPER LOW CONTINUES TO DEEPEN OVER THE
NORTHWEST. TO THE EAST, SHORTWAVE RIDGING IS FORECAST TO INTENSIFY
OVER THE CENTRAL ROCKIES AND HIGH PLAINS, WHILE BROAD AND INCOHERENT
TROUGHING PERSIST OVER THE EASTERN HALF OF THE CONUS. SOUTHWESTERLY
MID-LEVEL FLOW WILL GRADUALLY INCREASE OVER THE CENTRAL HIGH PLAINS
AS A SERIES OF WEAK EMBEDDED PERTURBATIONS PASS THROUGH THE CREST OF
THE UPPER RIDGE. THIS WILL AIDE IN STRENGTHENING A LEE TROUGH,
SUPPORTING SOUTH/SOUTHEASTERLY LOW-LEVEL FLOW AND SOME SEVERE STORM
POTENTIAL.
..CENTRAL AND SOUTHERN HIGH PLAINS
AS THE MID-LEVEL RIDGE CONTINUES TO BUILD OVER THE ROCKIES AND
ADJACENT PLAINS, A LEE TROUGH IS EXPECTED TO SHARPEN FROM WESTERN SD
INTO THE TX PANHANDLE. CONTINUED LOW-LEVEL SOUTHERLY FLOW WILL
ADVECT SEASONABLY RICH MOISTURE ALONG AND EAST OF THIS FEATURE,
SUPPORTING DIURNAL DESTABILIZATION WITH 2000-2500 J/KG OF MLCAPE
AVAILABLE. HOWEVER, FORCING FOR ASCENT FROM SEVERAL WEAK
PERTURBATIONS PASSING THROUGH THE TOP OF THE RIDGE IS LIKELY TO
REMAIN NEBULOUS AND DISPLACED WESTWARD OF THE PRIMARY SURFACE TROUGH
AXIS. RESIDUAL CAPPING, AND THE LACK OF BROADER SYNOPTIC SUPPORT IS
EXPECTED TO LIMIT DIURNAL THUNDERSTORM DEVELOPMENT OVER THE PLAINS.
EVENTUALLY ISOLATED DEVELOPMENT IS EXPECTED ALONG THE LEE TROUGH BY
EARLY EVENING, AIDED BY AN INCREASE IN THE SOUTHERLY LOW-LEVEL JET.
IF THESE STORMS CAN BECOME SUSTAINED, MARGINAL SUPERCELL WIND
PROFILES WOULD SUPPORT A RISK FOR LARGE HAIL AND STRONG GUSTS FROM
WESTERN KS AND SOUTHEASTERN CO INTO THE OK/TX PANHANDLE VICINITY.
STILL, SUBSTANTIAL UNCERTAINTY REMAINS REGARDING THE COVERAGE OF ANY
STRONGER STORMS ABLE TO DEVELOP. HAVE INTRODUCED A 5% RISK FOR HAIL
AND WIND POTENTIAL.
TO THE WEST OF THE SURFACE TROUGH, STRONG HEATING AND WEAK ASCENT
SHOULD ALLOW ISOLATED TO WIDELY SCATTERED, LIKELY HIGH-BASED,
THUNDERSTORMS TO DEVELOP OVER THE HIGHER TERRAIN OF CO/WY AND
ADJACENT HIGH PLAINS TUESDAY AFTERNOON. STEEP LOW-LEVEL LAPSE RATES
COULD SUPPORT AN OCCASIONAL SEVERE GUST WITH THIS ACTIVITY, BUT
LIMITED BUOYANCY AND MODEST FLOW ALOFT SUGGEST LITTLE ORGANIZED
SEVERE THREAT.
..UPPER MIDWEST
A WEAK SURFACE BOUNDARY/COLD FRONT WILL EXTEND FROM EASTERN SD INTO
NORTHWESTERN IA AND SOUTH-CENTRAL MN TUESDAY. LOW-LEVEL WARM
ADVECTION ATOP THIS BOUNDARY IN A MODESTLY SHEARED AND WEAKLY
UNSTABLE ENVIRONMENT WILL SUPPORT PERIODS OF SHOWERS AND
THUNDERSTORMS AS THE FRONT SLOWLY SAGS SOUTHWARD. OVERALL SEVERE
POTENTIAL IS EXPECTED TO REMAIN LOW AS CONVECTION SHOULD REMAIN TO
THE COOL SIDE OF THE BOUNDARY AND LIKELY BE ELEVATED. BUT, A
STRONGER STORM OR TWO COULD DEVELOP AND PRODUCE SMALL HAIL OR
LOCALLY GUSTY WINDS OVER PORTIONS OF EASTERN SD AND WESTERN MN.
..LYONS.. 09/08/2025
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