794
ACUS02 KWNS 101736
SWODY2
SPC AC 101734
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1234 PM CDT WED SEP 10 2025
VALID 111200Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
ROCKIES TO THE NORTHERN PLAINS....
..SUMMARY
ISOLATED STRONG TO SEVERE THUNDERSTORMS WITH HAIL AND SEVERE WIND
POTENTIAL ARE POSSIBLE ACROSS PORTIONS OF THE ROCKIES,
CENTRAL/NORTHERN HIGH PLAINS INTO THE DAKOTAS AND NORTHERN MINNESOTA
ON THURSDAY.
..SYNOPSIS
ON THURSDAY, A LARGE TROUGH WILL BE PRESENT ACROSS THE WESTERN CONUS
WITH A STRONG RIDGE ACROSS THE PLAINS AND TROUGHING ACROSS THE EAST.
THIS PATTERN WILL SHIFT SLOWLY EAST THROUGH THE DAY. SURFACE HIGH
PRESSURE WILL DOMINATE MUCH OF THE EASTERN CONUS WITH LEE TROUGHING
IN THE CENTRAL AND NORTHERN HIGH PLAINS.
...EASTERN MONTANA/NORTHERN WYOMING INTO THE DAKOTAS AND NORTHERN
MINNESOTA...
A CLUSTER OF STORMS MAY BE ONGOING ACROSS NORTHERN NORTH DAKOTA AT
THE START OF THE PERIOD. A MODERATE LOW-LEVEL JET IS FORECAST TO
MAINTAIN INTENSITY (AND PERHAPS STRENGTHEN SOMEWHAT) DURING THE DAY.
THIS MAY RESULT IN MAINTENANCE OF THIS CLUSTER AND RESTRENGTHENING
DURING THE AFTERNOON ACROSS SOUTHERN CANADA AND PERHAPS INTO
NORTHERN NORTH DAKOTA AND NORTHERN MINNESOTA. MODERATE INSTABILITY
AND MODERATE SHEAR, COMBINED WITH STEEP LAPSE RATES, WILL SUPPORT
THE POTENTIAL FOR LARGE HAIL AND DAMAGING WIND GUSTS AS THESE STORMS
MOVE EAST.
COOLING TEMPERATURES ALOFT AND STEEP LAPSE RATES WILL LEAD TO
SCATTERED TO WIDESPREAD THUNDERSTORM DEVELOPMENT ACROSS MUCH OF THE
HIGHER TERRAIN ACROSS WYOMING AND MONTANA. MODEST DEEP-LAYER SHEAR
AND A RELATIVELY DRY PROFILE WILL SUPPORT THE POTENTIAL FOR SOME
ORGANIZED STORMS INCLUDING SUPERCELLS. THESE STORMS MAY PRODUCE
ISOLATED LARGE HAIL AND SEVERE WIND GUSTS.
A MORE CONDITIONAL SEVERE ENVIRONMENT WILL BE PRESENT ACROSS EASTERN
WYOMING/MONTANA AND INTO THE WESTERN DAKOTAS. STRONGER INSTABILITY
(2000 TO 3000 J/KG MLCAPE) IS FORECAST ACROSS THE REGION, BUT ONLY
WEAK HEIGHT FALLS WILL BE PRESENT WITH AT LEAST SOME RESIDUAL
CAPPING FROM MOST FORECAST SOUNDINGS. SOME WEAK
CONVERGENCE/CONFLUENCE WILL BE PRESENT ALONG THE LEE TROUGH/DRYLINE
WHICH COULD INITIATE A FEW STORMS. IF STORM FORM WITHIN THIS REGION,
MODERATE DEEP-LAYER SHEAR COULD SUPPORT SUPERCELLS CAPABLE OF LARGE
HAIL AND SEVERE WIND GUSTS. IF THIS SCENARIO APPEARS MORE LIKELY, A
SLIGHT RISK MAY BE NEEDED IN LATER OUTLOOKS, PARTICULARLY ACROSS
EASTERN MONTANA AND WESTERN NORTH DAKOTA.
..CENTRAL ROCKIES
MODERATE TO STRONG SHEAR WILL BE PRESENT ACROSS THE ROCKIES AS A 45
TO 60 KNOT MID-LEVEL JET STREAK OVERSPREADS THE REGION. WEAK HEIGHT
FALLS, TERRAIN DRIVEN CIRCULATIONS, AND WEAK DIFFLUENCE ALOFT WILL
COMBINE FOR WIDESPREAD THUNDERSTORM DEVELOPMENT THURSDAY
AFTERNOON/EVENING. RAP FORECAST SOUNDINGS SHOW 500 TO 750 J/KG
MLCAPE AND 1000-1300 J/KG MUCAPE AT KGJT WHICH IS WELL ABOVE THE
90TH PERCENTILE AND NEAR THE ALL TIME MAXIMUM FOR MID-SEPTEMBER IN
GJT BASED ON SPC SOUNDING CLIMATOLOGY. THIS ABNORMALLY UNSTABLE
AIRMASS COMBINED WITH MODERATE SHEAR WILL RESULT IN AN ENVIRONMENT
CAPABLE OF A FEW WEAK SUPERCELLS PRODUCING ISOLATED LARGE HAIL AND
SEVERE WIND GUSTS ACROSS EASTERN UTAH, THE FOUR CORNERS REGION, MUCH
OF COLORADO, AND SOUTHERN WYOMING.
..BENTLEY.. 09/10/2025
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page