025
ACUS11 KWNS 021749
SWOMCD
SPC MCD 021749
MTZ000-022015-
MESOSCALE DISCUSSION 2200
NWS STORM PREDICTION CENTER NORMAN OK
1249 PM CDT WED SEP 02 2026
AREAS AFFECTED...WESTERN MONTANA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 021749Z - 022015Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...THE POTENTIAL FOR SEVERE WIND GUSTS SHOULD INCREASE
STEADILY THROUGH LATE AFTERNOON ACROSS WESTERN AND NORTHERN MONTANA.
WATCH ISSUANCE IS EXPECTED BY 20-21 UTC AS THUNDERSTORMS BEGIN TO
INTENSIFY.
DISCUSSION...LATEST GOES IMAGERY DEPICTS A PRONOUNCED VORTICITY
MAXIMUM TRAVERSING CENTRAL ID AND APPROACHING WESTERN MT. AHEAD OF
THIS FEATURE, WEAK CONVECTION HAS BEEN PERCOLATING WITHIN A BROAD
SWATH OF MORE STRATIFORM PRECIPITATION. ALTHOUGH CONVECTIVE
INTENSITY HAS BEEN MODEST SO FAR, STEADY INTENSIFICATION APPEARS
PROBABLE THROUGH THE AFTERNOON HOURS AS LOW-LEVEL DESTABILIZATION
OCCURS AHEAD OF THE WAVE. BASED ON A CONSENSUS OF RECENT GUIDANCE,
ANY LINGERING INHIBITION DOWNSTREAM SHOULD BE LARGELY REMOVED AS
TEMPERATURES WARM INTO THE MID/UPPER 80S, WHICH WILL SUPPORT NOT
ONLY STEEP LOW-LEVEL LAPSE RATES, BUT ALSO MLCAPE VALUES ON THE
ORDER OF 250-500 J/KG. IN GENERAL, BUOYANCY MAGNITUDES ARE EXPECTED
TO REMAIN FAIRLY MODEST, AND EFFECTIVE SHEAR THROUGH THE
CAPE-BEARING LAYER IS ONLY FORECAST TO REACH INTO THE 25-30 KNOT
RANGE. THIS COMBINATION MAY SUPPORT A FEW ORGANIZED STORMS CAPABLE
OF PRODUCING MARGINALLY SEVERE HAIL THROUGH LATE AFTERNOON, THOUGH
SEVERE WIND SHOULD BE THE PREDOMINANT CONVECTIVE HAZARD.
THE PRIMARY DRIVER OF THE SEVERE WIND POTENTIAL WILL MORE LIKELY BE
THE STRONG DOWNSLOPE FLOW OFF THE TERRAIN OF THE NORTHERN ROCKIES AS
THE MID-LEVEL WAVE (AND AN ATTENDANT JET) OVERSPREAD WESTERN MT
THROUGH THE AFTERNOON. EVIDENCE OF THIS IS ALREADY NOTED VIA 30-35
MPH GUSTS ACROSS SOUTH-CENTRAL MT AWAY FROM ONGOING PRECIPITATION.
AS CONVECTION GRADUALLY INTENSIFIES THROUGH THE AFTERNOON AND
LOW-LEVEL LAPSE RATES STEEPEN, CONVECTIVE AUGMENTATION TO THE
BACKGROUND GRADIENT WIND FIELD WILL LIKELY RESULT IN SWATHS OF 60-80
MPH WINDS, EVEN WITH OTHERWISE ANEMIC CONVECTION WITH POOR RADAR
PRESENTATION.
CONFIDENCE IN THE SEVERE WIND THREAT IS GREATEST ACROSS PORTIONS OF
NORTH-CENTRAL MT WHERE A COMBINATION OF MOSTLY CLEAR SKIES SHOULD
MAXIMIZE DIURNAL HEATING, AND THE PASSAGE OF THE MID-LEVEL JET AXIS
WILL MAXIMIZE DOWNWARD MOMENTUM TRANSFER WITHIN CONVECTIVE CELLS.
LATEST TIME-LAGGED CAM GUIDANCE HAS CONSISTENTLY SHOWN THE STRONGEST
SIGNAL ACROSS THIS CORRIDOR DURING THE 22-01 UTC PERIOD, THOUGH
STRONG/SEVERE GUSTS MAY BEGIN EARLIER WITHIN THE HIGHER TERRAIN OF
WEST/SOUTHWEST MT. REGARDLESS, CONVECTIVE TRENDS ARE BEING MONITORED
AND WATCH ISSUANCE IS LIKELY AS DOWNSTREAM DESTABILIZATION CONTINUES
AND ONGOING CONVECTION BEGINS TO INTENSIFY.
..MOORE/GLEASON.. 09/02/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...TFX...MSO...
LAT...LON 45571239 45561291 45741337 46141382 46861430 47851464
48591489 49031454 49030971 48910922 48500887 47950907
47320952 46241087 45941133 45711180 45571239
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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