877
ACUS11 KWNS 301834
SWOMCD
SPC MCD 301833
SDZ000-NDZ000-MTZ000-WYZ000-302100-
MESOSCALE DISCUSSION 2174
NWS STORM PREDICTION CENTER NORMAN OK
0133 PM CDT SUN AUG 30 2026
AREAS AFFECTED...PARTS OF EASTERN MONTANA...NORTHEASTERN
WYOMING...NORTHWESTERN SOUTH DAKOTA...WESTERN NORTH DAKOTA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 301833Z - 302100Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...STRONG TO SEVERE WIND GUSTS MAY INCREASE IN ASSOCIATION
WITH THUNDERSTORM ACTIVITY SPREADING TOWARD TOWARD THE
MONTANA/WYOMING/WESTERN DAKOTAS STATE BORDER VICINITY, WHILE
INITIALLY MORE ISOLATED STORMS WITH POTENTIAL TO PRODUCE SEVERE HAIL
BEGIN TO DEVELOP ACROSS WESTERN NORTH DAKOTA, THROUGH 2-4 PM MDT.
DISCUSSION...THUNDERSTORM DEVELOPMENT TO THE WEST/NORTHWEST OF MILES
CITY MT HAS SHOWN SOME RECENT INTENSIFICATION, WITHIN A BROADER
CLUSTER OF ONGOING CONVECTION WHICH HAS BEEN SPREADING
EAST-NORTHEAST OF THE ROCKIES. THIS APPEARS GENERALLY FOCUSED NEAR
THE LEADING EDGE OF STRONGER MID-LEVEL FORCING FOR ASCENT AND
COOLING ASSOCIATED WITH A FAIRLY SIGNIFICANT SHORT WAVE TROUGH
FORECAST TO CONTINUE PIVOTING INTO THE GREAT PLAINS THROUGH EARLY
EVENING. LATEST RAPID REFRESH OUTPUT, AMONG OTHER GUIDANCE,
INDICATES THAT THIS WILL BE ACCOMPANIED BY STRENGTHENING OF WESTERLY
WINDS (AT LEAST ON THE ORDER OF 30-50+ KT IN THE 850-500 MB LAYER)
IN A BELT ACROSS EASTERN MONTANA INTO THE WESTERN DAKOTAS, PERHAPS
AIDED BY THE DOWNWARD MOMENTUM TRANSPORT WITHIN THE CONVECTION.
THIS IS BEING PRECEDED BY A BOUNDARY-LAYER UNDERGOING MODEST WARMING
AND MIXING, BUT, AT THE SAME TIME, WEAK COLD ADVECTION, ACROSS
EASTERN MONTANA, AND GRADUALLY NORTHEASTERN WYOMING, TOWARD SURFACE
TROUGHING NEAR THE DAKOTAS/MONTANA STATE BORDER VICINITY. SO, THE
DEGREE OF DESTABILIZATION WITHIN THE LOW-LEVEL EASTERLY UPDRAFT
INFLOW SUPPORTING ACTIVITY MAY NOT IMPROVE MUCH IN THE NEAR TERM.
EVEN SO, BASED ON CONVECTION-ALLOWING MODEL OUTPUT, CONTINUING
DOWNWARD MOMENTUM TRANSFER WITHIN A WARMER AND MORE DEEPLY MIXED
BOUNDARY-LAYER MAY EVENTUALLY BE ACCOMPANIED BY INCREASING STRONG TO
SEVERE WIND GUSTS REACHING THE SURFACE, PARTICULARLY ACROSS PARTS OF
SOUTHEASTERN MONTANA AND ADJACENT NORTHEASTERN WYOMING THROUGH
20-22Z.
AT THE SAME TIME, FORCING FOR ASCENT MAY BEGIN TO OVERCOME LINGERING
INHIBITION WITHIN THE MORE MOIST BOUNDARY-LAYER TO THE EAST OF THE
SURFACE TROUGH AXIS, ACROSS WESTERN NORTH DAKOTA, WHERE MIXED-LAYER
CAPE MAY CONTINUE TO INCREASE UP TO AROUND 2000 J/KG, IN THE
PRESENCE OF STRENGTHENING DEEP-LAYER SHEAR. THIS MAY SUPPORT, AT
LEAST INITIALLY, MORE DISCRETE THUNDERSTORM DEVELOPMENT, INCLUDING A
COUPLE OF EVOLVING SUPERCELLS.
..KERR/MOSIER.. 08/30/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ABR...BIS...UNR...BYZ...GGW...
LAT...LON 49070279 48340163 45920168 45020299 44600475 45220644
46480581 47470527 48190543 48910447 49070279
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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