404
ACUS11 KWNS 271843
SWOMCD
SPC MCD 271843
NEZ000-SDZ000-272045-
MESOSCALE DISCUSSION 2149
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CDT THU AUG 27 2026
AREAS AFFECTED...PORTIONS OF THE BLACK HILLS INTO NORTHWESTERN AND
WEST-CENTRAL NEBRASKA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 271843Z - 272045Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...THUNDERSTORMS FORMING ON THE BLACK HILLS WILL EVOLVE
SOUTHEASTWARD THROUGH THE EVENING, BRINGING A RISK FOR LARGE TO VERY
LARGE HAIL AND SEVERE WIND GUSTS.
DISCUSSION...LATEST SURFACE ANALYSIS DEPICTS A CORRIDOR OF LOW-60S F
DEWPOINTS ACROSS NORTHWESTERN NEBRASKA AND SOUTHWESTERN SOUTH DAKOTA
THAT HAVE BEEN MAINTAINED BY MOIST SOUTHERLY/SOUTHEASTERLY LOW-LEVEL
FLOW. COMBINED WITH STRONG DIURNAL HEATING AND WEAK ASCENT
ASSOCIATED WITH A SUBTLE MID-LEVEL WAVE PROGRESSING SOUTHEASTWARD
OUT OF EASTERN MONTANA, CONVECTIVE INITIATION IS LIKELY ACROSS THE
BLACK HILLS WITHIN THE NEXT 1-2 HOURS. SUPERCELLS WILL BE THE
INITIAL STORM MODE OWING TO STRONG NORTHWESTERLY FLOW ALOFT AND
40-45 KTS OF EFFECTIVE SHEAR. WHILE SOME UNCERTAINTY REMAINS
REGARDING CONVECTIVE EVOLUTION (PARTICULARLY SUPERCELL LONGEVITY AND
THE POTENTIAL FOR EVENTUAL UPSCALE GROWTH), VERY STEEP MID-LEVEL
LAPSE RATES AND ELONGATED HODOGRAPHS SAMPLED BY THE 18Z UNR OBSERVED
SOUNDING WILL SUPPORT A RISK FOR LARGE TO VERY LARGE HAIL (UP TO
2-3+ INCHES IN DIAMETER) WITH ANY SUSTAINED SUPERCELLS. SEVERE TO
PERHAPS SIGNIFICANT SEVERE WIND GUSTS OF 65-75 MPH MAY ALSO OCCUR
WITH THESE SUPERCELLS, WITH A GREATER THREAT FOR SEVERE GUSTS LIKELY
TO ACCOMPANY ANY CONVECTIVE CLUSTER THAT EVENTUALLY EVOLVES AS THIS
ACTIVITY PROGRESSES SOUTHEASTWARD. REGARDLESS OF THE EXACT STORM
MODE EVOLUTION, A SEVERE THUNDERSTORM WATCH WILL LIKELY BE NEEDED
ONCE CONVECTIVE DEVELOPMENT CURRENTLY NOTED OVER THE BLACK HILLS
MATURES.
..CHALMERS/MOSIER.. 08/27/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...LBF...UNR...CYS...
LAT...LON 44280348 43540157 43030059 42710030 42330028 41850058
41500113 41320192 41520251 42000294 43020345 44050394
44310382 44280348
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page