Mesoscale Discussion 0886 NWS Storm Prediction Center Norman OK 0710 PM CDT Thu May 28 2026 Areas affected...central and eastern Oregon into southwest Idaho Concerning...Severe Thunderstorm Watch 248... Valid 290010Z - 290215Z The severe weather threat for Severe Thunderstorm Watch 248 continues. SUMMARY...Through 02 UTC, the greatest threat for severe wind gusts up to 60 to 70 mph and large hail up to golf-ball size will exist from central into northeast Oregon. More isolated severe weather remains possible elsewhere in the watch area. DISCUSSION...As of 00 UTC, mosaic radar data showed a broken band of severe storms, including supercell and bowing structures, across portions of Deschutes, Crook, Wheeler, and Grant Counties in central OR, moving west or northwest at 40-45 mph. The downstream environment east of the Cascades remains moderately unstable with steep lapse rates and boundary-layer dewpoints in the 50s supporting MLCAPE of 1000-1500 J/kg. And given the presence of modestly strong deep-layer shear, the setup should sustain the ongoing storms, with an attendant threat for damaging wind gusts up to 60-70 mph and hail up to golf-ball size. Farther to the northeast, scattered thunderstorms are ongoing in the vicinity of the Blue Mountains south of Pendleton, amidst a slightly more unstable environment. Numerous splitting supercells have been observed over the past couple of hours, and that trend may continue before storms congeal into clusters. Large hail up to golf-ball size will be the predominant hazard initially, with a transition to more of a damaging wind threat should storm grow into a complex with an organized cold pool. The severe-weather threat is a little more uncertain across south-central into southeast OR into far southwest ID, where instability has diminished. ..Mead.. 05/29/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MSO...BOI...OTX...PDT...MFR...PQR... LAT...LON 42782129 43592136 43622197 45712169 45692027 46011847 46021692 45581657 45311661 45071617 43451611 43011595 42691492 42001499 41992100 42782129 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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