Mesoscale Discussion 0878
NWS Storm Prediction Center Norman OK
0350 PM CDT Wed May 27 2026
Areas affected...portions of the Pacific Northwest and northern
Great Basin
Concerning...Severe potential...Watch unlikely
Valid 272050Z - 272215Z
Probability of Watch Issuance...5 percent
SUMMARY...Scattered storms on the northern periphery of a deep upper
low may pose a risk for severe wind gusts or hail.
DISCUSSION...As of 2045 UTC, regional radar imagery showed scattered
thunderstorms intensifying over portions of northern NV, eastern OR
and southwestern ID. Aided by ascent from an embedded shortwave
trough on the northern periphery of a deep upper low over the West
Coast, additional storm development/intensification is likely this
afternoon and evening. Filtered diurnal heating, relatively moist
surface conditions for May (dewpoints near 50 F) and cold
temperatures aloft are helping to support moderate destabilization
with 500-1000 J/kg of MLCAPE present. An increase in lightning and
cooling cloud tops over the last few hours suggests convection is
maturing, with several stronger updrafts noted.
50+ kt of east/southeasterly flow aloft is evident on area VADs and
RAP soundings. Veering wind profiles with northwesterly storm
motions will be sufficient for occasional storm organization into
multi cell clusters or occasional supercells. The steep low and
mid-level lapse rates will support a risk for severe/damaging gusts
given the potential for strong downdrafts. However, some hail is
also possible, especially with any rotating storms.
The primary limiting factor remains the more limited instability.
Cloud cover has lingered farther west, curtailing diurnal
destabilization. While cold mid-level temperatures will allow for
some destabilization beneath the northern parts of the upper low,
persistent storm organization may be confined to areas of better
buoyancy. Thus, some severe wind and hail risk is evident over parts
of northern NV, southeast OR, and southwestern ID through this
evening. However, confidence in a widespread sustained severe risk
is low and a WW is unlikely.
..Lyons/Gleason.. 05/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PIH...MSO...BOI...LKN...OTX...PDT...REV...MFR...
STO...PQR...
LAT...LON 42892292 44412143 45481898 46131677 45731516 44211413
42801567 41421903 41122099 41242183 41392231 42892292
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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