MD 1849 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR SOUTHERN TO EASTERN UTAH AND WESTERN COLORADO
Mesoscale Discussion 1849 NWS Storm Prediction Center Norman OK 0102 PM CDT Fri Sep 30 2022 Areas affected...Southern to eastern Utah and western Colorado Concerning...Severe potential...Watch unlikely Valid 301802Z - 302000Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorms developing across southern and eastern Utah will gradually increase in intensity through the afternoon. These storms may produce strong to severe wind gusts, but will most likely remain too limited in coverage to require watch issuance. DISCUSSION...Convection across central/southern UT has shown signs of gradual intensification over the past 1-2 hours with deepening echo tops and a steady increase in lightning counts. This trend is likely being driven by a diurnal increase in buoyancy coupled with broad, but persistent lift ahead of an upper-level perturbation embedded within the circulation of the upper low over ID. As this perturbation continues to pivot east into UT, deep-layer shear will increase to around 30-40 knots and support storm organization. Modest low-level moisture will limit overall instability, but steep mid-level lapse rates (sampled by the 12 UTC SLC and GJT soundings) will support 500-1000 J/kg MUCAPE by mid/late afternoon. The low boundary-layer moisture content will also support steep low-level lapse rates where skies remain mostly clear. Latest RAP mesoanalysis estimates suggest 0-3 km lapse rates may already be as high as 8 C/km ahead of the deepening convection, which will support downdraft acceleration. A few instances of marginally severe hail are possible given the thermodynamic and somewhat elongated wind profiles, but strong to severe wind gusts will likely be the predominant hazard given the low-level thermodynamics. The isolated to scattered nature of the convection, coupled with the modulating effects of modest buoyancy, should limit the overall severe potential and the need for a watch this afternoon. ..Moore/Bunting.. 09/30/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GJT...SLC... LAT...LON 39121095 39771010 40030929 39950858 39600806 38760768 37700816 37430902 37181051 37141166 37111248 37851264 38331214 39121095