Severe Storm Outlook Narrative (AC)
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Issued by NWS
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122 ACUS11 KWNS 172001 SWOMCD SPC MCD 172000 WIZ000-172200- Mesoscale Discussion 1304 NWS Storm Prediction Center Norman OK 0300 PM CDT Mon Jun 17 2024 Areas affected...Southern/Eastern WI Concerning...Severe potential...Watch possible Valid 172000Z - 172200Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms capable of isolated hail and/or damaging gusts are possible across southern WI this afternoon and evening. Trends will be monitored for possible watch issuance. DISCUSSION...Temperatures have warmed in the upper 80s/low 90s across southern WI/eastern WI, amid dewpoints in the upper 60s/low 70s. These very warm and moist surface conditions are helping support strong buoyancy, despite relatively poor lapse rates across the region. Recent mesoanalysis estimates MLCAPE is around 2000 to 2500 J/kg, with little to no convective inhibition. Low-level convergence along and ahead of a stationary boundary extending from OCQ (about 30 miles north-northeast of GRB) southwestward through LNR in far southwest WI is contributing to convective initiation within this unstable airmass. Vertical shear is modest across the region, with effective bulk shear less than 20 kt. This lack of stronger shear is expected to promote a predominantly multicellular mode, but a few updrafts could still become strong enough to produce severe hail and/or a strong, water-loaded downburst. Overall coverage of severe is currently expected to remain isolated, limiting the need for a watch, but convective trends will be monitored closely. ..Mosier/Gleason.. 06/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...MKX...ARX... LAT...LON 42619033 42979067 43759005 44508922 45008830 44688754 44238745 43648768 42908779 42608825 42548939 42619033