SPC MD 683

MD 0683 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN LOWER MICHIGAN AND NORTHWEST OHIO Mesoscale Discussion 0683 NWS Storm Prediction Center Norman OK 1229 PM CDT Sat May 09 2026 Areas affected...Eastern Lower Michigan and northwest Ohio Concerning...Severe potential...Watch unlikely Valid 091729Z - 091930Z Probability of Watch Issuance...5 percent SUMMARY...Gradual thunderstorm intensification is anticipated through mid-afternoon across far eastern Lower Michigan and northwest Ohio. Overall thunderstorm intensity and coverage should be sufficiently limited to preclude watch issuance. DISCUSSION...Latest regional radar imagery shows the early stages of convective initiation across eastern MI as a cold front begins to impinge on a plume of modest moisture (dewpoints in the low 50s). MRMS VIL data and lightning trends also show steady growth of these cells, suggesting that this is likely the onset of the severe threat that is expected to materialize through the day across the Lake Erie region as the front continues to push east. Although buoyancy will remain fairly marginal (MLCAPE values are currently estimated to be around 250 J/kg, but may increase to around 500 J/kg over the next few hours), regional VWPs are sampling strong flow aloft that is supporting 0-6 km BWD values on the order of 50 knots. Forecast soundings suggest that as convection matures it should reach sufficient depth to utilize this wind shear, leading to gradual organization and intensification. Sporadic large hail, possibly up to 1.5 inches in diameter, and damaging gusts will become increasingly possible before convection migrates over Lake Erie/portions of southern Ontario in the coming hours. The overall marginal thermodynamic environment should modulate convective intensity on the whole and support primarily a localized severe threat. ..Moore/Gleason.. 05/09/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CLE...DTX...IWX...GRR... LAT...LON 40938461 41148480 41498493 41808488 42038474 42308430 43118332 43618299 43908287 44028277 44058254 43968225 43448203 42918203 42258242 41428296 40918361 40858399 40938461 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more