Mesoscale Discussion 1877
Issued: · Valid: –
Summary
Severe thunderstorms capable of producing damaging winds may develop across portions of southern Wisconsin and northern Illinois during the late morning and early afternoon.
Product Text
000 ACUS11 KWNS 091421 SWOMCD SPC MCD 091420 WIZ000-ILZ000-091545- Mesoscale Discussion 1877 NWS Storm Prediction Center Norman OK 0920 AM CDT Sun Aug 09 2026 Areas affected...Portions of southern Wisconsin into far northern Illinois Concerning...Severe potential...Watch possible Valid 091420Z - 091545Z Probability of Watch Issuance...40 percent SUMMARY...An organized bowing structure, likely elevated at present time, could become near surface based as it moves into southeastern Wisconsin and adjacent northern Illinois. Wind damage would be the main threat. A watch is possible should observational trends warrant. DISCUSSION...A small bowing cluster has been moving southeastward this morning. This activity has remained elevated thus far, but the airmass ahead of it is slowly destabilizing. Dewpoints in northern Illinois/southern Wisconsin have increased over the past couple of hours. The main limiter in terms of destabilization has been the cloud cover/smoke that has reduced insolation. Based on forecast soundings, if temperatures can reach the mid 70s F the storms will be at least near surface based. Given the current organization of ongoing convection, there may be an increase in damaging wind potential over the next couple of hours. The need for a watch is uncertain and will depend on observation trends. ..Wendt/Hart.. 08/09/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...ARX... LAT...LON 42338865 42578899 43008959 43609043 43968955 43808901 43158779 42748767 42538767 42418772 42278830 42338865 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN