290  
ACUS11 KWNS 182152  
SWOMCD  
SPC MCD 182152  
MIZ000-WIZ000-182345-  
 
MESOSCALE DISCUSSION 2028  
NWS STORM PREDICTION CENTER NORMAN OK  
0452 PM CDT TUE AUG 18 2026  
 
AREAS AFFECTED...NORTHERN LOWER MICHIGAN PENINSULA  
 
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE  
 
VALID 182152Z - 182345Z  
 
PROBABILITY OF WATCH ISSUANCE...40 PERCENT  
 
SUMMARY...LARGE HAIL AND DAMAGING WIND WILL BE POSSIBLE WITH  
ISOLATED SUPERCELLS THIS EVENING.  
 
DISCUSSION...THUNDERSTORM ACTIVITY IS SHIFTING EASTWARD ACROSS LAKE  
MICHIGAN THIS EVENING. DOWNSTREAM, THE AIR MASS IS ONLY MARGINALLY  
UNSTABLE, WITH MLCAPE AROUND 250-500 J/KG. DEEP LAYER FLOW IS  
SEASONABLY STRONG, WITH DEEP LAYER SHEAR 35-45 KTS ACROSS THE  
NORTHERN LOWER MICHIGAN PENINSULA. RAOB PROFILES FROM APX (GAYLORD,  
MI) SHOWS A LONG STRAIGHT HODOGRAPH, WHICH WOULD BE SUPPORTIVE OF  
SPLITTING SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WIND.  
DAMAGING WIND POTENTIAL MAY BE FURTHER SUPPORTED BY STEEP LOW LEVEL  
LAPSE RATES (AROUND 8 C/KM). THERE REMAINS SOME UNCERTAINTY WITH HOW  
LONG SUPERCELLS WILL BE SUSTAINED, GIVEN THE ONLY MARGINALLY  
FAVORABLE THERMODYNAMICS. THIS AREA WILL BE MONITORED FOR WATCH  
POTENTIAL.  
 
..THORNTON/GLEASON.. 08/18/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...DTX...APX...GRR...MQT...GRB...MKX...  
 
LAT...LON 44878784 45708653 46048525 46048401 45588292 45038228  
44148251 43428347 43398547 43448661 43768773 44278801  
44878784  
 
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab SPC Page
Main Text Page