696  
ACUS11 KWNS 171947  
SWOMCD  
SPC MCD 171946  
IDZ000-172215-  
 
MESOSCALE DISCUSSION 2304  
NWS STORM PREDICTION CENTER NORMAN OK  
0246 PM CDT THU SEP 17 2026  
 
AREAS AFFECTED...PARTS OF SOUTHERN AND CENTRAL IDAHO  
 
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY  
 
VALID 171946Z - 172215Z  
 
PROBABILITY OF WATCH ISSUANCE...20 PERCENT  
 
SUMMARY...THE RISK OF A FEW SEVERE STORMS CAPABLE OF PRODUCING LARGE  
HAIL AND SEVERE WIND GUSTS WILL INCREASE THROUGH THE REMAINDER OF  
THE AFTERNOON. A WATCH IS NOT CURRENTLY EXPECTED, THOUGH TRENDS ARE  
BEING MONITORED.  
 
DISCUSSION...THUNDERSTORMS ARE GRADUALLY INCREASING IN COVERAGE  
ACROSS PARTS OF SOUTHERN AND CENTRAL ID. THESE STORMS ARE BEING  
AIDED BY INCREASING LARGE-SCALE FORCING FOR ASCENT PRECEDING A  
CLOSED MIDLEVEL LOW OVER NORTHERN CA AND LOCALIZED TERRAIN  
CIRCULATIONS. THESE STORMS WILL CONTINUE DEVELOPING AND SPREADING  
NORTHWARD ACROSS SOUTHERN INTO CENTRAL ID THIS AFTERNOON, GIVEN DEEP  
SOUTHERLY STEERING FLOW. THE 18Z BOI SOUNDING SAMPLED STEEP  
DEEP-LAYER LAPSE RATES AND AN ELONGATING/MOSTLY STRAIGHT HODOGRAPH  
(AROUND 30-40 KT OF CLOUD-LAYER SHEAR PER VWP AND MESOANALYSIS  
DATA). INITIALLY, CELLULAR STORMS WILL POSE A RISK OF LARGE HAIL AND  
LOCALLY SEVERE WIND GUSTS. WITH TIME, STORMS MAY ORGANIZE INTO SMALL  
CLUSTERS AND POSE AN INCREASING RISK OF SEVERE WIND GUSTS.  
 
CURRENTLY, THE RISK APPEARS TOO LOCALIZED FOR A WATCH, THOUGH  
CONVECTIVE TRENDS ARE BEING MONITORED.  
 
..WEINMAN/HART.. 09/17/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...PIH...MSO...BOI...  
 
LAT...LON 42241289 42401350 42681421 43511524 43861557 44261571  
44561562 44741525 44731470 44431345 44131257 43801213  
43221198 42691207 42271250 42241289  
 
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
 
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