882  
FNUS75 KSLC 210035  
FWSSLC  
 
SPOT FORECAST FOR SUBWAY SAR...ZION NATIONAL PARK  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
635 PM MDT THU AUG 20 2026  
 
FORECAST IS BASED ON FORECAST START TIME OF 1900 MDT ON AUGUST 20.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION  
ONGOING SHOWERS AND THUNDERSTORMS OVER THE HIGHER  
TERRAIN OF SOUTHERN UTAH ARE MOVING LITTLE OR SLOWLY TO THE EAST  
EARLY THIS EVENING. THE CHANCE OF ADDITIONAL DEVELOPMENT THROUGH  
THE EVENING THAT WOULD IMPACT THE PARK IS VERY LOW (10 PERCENT OR  
LESS), WITH THE CHANCE DECREASING MID TO LATE EVENING. SOME  
GUIDANCE IS INDICATING SOME ADDITIONAL DEVELOPMENT OF SHOWERS  
DURING THE OVERNIGHT HOURS, IN THE MIDNIGHT TO 5AM TIME RANGE,  
WITH THE PASSAGE OF A WEAK SHORTWAVE AND WOULD GIVE THESE A 20  
PERCENT CHANCE OF DIRECTLY IMPACTING THE PARK. IF STORMS DO  
DEVELOP OVERNIGHT, THEY WOULD MOST LIKELY BE QUITE A BIT WEAKER  
THAN THE CURRENT DAYTIME CONVECTION. SHOULD OPERATIONS CONTINUE  
INTO TOMORROW, MONSOON MOISTURE WILL BE INCREASING FROM THE SOUTH  
DURING THE DAY, SO COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS  
WOULD BE MORE WIDESPREAD THAN TODAY.  
   
REST OF TONIGHT  
 
SKY/WEATHER.........PARTLY CLOUDY (35-45 PERCENT CLOUD COVER). A  
SLIGHT CHANCE OF SHOWERS OVERNIGHT.  
CHANCE OF PCPN......20 PERCENT.  
CHANCE OF LIGHTNING.5 PERCENT.  
MIN TEMPERATURE.....60-64.  
MAX HUMIDITY........58-62 PERCENT.  
SURFACE WINDS (MPH).SOUTHWEST WINDS 5-10 MPH BECOMING  
UPSLOPE/UPVALLEY 3-7 MPH LATE EVENING AND  
OVERNIGHT.  
 
 
FORECASTER...TRAPHAGAN  
REQUESTED BY...RICHARD DEINES  
TYPE OF REQUEST...SAR  
.TAG 2620135.0/SLC  
.DELDT 08/20/26  
.FORMATTERVERSION 2.0.0  
.EMAIL ZION_DISPATCH@NPS.GOV  
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