FNUS75 KSLC 220450
FWSSLC

Spot Forecast for Harley...Northern Utah IFC
National Weather Service Salt Lake City UT
1050 PM MDT Fri Aug 21 2026

Forecast is based on forecast start time of 2300 MDT on August 21. 
If conditions become unrepresentative...contact the National Weather
Service.

...HEAT ADVISORY IN EFFECT UNTIL 7 AM MDT SATURDAY...

.DISCUSSION...For the next few hours: showers and thunderstorms
over the Utah Valley as of this writing will continue northward,
most likely reaching the fire in 2 to 3 hours. These showers will
be relatively weak, but will bring a 30-40 percent chance of gusty
and erratic winds over the fire and a 10 percent chance of
lightning. Showers will diminish as sunrise approaches. 

For tomorrow and beyond, monsoon moisture will remain in place
Saturday, bringing the development of showers and thunderstorms in
the afternoon, primarily focused over the higher terrain. However,
there will be a 20 percent chance during the day that a storm will
impact the fire. During the evening and into the early part of the
overnight hours, a weak cold front will move into northwest Utah
as it weakens. This will bring a chance (30-40 percent) of showers
that could bring some erratic winds gusts. The airmass over the
area will dry somewhat Sunday into Monday, but at least some
potential for showers and thunderstorms will exist each day. 

.REST OF TONIGHT...

Sky/weather.........Mostly cloudy (80-90 percent cloud cover). 
CWR.................15 percent. 
Chance of pcpn......40 percent. 
Chance of lightning.10 percent. 
Min temperature.....68-72. 
Max humidity........60-62 percent. 
Wind (20 ft)........Downslope/downvalley winds 3-7 mph. Gusty and 
                    erratic winds expected near thunderstorms overnight. 
Mixing height.......500 ft AGL. 
Transport winds.....South winds 8-12 mph. 

.SATURDAY...

Sky/weather.........Partly cloudy (40-50 percent cloud cover). 
CWR.................5 percent. 
Chance of pcpn......20 percent. 
Chance of lightning.5 percent. 
Max temperature.....92-96. 
Min humidity........24-28 percent. 
Wind (20 ft)........Upslope/upvalley winds 3-7 mph becoming south
                    8-12 mph in the afternoon.
Mixing height.......10100 ft AGL (60-70th Percentile). 
Transport winds.....Southwest winds 10-15 mph. Gusty and erratic
                    winds expected near thunderstorms in the 
                    afternoon.  

.SATURDAY NIGHT...

Sky/weather.........Partly cloudy (45-55 percent cloud cover). 
                    Slight chance of showers and thunderstorms 
                    overnight. 
CWR.................10 percent. 
Chance of pcpn......30 percent. 
Chance of lightning.15 percent. 
Min temperature.....66-70. 
Max humidity........62-66 percent. 
Wind (20 ft)........Southwest winds 5-10 mph becoming 
                    downslope/downvalley 3-7 mph overnight. Gusty 
                    and erratic winds expected near thunderstorms 
                    overnight. 
Mixing height.......500 ft AGL. 
Transport winds.....Southwest winds 8-12 mph.

.SUNDAY...

Sky/weather.........Mostly sunny (10-20 percent cloud cover). 
CWR.................5 percent. 
Chance of pcpn......20 percent. 
Chance of lightning.10 percent. 
Max temperature.....92-96. 
Min humidity........24-28 percent. 
Wind (20 ft)........Upslope/upvalley winds 3-7 mph becoming south
                    8-12 mph in the afternoon. Gusty and erratic
                    winds expected near thunderstorms in the
                    afternoon.
Mixing height.......700 ft AGL increasing to 11600 ft AGL in the 
                    afternoon (70-80th Percentile). 
Transport winds.....Southwest winds 8-12 mph. 

$$
Forecaster...Traphagan
Requested by...Northern Utah IFC
Type of request...WILDFIRE
.TAG 2620227.0/SLC
.DELDT 08/21/26
.FormatterVersion 2.0.0
.EMAIL trhobbs@utah.gov,utnuc@firenet.gov