Spot Forecast
Issued by NWS Salt Lake City, UT

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Spot Forecast for Granddaddy Fire...USFS
National Weather Service Salt Lake City UT
622 PM MDT Mon Sep 14 2026

Forecast is based on forecast start time of 1800 MDT on September 14.
If conditions become unrepresentative...contact the National Weather
Service.

.DISCUSSION...A stable and relatively cool airmass will remain over
the fire area through Tuesday morning, with winds diminishing and
becoming terrain-driven shortly after sunset tonight. Southwesterly
flow will overspread the area during the day Tuesday, with these
winds mixing down across exposed areas by midday. Moisture within
this flow will begin to increase during the day Tuesday, keeping
RH values elevated above 30 percent, and bringing a chance for
afternoon and evening showers and thunderstorms. Gusty outflow
winds to 40 mph and occasional lightning can be expected with any
storms which pass near the area Tuesday afternoon and evening. A
surge of moisture will arrive Tuesday night, and linger through
Wednesday, bringing several rounds of showers likely accompanied
by wetting rains. A few thunderstorms will also be mixed in with
these showers, mainly during the day Wednesday. With this increase
in moisture, excellent overnight recovery is expected Tuesday night
with RH values remaining above 60 percent Wednesday.

.TONIGHT...

Sky/weather.........Mostly clear (15-25 percent cloud cover).
CWR.................0 percent.
Chance of pcpn......0 percent.
Chance of lightning.0 percent.
Min temperature.....Around 40.
Max humidity........50-55 percent.
Wind (20 ft)........West-northwest 4-7 mph with gusts 10-14 mph
                    early, becoming down-drainage 2-5 mph after 2000.

.TUESDAY...

Sky/weather.........Mostly sunny (20-30 percent cloud cover) in
                    the morning, then partly cloudy (45-60 percent
                    cloud cover) in the afternoon. A chance of
                    showers and thunderstorms, mainly after 1200.
CWR.................10 percent.
Chance of pcpn......30 percent.
Chance of lightning.20 percent.
Max temperature.....54-58.
Min humidity........35-40 percent.
Wind (20 ft)........Terrain-driven 2-5 mph until 1100, then becoming
                    southwest 6-10 mph with gusts around 20 mph
                    during the afternoon. Gusty outflow winds to 40
                    mph near thunderstorms in the afternoon.

.TUESDAY NIGHT...

Sky/weather.........Mostly cloudy (80-90 percent cloud cover).
                    Showers with a chance of thunderstorms, mainly
                    after midnight.
CWR.................50 percent.
Chance of pcpn......80 percent.
Chance of lightning.20 percent.
Min temperature.....40-44.
Max humidity........95-99 percent.
Wind (20 ft)........South 5-9 mph. Gusty outflow winds to 30 mph
                    near thunderstorms.

.WEDNESDAY...

Sky/weather.........Mostly cloudy (75-85 percent cloud cover).
                    Occasional showers through the day. A slight
                    chance of thunderstorms, mainly in the
                    afternoon.
CWR.................60 percent.
Chance of pcpn......80 percent.
Chance of lightning.33 percent.
Max temperature.....54-58.
Min humidity........60-65 percent.
Wind (20 ft)........South 5-10 mph. Gusty outflow winds to 30 mph
                    near thunderstorms.

$$
Forecaster...Seaman
Requested by...Daniel Squires
Type of request...WILDFIRE
.TAG 2621896.0/SLC
.DELDT 09/14/26
.FormatterVersion 2.0.0
.EMAIL dsqui031@gmail.com