676
FNUS76 KMTR 130339
FWSMTR

Spot Forecast for Altamont incident...Alameda County Fire
National Weather Service San Francisco CA
839 PM PDT Sat Sep 12 2026

Forecast is based on forecast start time of 2100 PDT on September 12.
If conditions become unrepresentative, contact the National Weather
Service.

.DISCUSSION...Strong southwest to west winds will prevail over the
next couple of days with gusts to around 35 to 40 miles per hour
persisting into Sunday. Local terrain near the incident site may
impact wind directions around the incident. Conditions remain
clear through Monday night with poor daytime humidity retention.
While marine layer clouds may return to the region Tuesday
morning, the exact impacts to the incident site will depend on the
thickness of the marine layer. If the marine layer clouds lie
below the incident site overnight, nocturnal drying events are
possible.

.REST OF TONIGHT...

Sky/weather.........Clear.
Min temperature.....55-60.
Max humidity........85-95 percent.
Wind (20 ft)........Windy. Southwest winds 28 to 32 mph with gusts
                    to around 40 mph.
CWR.................0 percent.
Chance of thunder...0 percent.
Mixing height.......400 ft AGL.
Transport winds.....Southwest around 29 mph.
Marine layer........None.

.SUNDAY...

Sky/weather.........Sunny.
Max temperature.....75-82.
Min humidity........29-33 percent.
Wind (20 ft)........Windy. Southwest winds 21 to 30 mph with gusts
                    to around 35 mph in the morning, becoming west
                    14 to 18 mph with gusts to around 24 mph
                    in the afternoon.
CWR.................0 percent.
Chance of thunder...0 percent.
Mixing height.......4400 ft AGL.
Transport winds.....West around 18 mph.
Marine layer........None.

.SUNDAY NIGHT...

Sky/weather.........Mostly clear.
Min temperature.....52-58.
Max humidity........80-90 percent.
Wind (20 ft)........Southwest winds 18 to 22 mph with gusts to
                    around 25 mph.
CWR.................0 percent.
Chance of thunder...0 percent.
Mixing height.......400 ft AGL.
Transport winds.....West around 17 mph.
Marine layer........None.

.MONDAY...

Sky/weather.........Sunny.
Max temperature.....80-85.
Min humidity........21-25 percent.
Wind (20 ft)........West winds 14 to 20 mph with gusts to around 25
                    mph.
CWR.................0 percent.
Chance of thunder...0 percent.
Mixing height.......4700 ft AGL.
Transport winds.....Northwest around 15 mph.
Marine layer........None.

$$
Forecaster...D_HOANG
Requested by...Brian Diregolo
Type of request...WILDFIRE
.TAG 2621755.0/MTR
.DELDT 09/12/26
.FormatterVersion 2.0.0
.EMAIL brian.diregolo@alamedacountyfire.gov