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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PST Sat Feb 7 2026

...FRONTAL SYSTEM TO SPREAD ATMOSPHERIC RIVER CONDITIONS ACROSS THE 
NORTH BEGINNING TODAY, WEAKENING BEFORE GETTING TO THE I80 
CORRIDOR...
...ANOTHER WEAK SYSTEM TO MOVE ONSHORE TUESDAY AND SPREAD WEAK 
PRECIPITATION ACROSS MUCH OF THE FORECAST AREA...

.METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)...

The East Pacific ridge that has been keeping the forecast area 
relatively dry for an extended period has begun to flatten out and 
positively tilt towards the northeast allowing for an oceanic 
disturbance to start making it's way towards the northern portions 
of California and the southern Cascades. Atmospheric river 
conditions will begin moving over the Smith Basin later today and 
begin spreading southward into tomorrow. The strongest onshore 
moisture transport (IVT >500 units) will be confined to Del Norte 
and northern Humboldt counties, though weak AR conditions may make 
it as far south as the I-80 corridor before dissipating. This will 
keep most of the precipitation over the next 48-hours north of the 
Bay Area and the Tahoe Basin. The heaviest accumulations are 
currently targeting the Smith basin where onshore flow will be 
strongest with >2 inches. Lighter acumulations are forecast for 
areas further south and east. 

Things become much more uncertain early next week as most guidance 
agrees that another weak system will move onshore over central 
California but diverge on exact timing and precipitation amounts and 
location. The current forecast focuses most of the heaviest 
precipitation accumulations over the Sierra with lighter 
accumulations across much of California and into Nevada. Expect 
updates to the QPF as guidance begins to come into focus for Tuesday 
into Thursday morning. 

Freezing levels across the north will start the period above 8k feet 
before dropping to below 6k feet with the frontal passage and 
digging system. Levels across the Sierra could lower to ~5k feet 
through mid-week as the weaker system moves onshore.

Please Note: This product may NOT be routinely updated.
Please refer to the following product issued by the CNRFC
www.cnrfc.noaa.gov/Daily-Briefing for a graphical summary of weather 
and hydrologic conditions.