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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PST Mon Feb 9 2026

...RELATIVELY DRY CONDITIONS THROUGHOUT TODAY BEFORE A DEVELOPING 
LOW TRACKS OVER NORTHERN CALIFORNIA COAST TOMORROW MORNING...
...TROUGHING LOOKS TO KEEP CONDITIONS ACTIVE WITH ADDITIONAL 
ACTIVITY OVER THE WEEKEND...

.SHORT TERM METEOROLOGICAL CONDITIONS (MON AM - THU AM)...

Precipitation associated with a frontal system has mostly moved out 
of the forecast area with only light showers remaining over 
northeastern Nevada and and the Owens Valley. Conditions will remain 
mostly dry for the rest of today before a low pressure develops off 
the central California coast early Tuesday and begin moving onshore 
around 18Z tomorrow. This low will cutoff from the upper level flow 
over the coast of California and result in a relatively slow moving 
surface low that pinwheels off the CA coast. This pinwheel effect 
will introduce larger uncertainty as the exact location and track of 
developing showers is in question. As the low slowly tracks 
northward, the cold front and moisture plume with onshore IVT around 
500 units will pivot around Point Conception and bring southerly 
upslope moisture flux to the Transverse Range in southern 
California. 

The heaviest precipitation accumulations during the next three days 
will likely target where the low tracks across northern CA and where 
the onshore moisture flux is strongest across the Big Sur and 
southern California Coasts. Current forecasts have 1.25 to 2.75 
inches over the North Bay Mountains and northern Sierra (Feather 
Basin). Further South, the Big Sur Coast is forecast to receive 3+ 
inches while the higher Elevations of the Transverse Range could see 
1.25 to 2.15 inches. 

Freezing levels over the Northern Sierra will start the period ~7k 
feet before lowering under the approaching low to ~5k feet. Across 
the SoCal mountains, levels will start the period above 11k feet 
and lower to ~8k feet by Thursday. 

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.

.LONG TERM METEOROLOGICAL CONDITIONS (THU AM - SUN AM)...

Troughing overhead early Thursday will result in some scattered 
showers over parts of central CA, the Sierra, and NV. NOt expecting 
more than 0.10" at this time. The system will shift to the south the 
rest of the day with the core of the trough offshore of Baja by the 
evening and moving inland overnight through Friday afternoon. As the 
trough exits, a brief ridge will move into nrn CA/NV bringing dry 
conditions for Friday. Another trough will drop in from the 
northwest on Saturday resulting in more widespread precip for nrn 
and central CA. There are some timing differences between the 
models. The GFS shows the arrival of precip along the north coast 
Friday evening while the ECMWF holds off until Saturday morning. 
ECMWF AI ensemble members have arrival times anywhere in that range 
making for some uncertainty. The 24 hr QPF spread at Blue Canyon is 
anywhere from 0 to about 2" between the ECMWF and the GEFS. Expect 
lowering freezing levels throughout the weekend from 8-11 kft to 
maybe 4-7 kft, though again uncertainty on the timing.

Majority of the precip in the extended is expected on Saturday with 
that larger trough. QPF on Friday about 0.10-0.25" over the Smith 
Basin and a few hundredths to 0.10" along the rest of the north 
coast. For Saturday, 0.50-1.25" northern/central Sierra/north coast, 
0.50-1" Shasta, 0.10-0.50" Bay Area/central coast, and generally 
0.10-0.75" for the rest of nrn/cntrl CA.


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.