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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
130 PM 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)...

The afternoon forecast saw some changes with regards to the cutoff 
low that is forecast to track northward along the central/northern 
coast beginning Tuesday. A shift in a majority of the guidance to a 
more southern track resulted in decreases across northern California 
of ~.3 inches, bringing 3-day accumulations across the North Coast, 
Shasta Drainage, and northern Sierra to 1-2 inches. This more 
southern track of the low also produces increases in QPF across the 
Santa Cruz mountains and southern Sierra with minor decreases along 
the Transverse range where southerly onshore moisture flux will be 
strongest. 3-day totals around the Big Sur coast, southern Sierra, 
and Transverse range from 1 to 3.75 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. 

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

Forecast overall remains on track with little changes in the 
official QPF since this morning. Troughing overhead Thursday is 
expected to generate some showers across central CA, the Sierra, and 
NV. Still not anticipating more than 0.10" for most areas, maybe a 
little higher over some of the NV mountains. The trough will move 
south the rest of the day then head eastward through Baja into 
Friday. Ridging will briefly build in over nrn CA/NV behind the 
exiting trough leaving dry conditions to end the work week. The next 
real chance of precip is expected over the weekend. There is still 
uncertainty with the timing. Both det models have slowed down the 
arrival of precip compared to earlier runs. The GFS now shows 
showers arriving with the trough to the north coast early Saturday 
while the ECMWF delays until overnight. Only about 20% of the 
overall CMC/GEFS/ECMWF ensemble members are showing this later 
timing while the rest have various Saturday arrivals. The other 
point of disagreement is on the amounts as spreads remain on the 
order of 2" or so.

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 and into Shasta. For Saturday, 0.50-1.50" north coast, 0.50-1" 
Shasta/nrn/cntrl Sierra, 0.10-0.50" Bay Area/central coast, and 
generally 0.10-0.75" for the rest of nrn/cntrl CA. This will be a 
colder system with lowering freezing levels, uncertainty due to the 
timing differences between the models.