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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PDT Fri Apr 10 2026

...COOLER AND UNSETTLED WEATHER THROUGH THE WEEKEND...

.METEOROLOGICAL CONDITIONS (SHORT TERM: FRI AM - MON AM)...

Moderate to heavy showers/thunderstorms continue to spread across 
northern California as an upper level cutoff sits just off the 
NorCal coast. Shower and thunderstorm activity if forecast to 
continua throughout the day today as the upper low opens and tracks 
inland. The heaviest precipitation over the previous 2 hours has 
been focused over the North Bay (lower Russian Basin) where a line 
of heavy showers has been training. Numerous gauges around Santa 
Rose have observed >0.5 inches. Additional thunderstorms have 
initiated and are tracking northward along the Sierra around and 
just south of the I-80 corridor. QPF through the rest of today will 
focus over NorCal with the heaviest amounts targeting the Coast, 
Shasta Drainage, and the north/central Sierra with amounts over 1 
inch. Amounts are likely to be locally higher where thunderstorms 
initiate and track. 

As the current low opens and tracks inland, another stronger upper 
low, currently located in the Gulf will swing in behind it and 
continue to wet pattern into the weekend. This low will take a 
similar track but become semi-stationary on Sunday before opening 
and exiting the region. Given the stronger magnitude of the low and 
relatively slow pace, 48-hour precipitation accumulations are likely 
to be higher across northern CA, exceeding 3 inches in the Sierra 
and 2 inches in the Shasta drainage, Russian Basin, and Big Sur 
Coast. Pockets of CVA are likely to extend into southern California 
on Sunday, producing 1+ inches across some of the higher elevations 
of the Transverse. The convective nature of this storm will also 
lead to locally heavier accumulations where thunderstorms track.

Freezing levels have lowered under the current low to below 8k feet 
along the North Coast while remaining above 11k feet across the 
south. Levels will continue to lower through the weekend to below 6k 
feet across the north on Monday morning and 8k feet across the 
south. 


.METEOROLOGICAL CONDITIONS (LONG TERM: MON AM - THU AM)...

The secondary upr low moving across northern CA will open up and 
shift inland on Monday...bringing remnant showers to the Sierra and 
portions of coastal southern CA from southwest San Bernardino county 
down to the CA/MX border. Amounts in these areas will remain close 
to 0.10-inch or less. The best opportunity for precip will be ahead 
of the s/wv trof axis...over the Humboldt River basin with the 
potential for 0.10- to 0.33-inch over the higher terrain of Elko and 
White Pine counties. Freezing levels will initially be relatively 
low as the core of the system moves overhead...down near 5500-feet 
across northern/central CA into western NV...and then from 6000- to 
7500-feet over eastern NV down to southern CA.

Tuesday will be primarily dry as a quick moving relatively flat upr 
ridge slides over the region ahead of the next system moving from 
the Gulf of Alaska toward the southern BC and the Pacific Northwest 
on Wednesday. There is some discrepancy amongst the 10/00Z models in 
terms of the depth of this system with the GFS and GEM a bit sharper 
with the base of the system moving across northern CA into northern 
NV...while the EC is a bit more shallow. These sharper/deeper 
solutions do drag a bit more light precip across the northern tier 
of the area with the best totals over far northwest CA...the crest 
of the southern OR Cascades...and extreme northern NV. Totals look 
to range from 0.25- to 0.50-inch. Freezing levels will drop down to 
about 3500- to 6000-feet in areas of precip as the base of the 
system moves across the area.


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.