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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
655 AM PST Thu Feb 5 2026

...WEAK SYSTEM IMPACTS SOUTHERN AREAS ON FRIDAY...
...HIGH PRESSURE BREAKS DOWN WITH FIRST SYSTEM ACROSS NORTHERN AREAS 
ON SUNDAY...

.METEOROLOGICAL CONDITIONS (THU AM - WED AM)...

Another day of unseasonably warm temperatures expected across CA and 
NV this Thursday with anomalies of plus 10- to plus 20-degF expected 
for most locations. This is a result of strong high pressure 
continuing to be locked in across the western US with the core of 
this feature shifting a bit more inland across northeast NV. This 
will also bring dry conditions to the region through sunset.

Late tonight into early Friday...a weak upr low just west of central 
Baja near 30N/120W and an elongating and splitting s/wv trof 
rotating northeast through the broad east-central Pacific upr trof 
will phase. After this occurs...look for this weak disturbance to 
start to drift southeast just off the central and southern CA coast 
through Friday and Saturday before reaching central Baja early on 
Sunday. Given the trajectory and just enough moisture...models 
continue to depict scattered showers developing across the southern 
Sierra (mainly from the Tuolumne River basin southward) and portions 
of southern CA and extreme southern NV on Friday. Amounts should be 
generally near 0.10-inch or less...except along the crest of the 
southern Sierra where totals could range from 0.10- to 0.25-inch. 
Given the location of the upr low on Saturday...it appears to be too 
distant to bring any lingering precip.

Across the rest of the area on Saturday...the upr ridge will 
continue to hold on strong...but become rather positively tilted 
stretching from northern/central CA northeast toward the northern 
Rockies. This will initially keep a fetch of moisture that advects 
from near Hawaii to the northeast to the north of the 
region...intersecting the Pacific Northwest coast with round one of 
precip. As the upr ridge finally loses the battle on Sunday and is 
pushed downstream of the area...a relatively weak s/wv trof will 
make its way toward the Pacific Northwest and northern CA...pushing 
a frontal boundary south along the coast along with the narrowing 
moisture plume. Expected precip for Sunday looks relatively similar 
to yesterday/s forecast with the best totals over the lower Klamath 
and Smith River basin (0.50- to 1.50-inches) and then dropping off 
south and inland. The southern extent should reach to near Point 
Arena for coastal locations and the Feather/Yuba River basins across 
the northern Sierra. Freezing levels look similar to yesterday/s 
thinking as well...from 9000- to 11000-feet for I-80 northward to 
start Sunday...and then approx 4500- to 8000-feet after frontal 
passage.

Things become a bit mottled for the early portion of the next work 
week as the eastern Pacific becomes a bit more active with several 
disturbances moving through the flow. The 05/00Z EC shows a bit more 
definition to a s/wv trof moving across CA and NV...while the GFS is 
weaker. The CMC leans a bit more toward the EC solution for Monday 
and Tuesday. At this time...leaned on a blend of the global models 
along with incorporating the 05/13Z NBM. This would bring scattered 
light precip to much of the region with coastal areas of 
northern/central CA...the length of the Sierra and portions of 
northeast NV between 0.10- and 0.33-inch. Freezing levels will 
continue to drop as colder air advects across the entire area with 
4000-feet north and 7500-feet south by the end of the forecast 
period.


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.