Version:  Current  |  Back 1  |  Back 2  |  Back 3  |  Back 4  |  Back 5  |
Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
645 AM PDT Mon Apr 20 2026

...COOLER AND UNSETTLED THROUGH WEDNESDAY...
...BEST PRECIP ANTICIPATED OVER NORTHERN/CENTRAL CA...

.METEOROLOGICAL CONDITIONS (MON AM - SUN AM)...

A disturbance that moved off the Aleutian Islands last weeks has 
shifted to the southeast and settled just west of the northern CA 
coast generally just outside of 130W this morning. Slower model 
solutions were definitely the way to go with the progression of this 
system toward the west coast and eventually as it spreads inland for 
the middle of the week. Radar imagery shows the leading edge of the 
precip making its way onshore with a band of precip along coastal 
sections between the Golden Gate and CA/OR border. So far...precip 
gauges overnight have recorded anywhere from 0.01- and 0.33-inch 
with the greatest amounts over the King Range located on Cape 
Mendocino.

Through today...look for the upr low to slowly make its way eastward 
and move within 130W overnight...continuing to spread precip inland 
across much of northern CA and reaching back across the Monterey Bay 
area. Overall totals will generally range from 0.50- to 1.00-inch. 
Then into tomorrow...the system will increase its forward speed and 
shift inland across northern CA. This will bring an area of 
widespread precip across northern/central CA reaching past the crest 
over northern/central NV. Best totals will fall over the length of 
the Sierra with 1.00- to 2.00-inches possible. Also...SPC is 
painting an broad area of general thunderstorms across much of 
northern and central CA on Day 2...which covers the period from 
Tuesday 12 UTC through Wednesday 12 UTC. Convective cells could 
result in localized heavier precip amounts.

Wednesday will see lingering precip across the northern half of the 
area as cyclonic flow continues over the region. Best totals will 
continue to be over upslope portions of the northern/central Sierra 
with another 0.10- to 0.33-inch anticipated. Then Thursday will be a 
general dry day before a disturbance moving across the Pacific 
toward the central/southern CA coast possibly moves close enough to 
bring scattered light precip later Friday through Saturday. Overall 
totals at this point do not look overly impressive.

Freezing levels will bottom out as the core of the cooler airmass 
moves across northern/central CA toward northern NV late Tuesday 
into early Wednesday...dropping down to 5000- to 6500-feet. These 
will rebound as the upr low shifts east.


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.