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CNRFC Hydrometeorological Discussion

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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
715 AM PST Sun Feb 25 2024

...MAINLY DRY ON SUNDAY WITH PRECIP MOVING IN MONDAY...
...LONGER DURATION PRECIP EVENT SETS UP THE SECOND HALF OF WEEK...

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

The upr ridge extending from the Desert Southwest toward southern OR 
and northern CA yesterday is weakening as a s/wv trof moving up and 
over the high pressure over the east-central Pacific is beginning to 
dive toward the southeast from the Gulf of Alaska. Also...to the 
southwest of CA...an upr low continues to wobble between 130W and 
140W at about the latitude of 30N. Dry conditions will persist for 
much of today...but as the two previously mentioned systems approach 
the region...look for the opportunity for precip to increase into 
Monday with the best totals still expected near the CA/OR border 
into northeast NV and along the length of the Sierra as the s/wv 
trof moves from the Pacific Northwest toward the east-southeast 
across the Great Basin before reaching the central Rockies...while 
the upr low weakens and slowly meanders eastward to the coast near 
the CA/MX border. Freezing levels will range from north-to-south 
from about 4500- to 7000-feet. 

Conditions will dry out for Tuesday before the next system moves 
toward the Gulf of Alaska and then digs across the northeast Pacific 
to bring a prolonged period of precip for the second half of the 
week...in particular upslope areas of the northern CA coastal 
mountains and across the southern OR Cascades down to the Shasta 
Lake drainage and much of the Sierra where persistent moist onshore 
west to southwest flow will exist in the low- to mid-levels. 
Moisture isn't expected to be overly abundant with PW values 
generally near and just over 0.75-inch intersecting the 
coast...given the origin of the system to the northwest...it'll just 
be the duration that results in reasonably impressive precip numbers 
by the end of the upcoming weekend. Freezing levels will also drop 
as the cooler airmass moves toward the region...starting out 
Wednesday from about 5500-feet far north and east to about 9500-feet 
for southern CA. By early Saturday...these will have plummeted down 
to about 1500-feet for northwest CA...2500-feet along I-80 in CA 
(higher in NV ahead of the coolest air)...3500- to 5500-feet for 
central CA...and 5500- to 8500-feet across southern CA in southern 
NV.