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Hydrometeorological Discussion
National Weather Service / California-Nevada RFC / Sacramento CA
710 AM PST Sun Nov 1 2026

...PRECIP ACROSS EASTERN NV AND PORTIONS OF SOCAL WRAP UP TODAY...
...WEAK SYSTEM TRAVERSES NORTHERN CA AND NORTHERN NV ON TUE...
...DRY CONDITIONS RETURN TO END THE WEEK...

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

Troffing along the west coast is beginning to shift inland this 
morning with the deep northern s/wv trof moving across the southern 
Sierra...while the southern energy is approaching the northern Baja 
coast. A rather deep moisture plume with origins in the lower 
latitudes generally between 120W and 130W has been drawn northward 
ahead of this overall troffing...and is advecting inland over 
northern Baja on its way toward the Desert Southwest. CIMMS TPW 
imagery shows values within this plume exceeding 2.00-inches as it 
reaches the coast...while the 01/00Z GFS and EC both show a maximum 
IVT close to 1200-kg/m/s along the Baja coast. This stream of 
moisture interacting with the favorable forcing as the troffing 
shifts inland is generating moderate to heavy precip downstream of 
the area across AZ up into UT and CO. The western edge of the 
elevated moisture will bring light to moderate precip from eastern 
NV southward across portions of southern CA with anywhere from 0.50- 
to 1.00-inch possible mainly through the afternoon hours. So far in 
the past 3-hours since 01/12Z...the KIPL automated observation 
station has seen 0.49-inch...as radar imagery shows echoes streaming 
from southwest to northeast across these desert locations close to 
the lower Colorado River basin.

Precip will diminish this evening and overnight as the upr trof 
slides to the east and a transitory upr ridge slides across the area 
on Monday. This will bring dry conditions for Day 2. Then attention 
next turns to a s/wv trof moving across the eastern Pacific 
generally along 40N...now just passing 150W. Models have struggled a 
bit with this feature...but are starting to grasp the timing and 
coverage of precip anticipated for Tuesday...which is a tad faster 
than yesterday/s thinking. Precip will spread across northern CA as 
the system moves inland and then weaken as it shifts inland across 
northern NV. A narrowing PW plume ahead of this feature will bring 
values close to 1.00-inch to the coast between Cape Mendocino and 
the SF Bay Area before quickly eroding as it shifts inland. Best 
precip will fall across the Eel and Russian River basins with 
amounts of 0.10- to 0.33-inch...dropping off to 0.25-inch or less 
for the Shasta Lake drainage and northern Sierra. The Sacramento 
Valley...SF Bay Area...and central Sierra should all remain near or 
less than 0.10-inch.

This s/wv trof will quickly move off toward the east and reach the 
central Rockies by Wednesday. Another weak disturbance that was 
initially thought to reach far enough south to bring far northern CA 
and northern NV some light precip on Wednesday into Thursday is now 
looking to remain too far north with dry conditions returning to the 
area for the latter half of the week. High pressure will slowly 
build across the west coast to end the week. 


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.