051
AGUS76 KRSA 031456
HMDRSA

Hydrometeorological Discussion
National Weather Service / California-Nevada RFC / Sacramento CA
800 AM PDT Thu Sep 3 2026

...COLD FRONT CONTINUES TO SLOWLY DROP SOUTH OVER NORTHERN CA...
...SHOWERS POSSIBLE FOR SOUTHERN CA AND SOUTHERN NV THIS WEEKEND...

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

An upr low continues to spin just west of the mouth of the Columbia
River this morning...while a sfc cold front extends from the
interior of the Pacific Northwest back southwest across northern CA
before reaching offshore just north of the SF Bay Area. The moisture
plume entrained ahead of the frontal boundary continues to show a
healthy amount of moisture aimed at the SF Bay Area with peak values
just shy of 1.50-inches offshore...while the 03/12Z KOAK RAOB
indicates 1.21-inches of PW. For the most part...radar imagery along
with automated gauge reports show mainly light precip impacting the
higher terrain of northern CA. Best precip today is anticipated to
be in the vicinity of the now slow moving cold front...especially
upslope locations of the northern Sierra where 700-mb winds are
expected to be from the southwest anywhere from 30- to 40-kt.

By Friday morning...the moisture plume will continue to erode as it
slowly makes its way near Point Conception ahead of the sfc cold
front. Precip is expected to dissipate before reaching central CA
with some lingering light amounts over the central Sierra up into
northwest NV early on in the period.

For the upcoming weekend...attention shifts toward southern CA. As
now Hurricane Marie makes its way toward the west-northwest south of
25N...moisture entrained into this system will advect northward
toward southern CA and the lower Colorado River basin. Each
successive model run appears to be less aggressive in precip
development across southern CA with the latest forecast showing
light amounts between Los Angeles and San Diego stretching inland
over the southeast CA deserts and extreme southern NV. Totals are
currently looking to run anywhere from a few hundredths of an inch
up to about 0.33-inch over the southern CA coastal mountains.

Also...the persistent upr low off the Pacific Northwest coast will
finally rotate inland and shift off toward the northeast and reach
the northern Rockies on Monday into Tuesday. This will weaken the
overall cyclonic flow over the west coast. There is disagreement
with how close to the coast the next system diving toward the region
from the northwest will get with the GFS basically right along the
coast and the EC more offshore. This will determine how cool the
region remains...or if temperatures finally start to rebound closer
to normal for this time of year.


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.

QPF graphics are available at www.cnrfc.noaa.gov/qpf.php



DRK

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