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AGUS76 KRSA 071454
HMDRSA

Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
700 AM PST Fri Nov 7 2025

...LINGERING LIGHT SHOWERS INTO MID MORNING FOR PARTS OF N CA/NV
BEFORE DRY CONDITIONS RETURN THROUGH TUES AS HIGH PRESSURE BUILDS...
...MODELS PREDICT A LARGE UPPER LOW BRINGING MORE WIDESPREAD PRECIP
SOME TIME MID TO LATE NEXT WEEK...

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

Another about 0.50-1" of precip fell along the north coast and into
Shasta over the past 24 hours as that second surge of moisture moved
in. Radar has a few lingering showers over nrn NV and nrn CA this
morning as high pressure continues to build in offshore. Only
anticipating another few hundredths of an inch or so of scattered
showers for parts of nrn CA/NV into mid morning before dry
conditions return and stick around at least through Tuesday. In
addition to dry weather, expect widespread above normal temperatures
with anomalies of +5 to +15 deg F after today. Some areas may hit
+20 deg F. The next precip maker is expected mid to late next week
in the form of a large surface/upper low forming off a system in the
Gulf of Alaska. The ensemble means of the GEFS and the EPS have
about 500 kg/ms IVT reaching the coast from this system with traces
going up to about 700.

The real point of disagreement here is the arrival timing. Some
ensemble members show showers moving inland as early as Wednesday
afternoon while others hold off until Thursday afternoon/evening.
Looking at the ensemble QPF clusters about 80% of the overall
membership (GFS/ECMWF/CMC) hold off until at least 00z Thursday for
anything other than lighter showers. The other 19%, which is mostly
the CMC at 70% of its members, have over 1.50" along the north coast
and spread precip as far south as the Big Sur coastal mountains. The
det GFS brings in initial showers into Thursday morning while the
ECMWF starts late Weds afternoon. Looking at the ensemble members of
the ECMWF AIFS the majority agree on waiting until after 00z Thurs
while the rest show a range of precip from a trace to nearly an inch
at Arcata. For the official forecast, blended in the morning WPC
guidance with the 50% NBM in the 18z-00z window to bring in some
light showers to parts of the coast while slowing down the timing.
Precip is then expected to spread inland and south across the
central coast into the evening. Impacts from this low will continue
Friday as well but this falls outside our six day period.

To summarize, high pressure to return dry conditions and seasonably
warm temperatures to the region later today through early next week.
Then a low will bring back more widespread precip mid to late week.
QPF was generally a blend of WPC guidance and the NBM. Amounts are
looking like 0.30-0.75" along the coast north of the Golden Gate
(locally 1" King Range), tapering off to 0.10-0.50" inland to I-5
and a few hundredths to 0.25" for the rest of the central coast.
Confidence is low given model differences and ensemble spread,
expect these amounts to change over the coming issuances.

Freezing levels still look relatively high for the start of this
system with the region generally above 11 kft and up to 13.5 kft
through the southern Sierra.


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



AS

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