Russian River Meadows, California Weather Forecast Discussion

063
FXUS66 KMTR 071801
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1101 AM PDT Sun Sep 7 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 1208 AM PDT Sun Sep 7 2025
- Below normal temperatures through the week.
- Chance for light rain Monday through Wednesday.
&&
.UPDATE...
Issued at 958 AM PDT Sun Sep 7 2025
No changes to the forecast this morning. Stratus slowly recedes
across the San Francisco, San Mateo and East Bay counties. Look
for sunny skies across the area later this afternoon.
&&
.SHORT TERM...
Issued at 1208 AM PDT Sun Sep 7 2025
(Today and tonight)
Patchy marine layer stratus is filling in this morning under a
full moon. The pattern today is dominated by the interaction
between weak ridging over northern Mexico and an approaching
trough off the coast. Dry air at 925 mb will gradually filter out
over the next 24 hours, but will continue to impact the low cloud
cover through the majority of the day today. Despite the increased
sunshine, 850 mb temperatures are below normal and will keep
surface temperatures around 5 degrees cooler than normal, similar
to yesterday. Marine layer clouds will roll back in tonight with
more and earlier coverage than the last couple nights as the dry
air filters out.
&&
.LONG TERM...
Issued at 1208 AM PDT Sun Sep 7 2025
(Monday through Saturday)
Monday will bring a significant pattern change. The 500 mb trough
will approach the immediate coast with surface low pressure off
Northern California and an associated cold front extending SW into
the Eastern Pacific. This pattern will bring SW winds and high
moisture ahead of the cold front. As the front moves through and
lifts this air mass, light rain is possible beginning Monday
morning in the North Bay and pushing south through the day. Any
accumulation will be low, with up to 1/10th expected in the North
Bay and only some novelty drops further south. After the front
moves through, 500 mb temperatures will drop to around -15C late
Tuesday, which is in the bottom 10th percentile for this time of
year. It looks like the moisture will survive frontal passage,
and the PW is expected to remain above 150% of normal through
Wednesday. Combined with daytime heating, surface based
instability could be triggered Tuesday through Thursday, with the
best chance Wednesday afternoon. Expect some cumulus clouds, with
an outside chance for showers or thunderstorms. By Thursday the
instability will decrease and shower chances diminish.
&&
.AVIATION...
(18Z TAFS)
Issued at 1046 AM PDT Sun Sep 7 2025
Clearing skies today across the region with only a few high clouds
moving over from the incoming upper level trough. Marine layer
deepens through this evening and tonight leading to good coverage
of marine stratus overnight and coastal drizzle into Monday
morning. High confidence in stratus lingering after sunrise across
the Bay Area.
Vicinity of SFO...Some lingering thin stratus slow to clear this
morning, but overall VFR throughout today with breezy NW winds and
FEW clouds periodically through the day. Moderate confidence in
stratus return timing tonight and lingering beyond sunrise
tomorrow under a very deep marine layer.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Clear as can be this morning and will
remain so through the 00Z hour, beyond which the probability of
MVFR/IFR cigs increases significantly. Slight potential for
coastal drizzle through sunrise Monday morning. Otherwise high
confidence in lingering stratus into mid-morning Monday.
&&
.MARINE...
(Today through Friday)
Issued at 958 AM PDT Sun Sep 7 2025
Gentle to moderate northwesterly breezes will prevail through
Monday. Moderate to fresh northwesterly breezes will prevail
Tuesday and Wednesday with widespread strong gusts. Light rain can
be expected Monday with a nonzero chance for thunderstorms Tuesday
and Wednesday. Moderate seas will prevail through Thursday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Behringer
MARINE...Canepa
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NWS MTR Office Area Forecast Discussion