Fulton, California Weather Forecast Discussion

306
FXUS66 KMTR 070821
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
121 AM PDT Sun Sep 7 2025
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1208 AM PDT Sun Sep 7 2025
- Below normal temperatures through the week.
- Chance for light rain Monday through Wednesday.
&&
.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...
(06Z TAFS)
Issued at 933 PM PDT Sat Sep 6 2025
Currently a mixed bag of IFR-VFR at the terminals with stratus
beginning to develop. Generally drier conditions than 24 hours ago
with a ribbon of dry air moving into the area is leading to low to
moderate confidence on sub-VFR ceilings returning to all terminals
tonight with greatest chances generally at bayshore and coastal
terminals. Winds will be light and variable overnight. Widespread
VFR by tomorrow afternoon.
Vicinity of SFO...Currently VFR with westerly flow. Moderate
confidence on an MVFR ceiling developing tonight. Westerly winds
will prevail through the TAF period.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Currently VFR with southerly flow at MRY
and VFR with northerly flow at SNS. Low to moderate confidence on
IFR ceilings developing at the terminal tonight. Brief VFR will
prevail by tomorrow afternoon with an early return of MVFR ceilings
tomorrow night.
&&
.MARINE...
(Tonight through next Friday)
Issued at 933 PM PDT Sat Sep 6 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 Wednesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Sarment
MARINE...Sarment
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NWS MTR Office Area Forecast Discussion