Santa Venetia, California Weather Forecast Discussion

054
FXUS66 KMTR 072331
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
431 PM PDT Sun Sep 7 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 259 PM PDT Sun Sep 7 2025
- Below normal temperatures through the week.
- Chance for light rain Monday through Wednesday.
&&
.SHORT TERM...
Issued at 259 PM PDT Sun Sep 7 2025
(This evening through Monday night)
High clouds are flitting in from the upper level low pressure system
that will eventually bring rain chances to the Bay Area, and perhaps
parts of the Central Coast. Until that arrives, the main story for
tonight will be the return of the stratus. The marine layer is
poised to deepen to about 2500ft or so, which should allow for an
earlier onset of stratus for coastal locations. It will then seep
inland, leaving a good portion of the interior blanketed in stratus
by early morning. Coastal drizzle will be possible as well.
Eventually, stratus should clear for interior locations by late mid
to late morning. The aforementioned upper level low will creep
towards West Coast, which will bring an additional influx of high
clouds to the region.
The question then becomes, when will it rain? Latest NBM guidance is
a bit aggressive with the front and has chances arriving mid to late
morning. The more likely period will should be Monday afternoon and
evening for North Bay counties. Elsewhere chances increase late into
the evening, spreading as far south as northern Monterey and San
Benito counties. Confidence for measurable rain remains in highest
for the North Bay, where they could see up to 0.15" of rain. The
farther south you move into the Bay Area, chance decrease to maybe
0.05" or less whereas the Central Coast outside of the Santa Lucia
may see a few hundredths if the front makes it that far.
&&
.LONG TERM...
Issued at 259 PM PDT Sun Sep 7 2025
(Tuesday morning through next Saturday)
Upper level troughing dominates much of the period, leaving us with
unseasonably cool and potentially unsettled weather. Similar
thinking to the midshift and that we could see post frontal
convection Tuesday afternoon and evening, as the cold upper level
low moves inland. Cold air aloft, -15C at 500mb heights, daytime
heating with a couple hundred J/kg of CAPE, mediocre lapse rates of
6.5-7C, and some shear we should at least see some cumulus clouds
form. Showers are not out of the question given PWATS should we get
enough lift. A few rumbles of thunder are possible as well,
currently favoring the far northeastern Sonoma and northern Napa
counties.
The slow slowly meanders eastwards, Wednesdayh into Thursday with
showers retreating to the the terrain and perhaps North Bay counties
on Thursday. Weak upper level ridging should build in for Friday,
leaving us with drier and a hair warmer.
&&
.AVIATION...
(00Z TAFS)
Issued at 430 PM PDT Sun Sep 7 2025
Currently VFR at all terminals. High confidence in sub-VFR ceilings
returning to all terminals tonight with IFR for coastal terminals
and MVFR for bayshore and interior terminals. Widespread VFR is
expected by tomorrow afternoon. An approaching low pressure system
will have high clouds lower through the TAF period with rain
showers likely after the 24 hour TAF period.
Vicinity of SFO...Currently VFR with westerly flow. High confidence
in an MVFR ceiling returning to the terminal tonight. Westerly winds
will prevail through the TAF period.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Currently VFR with westerly flow at MRY and
VFR with northwesterly flow at SNS. High confidence in IFR ceilings
returning to the terminals tonight.
&&
.MARINE...
(Tonight through next Friday)
Issued at 259 PM PDT Sun Sep 7 2025
Moderate northwesterly breezes continue through the early portion
of the week. Winds increase through mid-week as fresh breezes with
strong gusts across the coastal waters. Light rain is anticipated
Monday over the northern waters, and Monday night into Tuesday
across the rest of the waters.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...KR
LONG TERM....KR
AVIATION...Sarment
MARINE...Behringer
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NWS MTR Office Area Forecast Discussion