Lafayette, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

912
FXUS66 KMTR 111101
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
401 AM PDT Mon Aug 11 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 333 AM PDT Mon Aug 11 2025

- Moderate HeatRisk continues through Monday for portions of North,
   East, and South Bay counties and interior Monterey and San Benito
   counties.

 - Elevated fire weather concerns persist through Monday given the warm
   and dry conditions combined with breezy afternoon and evening
   winds.

- Pattern change Tuesday, with cooler weather and coastal drizzle
  returning to the forecast.

&&

.SHORT TERM...
Issued at 333 AM PDT Mon Aug 11 2025
(Today and tonight)

The Fort Ord Profiler this morning shows the marine layer around
1400ft this morning, with the spread of the stratus looking to match
a marine layer depth of 1500ft. Stratus should take a touch longer
to erode this morning, especially for those closer to the coast.
Overall, another sunny day is expected for interior locations with
high temperatures peaking 90s, perhaps closer to the upper 90s to
near 105 for interior Contra Costa, San Benitio, and Monterey
counties. Stratus returns tonight and will seep into the valleys

&&

.LONG TERM...
Issued at 333 AM PDT Mon Aug 11 2025
(Tuesday through Sunday)

The pattern change begins on Tuesday, though be it, perhaps a bit
more minimally than previously expected. A shortwave trough
approaches the PacNW which will begin to flatten the upper level
ridge. High temperatures will be a few degrees cooler than Monday,
with the gradual decrease in temperatures continuing throughout the
week. The more substantial trough, kicks in on Wednesday which will
pave the way for upper level troughing to dominate the forecast
through the weekend. Look for cloudy, drizzly, and foggy overnights
and sunny skies for interior locations by the afternoon.

An interesting note in the forecast is that a few deterministic
models are trying to show moisture from Tropical Depression Ivo
being pulled over our coast. CAPE seems to struggle to manifest
given the troughing, but midlevel lapse rates are interesting around
7.5-8C/km. For now current thinking is perhaps we see some cumulus
clouds or perhaps some high level clouds. Thunderstorm development
looks unlikely at this time.

&&

.AVIATION...
(12Z TAFS)
Issued at 358 AM PDT Mon Aug 11 2025

Currently a mixed bag of IFR-VFR at the terminals with a marine
layer of about 1,600 feet. High (80%) confidence in widespread VFR
this afternoon with low stratus sticking close to the coast. Little
change in the overall pattern will yield similar conditions tonight
as what is currently underway.

Vicinity of SFO...Currently IFR with westerly flow. High (90%)
confidence in VFR by the afternoon with moderate (60%) confidence on
an IFR ceiling returning to the terminal tonight. Westerly winds
will prevail through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently IFR with northwesterly flow at
both terminals. High (80%) confidence on brief VFR being achieved
with moderate (50-60%) confidence on IFR ceilings returning to
both terminals tonight.

&&

.MARINE...
(Today through Saturday)
Issued at 333 AM PDT Mon Aug 11 2025

Moderate seas will build to become rough for inner waters and
outer waters Thursday. Northwesterly breezes will be gentle to
moderate through Wednesday with diurnally driven afternoon sea
breezes bringing localized strong gusts through the Delta and
along Point Sur. Northwesterly breezes increase Thursday to
become fresh to strong, posing hazardous conditions for small
craft.

&&

.FIRE WEATHER...
Issued at 906 AM PDT Sun Aug 10 2025

Not much change to the forecast for the next couple of days, with
hot and dry conditions persisting through Monday and breezy and
gusty onshore winds each afternoon and evening, both leading to
curing fuels and the possibility of rapidly spreading fires should
one start. Poor overnight humidity recoveries in the higher
terrain will contribute to the fire weather threats. As an upper
level ridge breaks down, the gusty afternoon winds will linger,
possible through the middle of the upcoming work week. However,
the cooling temperatures and deepening marine layer will help to
mitigate fire weather threats, and by the end of the work week a
trough should bring temperatures below seasonal averages across
the region.

DialH

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 1 PM this afternoon to 11 PM PDT this
     evening for SF Bay N of Bay Bridge.

     Small Craft Advisory from 3 PM this afternoon to 9 AM PDT
     Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Sarment
MARINE...Sarment

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