Lytton, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

079
FXUS66 KMTR 050000
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
500 PM PDT Mon Aug 4 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 322 AM PDT Mon Aug 4 2025

 - Elevated breezes across channels, gaps, passes, and across the
   marine environment today.

 - Elevated fire weather threat for wind corridors and portions of
   the Santa Lucia Range through Monday and again late this week.

 - Subtle warming trend expected through midweek with pockets of
   moderate HeatRisk across far interior locations.

&&

.SHORT TERM...
Issued at 1258 PM PDT Mon Aug 4 2025
(This evening through Tuesday)

Wall to wall sunshine across the forecast area this afternoon. Not
even any pesky lingering stratus along the coast. Increased
sunshine and lack of a noticeable marine layer has led to warmer
24 hour trends. One thing that hasn`t changed since yesterday are
the winds. Onshore flow remains, which is resulting in another
breezy day around the region. While slightly less than Sunday
still seeing some gusts 25-40 mph. The biggest weather impact in
the near term will be elevated fire weather conditions with
breezy onshore, lower humidity, and dry grasses.

Tonight through Tuesday...Another night with a broken up marine
layer or patchy stratus. Would not be surprise to see a few
interior locations dip into the 40s again for temps thanks to
clear skies and sheltered winds. The subtle warming trend noticed
today will continue on Tuesday as the temperatures creep up a few
more degrees. Highs will be in the 60s/70s coast and mid 70s to
lower 90s interior. Onshore flow will remains, but winds will be
weaker than Monday and over the weekend.

&&

.LONG TERM...
Issued at 135 PM PDT Mon Aug 4 2025
(Tuesday night through next Sunday)

Long term forecast will feature a more compressed marine layer
with warmer temperatures. While the longwave pattern this week
doesn`t scream heat it does show higher 500mb heights and warmer
850mb temperatures. Those two items are usually good indicators
of warmer weather on the way.

No big changes to previous forecast. Daytime highs will increase
3-5 degrees through Thursday before peaking Thursday/Friday and
then gradually moderating through the weekend. That being said,
onshore flow remains, which will keep the coastal areas much
cooler than the interior. In other words, bigger temperature
spread across the forecast area. More 60s/70s along the coast,
but far interior locations will soar into the 90s and even crack
100 in the warmest locations. The warmer temperatures will nudge
HeatRisk upward, but still mainly Minor to Moderate. The warmer
airmass will also make the thermal belts more noticeable at night
with the hills staying in the 60s and 70s.

&&

.AVIATION...
(00Z TAFS)
Issued at 444 PM PDT Mon Aug 4 2025

VFR conditions across the board this afternoon with strong onshore
winds. The winds should decrease a couple hours earlier than
yesterday with calmer conditions overnight. There is a high
probability that the North Bay will stay clear overnight, with
less confidence further south.

Vicinity of SFO...Strong onshore winds are the biggest impact this
evening. There 06Z TAF is holding steady with improvement
beginning around 04Z as the atmosphere starts to decouple,
although the PGE-WRF 2km cross section shows 45 kt winds at Mt.
San Bruno wont decrease until 06Z. There are a few thin clouds
banked up on the windward side of the Peninsula, but otherwise
clear skies in all directions. While probabilistic guidance
suggests anywhere from a 20-40% chance of ceilings overnight, the
current satellite image and persistence forecast suggest they will
hold off through the TAF period. I added a scattered group
starting at 11Z to highlight the possibility.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...While the skies are currently clear,
current model guidance and the persistence forecast suggest at
least a few hours of IFR ceilings will develop early Tuesday
morning before clearing in the late morning.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 444 PM PDT Mon Aug 4 2025

Gusty northwest winds will persist tonight into Tuesday. Winds
will be locally stronger along the coast north of Point Reyes,
south of Pigeon Point into Monterey Bay and south of Point Sur
where a few gale force gusts are possible this evening. Seas will
remain moderate to rough through the week.

&&

.FIRE WEATHER...
Issued at 1155 AM PDT Sun Aug 3 2025

The fire weather threat will elevate this afternoon. Fires are
likely to be limited to the grass/brush fuel types and for a few
hours this afternoon, there could be some sites that flirt with or
briefly exceed our RFW matrix/criteria. The period with peak
winds should coincide with an increase in RH, though portions of
the East Bay Hills and lower elevations of the Santa Lucia Range
will likely see RH between 20 and 30 percent as the winds ramp up
this afternoon. Overnight RH recovery will remain poorest across
the higher reaches of the Santa Lucia Range, Santa Cruz Mountains,
Gabilan Range, and Eastern Santa Clara/East Bay Hills with values
between 20% and 40%. Elsewhere, RH should rebound above 50%. As
our subtle warming trend peaks later this week, with above normal
warmth returning in the days 8 to 14 range, we`ll see the fire
weather threat elevate again. Of particular note will be energy
release components approaching the 90th percentile for the Mid-
Coast to Mendocino predictive service area (North Bay) later this
week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-SF Bay N of Bay Bridge.

     Small Craft Advisory until 3 PM PDT Wednesday for Pigeon Pt to
     Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to
     Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PDT Tuesday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM Tuesday to 5 AM PDT Wednesday for
     Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for Pigeon Pt
     to Pt Pinos 0-10 nm.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Flynn
MARINE...Canepa

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