Idria, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

819
FXUS66 KMTR 221123
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
423 AM PDT Thu May 22 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 238 AM PDT Thu May 22 2025

Elevated fire weather conditions remain the primary concern today as
warm, dry, and windy conditions continue.

&&

.SHORT TERM...
(Today and tonight)
Issued at 238 AM PDT Thu May 22 2025

The marine layer is being observed at 800 feet by the Fort Ord
profiler with satellite just starting to show some stratus forming
over Tomales Bay and along the San Francisco Peninsula Coast.
Despite this, the 00Z KOAK sounding revealed a LowRH (surface-850
mb) value of 25%, a MidRH (850mb-650mb) value of 9%, and a
precipitable water value of 0.45 inches which is slightly above the
10th percentile of 0.42 inches for 00Z May 22nd. An upper-level
shortwave trough will skirt the region today, bringing temperatures
back down to seasonal normals. Of more impact will be the strong
onshore winds that it brings with gusts of 25-35 mph expected over
the waters, along the immediate coastline, through
northwest/southeast oriented valleys, and in the higher terrain.
These winds in conjunction with poor relative humidity (both
overnight recovery and daytime minimum) will continue to support
elevated fire weather conditions.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 238 AM PDT Thu May 22 2025

An approaching second, deeper upper-level shortwave trough will
deepen the marine layer and finally ease fire weather concerns for
the time being as excellent relative humidity recovery (70%+)
returns to all but the highest terrain of the Central Coast.
Sensibly, temperatures will drop to 5 degrees below normal, dubbing
tomorrow the coolest day of the week. Heights will begin to build
and temperatures rebound to seasonal normals Saturday as a
positively tilted upper-level longwave ridge builds into the West.
Due to the orientation of the upper-level pattern, the warmest day
for the Bay Area will be Saturday with the Central Coast having to
wait until Sunday to achieve that feat. The unofficial start of
Summer (Memorial Day) will feel anything but with below normal
temperatures brought to you by a dry cold front. The previously
mentioned upper-level longwave ridge will build and broaden across
the Western two-thirds of CONUS with an upper-level shortwave trough
likely to undercut it, resulting in split flow and unimpactful
weather for our region Tuesday and Wednesday.

&&

.AVIATION...
(12Z TAFS)
Issued at 416 AM PDT Thu May 22 2025

VFR is expected to prevail with a dry airmass across our region in
place. Local geographic effects are responsible for low stratus
in the vicinity of the Monterey Bay terminals.

Vicinity of SFO...VFR is expected to persist through the day and
evening hours with a chance of MVFR/IFR cigs late in the forecast
period for early Friday. Confidence is too low for mentioning in
the TAF attm. Gusty onshore winds will develop this afternoon and
persist until after midnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR/IFR cigs early this morning due to
local effects from an otter eddy in Monterey Bay. Short term
guidance suggests that the low stratus will lift after 15z this
morning and remain VFR until after midnight, when there is a
chance for MVFR/IFR cigs developing in the early morning hours
Friday.

&&

.MARINE...
(Today through Tuesday)
Issued at 416 AM PDT Thu May 22 2025

Widespread hazardous marine conditions continue today as strong
northwesterly breezes with near gale to gale force gusts and rough
seas persist. Fresh to strong northwesterly breezes and moderate
to  rough seas will prevail Friday through Monday.

&&

.FIRE WEATHER...
Issued at 238 AM PDT Thu May 22 2025

The combination of poor daytime relative humidity of 15-25% and
onshore winds with gusts of 25-35 mph along the immediate coastline,
in northwest/southeast oriented valleys, and in the higher terrain
will continue to support elevated fire weather conditions today. The
greatest period of concern is today in cured grass areas. Remain
fire wise and do not be the reason for fire starts.

Sarment

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt
     Pinos 0-10 nm-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 Reyes to
     Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

     Small Craft Advisory from 9 AM this morning to 3 AM PDT Friday
     for Mry Bay.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Pinos
     to Pt Piedras Blancas 0-10 nm.

     Gale Warning from 3 PM this afternoon to 9 PM PDT this evening
     for Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...JM
MARINE...Sarment

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