Windsor, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

087
FXUS66 KMTR 100355 AAA
AFDMTR

Area Forecast Discussion...UPDATED
National Weather Service San Francisco CA
855 PM PDT Wed Apr 9 2025

...New UPDATE...

.SYNOPSIS...
Issued at 122 PM PDT Wed Apr 9 2025

Warm and dry conditions continue through the forecast period.

&&

.UPDATE...
Issued at 855 PM PDT Wed Apr 9 2025

The inherited short term forecast is in good shape with no
changes needed for this evening. Largely quiescent conditions are
anticipated to unfold across the Bay Area and Central Coast as
synoptic scale subsidence continues to dominate the weather this
evening. Comparisons of our 12 UTC/00 UTC weather balloon data
from the Oakland airport reveals further drying of the lower
troposphere. With our precipitable water (a good proxy for total
atmospheric moisture) continuing to fall (now at 1/2 inch), this
will curtail the fog potential across the region tonight. Similar
to last night, locations in valleys, particularly those near
rivers, lakes, or reservoirs will stand the best chance for
reduced visibility. We`ll continue our mini-warming period with
"minor" HeatRisk anticipated for portions of the area through the
end of the week.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 122 PM PDT Wed Apr 9 2025

The region will feel the maximum effects of the longwave ridge today
as the axis is overhead. I opted to abandon the NBM/NBM50 strategy
that was used and discussed yesterday and instead just roll with the
deterministic NBM, here`s why. For starters and most importantly,
the National Weather Service is impacts based. Our messaging of
minor HeatRisk does not change whether the maximum temperature is 76
degrees or 79 degrees. A look under the hood of the deterministic
NBM versus the probabilistic NBM reveals that the former allows for
a quicker response to changing weather patterns while the latter
runs warm leading into warm seasons and cold leading into cold
seasons. Being in the shoulder season of Spring between Winter and
Summer, it is likely that the probabilistic NBM is running warm.
The HREF depicts that it is likely (60%-80%) that low clouds will
return to coastal and valley locations overnight. Being under an
area of high pressure and thus subsidence, this promotes a
compressed/shallow marine layer which will result in both lower
ceilings and visibilities, but it also means that it won`t be deep
enough to penetrate too far inland.

NWS Minor HeatRisk:

- Heat of this type is tolerated by most; however there is a minor risk
  for extremely heat-sensitive groups to experience negative
  heat- related health effects.

- The risk is primarily for those who are extremely sensitive to heat,
  especially when outdoors without effective cooling and/or
  adequate hydration.

- Very common heat.

- For those at risk, actions that can be taken: increase
  hydration, reduce time spent outdoors or stay in the shade when
  the sun is strongest, and open windows at night and use fans to
  bring cooler air inside buildings.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 122 PM PDT Wed Apr 9 2025

Thursday begins the cooldown as heights begin to ever so slightly
fall as an upper-level shortwave trough in the Pacific Northwest
nudges the ridge to the east. A surface low in British Columbia and
its attendant weak, dry cold front will sweep through the region
on Friday bringing with it an increase in northerly winds,
particularly over the marine zones. There`s even the chance for
Oakland Museum (OAMC1) to challenge the daily minimum temperature
forecast Saturday morning, the forecast is 48 degrees with the
previous record of 45 degrees set in 2001. There`s good agreement
in the clusters through Saturday, but that`s where it ends. By
Sunday, it is likely (83%) that a shortwave trough will undercut
the shortwave ridge resulting in split flow over the region. The
lack of confidence comes from the location and amplitude of these
features. This compounds in the following days as the progression
of the longwave pattern becomes uncertain. Nonetheless, there`s
still no rainfall or widespread impacts aside from minor HeatRisk expected
through the forecast period.

&&

.AVIATION...
(00Z TAFS)
Issued at 611 PM PDT Wed Apr 9 2025

Widespread VFR lasts into the late night. Winds stay moderate to
breezy before easing in the late evening and early night. IFR CIGs
build along the coast into the late night and slowly move inland
into Thursday morning. In addition to CIGs, the North Bay terminals
look to see moments of fog into the mid morning. Cloud cover and fog
erode into the late morning and into Thursday Afternoon as more
moderate winds arrive.

Vicinity of SFO...VFR lasts into early Thursday. Expect winds to
reduce and become more moderate through much of the night. IFR CIGS
build over the terminal Thursday morning. These CIGs dissipate in
the late morning ahead of more breezy west winds building that
afternoon.

SFO Bridge Approach...IFR CIGs build slightly later than SFO into
Thursday morning.

Monterey Bay Terminals...Winds weaken into the late evening and stay
light through the morning. IFR CIGs arrive early Thursday and last
into the late morning. Moderate west winds build for Thursday
afternoon.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 611 PM PDT Wed Apr 9 2025

High pressure offshore will keep northerly winds over the waters
for much of the forecast. A coastal jet will result in locally
stronger winds for areas south of Point Sur. Expect a gradual
improvement of the sea state as swell heights subside through
midweek. Winds increase late this week and a larger swell will
rebuild this weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Thursday to 3 AM PDT Friday for
     Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

UPDATE...Bain
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Murdock
MARINE...Murdock

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