Valley Ford, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

043
FXUS66 KMTR 060510
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1010 PM PDT Mon May 5 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 920 PM PDT Mon May 5 2025

Warm, dry weather persists through the rest of the week before a
potential upper level trough moves through next weekend, bringing
cooler weather and a chance for light rain.

&&

.UPDATE...
Issued at 937 PM PDT Mon May 5 2025

Winds are still breezy to gusty on a few hill tops and mountain
tops, however for most places winds have eased since earlier today.
The ACV-SFO pressure gradient has decreased to 5.2 mb while juxtaposed
to a strengthening southerly pressure gradient 3.8 mb SBA-SFO and
3.7 mb SMX-SFO. The SFO-SAC pressure gradient is 1.6 mb. Satellite
shows a few patches of stratus and/or fog along the immediate
coastline of the north Central Coast and a few cirrus clouds
arriving from the north, most locations are clear. Average
temperatures were above to well above normal, high temps warmed up
under high pressure and downsloping winds, but fell short of
record high temperatures today at the long term sites. Many record
highs today remain from a 3 to 4 day heatwave nearly centered on
May 5, 1987.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 230 PM PDT Mon May 5 2025

Key Messages:
- Offshore winds diminish through the afternoon/evening
- Winds shift back to onshore everywhere by Tuesday afternoon

Temperatures have soared this morning in part due to strong
northerly winds, clear skies, and a mixed out marine layer. For the
short term forecast, bumped forecast high temperatures up by a few
degrees across the North Bay Valleys and Santa Clara Valleys where
more significant warming already occurred this morning. Temperatures
are already in the low 80s across the North Bay with highs set to
reach the upper 80s across northern portions of Sonoma and Napa.
Offshore winds have started to ease across the North Bay and East
Bay with only a few locations in the higher elevations still gusting
above Wind Advisory Criteria. Thus, the Wind Advisory was allowed to
expire as of 2 PM with the winds expected to continue trending
downwards. Synoptically, the cut-off low to our southeast has
started to weaken and is shifting further east into the
Intermountain West while high pressure builds in more firmly over
California. At the surface, the KSFO-KACV (Humboldt County) pressure
gradient shows that our North-South gradient peaked around 3AM this
morning around -9.50 hPa (strongly northerly) and has diminished to
-6.40 hPa as this afternoon. This gradient is forecast to ease to
around -1.0 hPa (weakly northerly) by early Tuesday morning.
Accordingly, gusts will continue to ease through tomorrow morning
with gusts up to 30 mph expected this evening diminishing to around
15 to 20 mph by tomorrow morning.

Relative Humidity (RH) values are currently between 10 to 25% across
the interior. Overnight humidity recoveries, particularly for the
North Bay and East Bay Hills, will be limited to around 30% tonight
in part thanks to continuing (but easing) offshore winds. Conditions
remain dry on Tuesday with RH values forecast to be in the 25-50%
range. Offshore winds will continue to ease tonight into tomorrow
with winds gradually shifting back onshore by late in the day on
Tuesday. High temperatures on Tuesday will be warm with highs in the
upper 70s to low 80s. We may need to bump forecast high temperatures
up again tomorrow if we see temperatures trending warmer during the
morning hours similar to how they did this morning. As offshore
winds weaken, we will see the return of the marine layer as it
deepens to around 1,000 ft. This will bring stratus back to coastal
areas and bring in cooler, moister air across the area. Fire
concerns remain elevated for the North Bay Interior Mountains
through Monday evening but fuels should be moist enough to alleviate
most concerns. Residents are advised to follow local guidance and if
utilizing an outdoor stove or campfire take caution given the
ongoing breezier winds. Fire weather concerns will diminish
heading into Tuesday as offshore winds ease and gradually
transition back to onshore with daytime/overnight humidity values
improving late Tuesday into Wednesday.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 230 PM PDT Mon May 5 2025

High pressure will persist over the West Coast through the remainder
of the week and into next weekend. Temperatures will briefly cool
down on Wednesday, with highs in the 70s across the interior and 60s
along the coast, as returning onshore flow brings in cooler and
moister air from the west. This cool down is short lived,
however, with Thursday kicking off another warming trend and
temperatures rising back into the 80s across the interior and
staying in the 60s along the coast. The warmest areas will be
southern interior Monterey/San Benito Counties were highs will be
in the low to mid 90s (running between 10 to 15 degrees above
normal). Otherwise, high pressure will keep our weather fairly
quiet this week with winds diurnally breezy (10-20 mph) as the sea
breeze returns each afternoon.

The forecast becomes a bit more uncertain Sunday into
next week with guidance showing an upper level trough dipping into
the Bay Area. CPC guidance is leaning above normal for precipitation
through mid May. That in combination with a potential incoming upper
level low would suggest we have some potential for rain next week.
However, the caveat to this is that May marks the start of our dry
season where essentially any rainfall at all is considered above
normal. Ensemble guidance shows some potential for light rain (at
most a few tenths of an inch) across the region but this is likely
to change as we get closer to next weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 1001 PM PDT Mon May 5 2025

Mostly VFR conditions continue into the night with the exception of
HAF which will have reduced visibilities from sea spray (noted as
HZ). Breezy surface winds linger into the evening before reducing
with some LLWS concerns at STS as aloft stay strong and and
northeasterly. These LLWS concerns ease into the late night as
surface winds aloft reduce. Low clouds creep up the Big Sur Coast
and fill (IFR) around the Monterey Bay into Tuesday morning. These
clouds will also push their way up to HAF into the early morning.
Winds build into the late morning on Tuesday, with VFR returning to
all but HAF. CIGs will slowly move inland into the evening with
the Monterey Bay terminals seeing IFR CIGS in the night.

Vicinity of SFO...VFR through the TAF period. Winds stay moderate
through most of the night and then become light and variable into
early Tuesday. West winds build again into Tuesday afternoon, but
stay mostly moderate. There is some model disagreement of whether
or not the southerly surge patter will introduce more
southwesterly winds from the San Mateo coast, but confidence in
this scenario is low. Regardless, winds look to turn light and
variable into Tuesday night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR lasts into the late night. Winds stay
light and variable through the night. A southerly surge of IFR-
level clouds will move up from the Big Sur Coast and flow around
and fill over the Monterey Bay in the late night. Cloud cover
looks to lift to MVFR levels in the mid morning, but won`t exit
from the terminals until more moderate winds arrive into Tuesday
afternoon. IFR CIGS return into the night as winds reduce.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 1001 PM PDT Mon May 5 2025

Breezy to gusty winds linger in the northern outer waters as winds
elsewhere ease. Seas will also reduce into the night with a
moderate northwest swell expected through the week. Breezier winds
build again in the later work week and look to last through the
rest of the forecast period.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Gale Warning until 9 AM PDT Tuesday for Pt Arena to Pt Reyes 10-
     60 NM.

     Small Craft Advisory until 3 AM PDT Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Murdock
MARINE...Murdock

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