Santa Clara, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

099
FXUS66 KMTR 111455
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
755 AM PDT Fri Apr 11 2025

...New UPDATE...

.SYNOPSIS...
Issued at 258 AM PDT Fri Apr 11 2025

Gradual cooling today and tomorrow before more widespread minor
HeatRisk returns on Sunday into the beginning of next week.

&&

.UPDATE...
Issued at 740 AM PDT Fri Apr 11 2025

Satellite shows mostly high clouds moving through our area. With
the lack of a strong marine layer, inland temperatures are
already reporting 3-6 degrees warmer than yesterday morning.
Otherwise, pretty much quiet weather today, as the forecast
remains on track for a slight cool down today.

&&

.SHORT TERM...
(Today and tonight)
Issued at 258 AM PDT Fri Apr 11 2025

High clouds streaming northeast across our area overnight on the
backside of the flattening ridge to our east, indicate some cloud
top cooling associated with weak lift from an elongated trough
developing to our west. 00z KOAK sounding showed dry air from the
surface up to 15kft. Decided against adding mentionable PoPs,
thinking the dry air is too much to overcome attm. KMRY surface
observation dropped a couple of degrees as soon as there was a break
in the high cloud cover around 2AM PDT. Overall adjusted this
mornings low temperatures up slightly to account for the lack of
radiational cooling with the mid/high level clouds that will be over
our area by sunrise. This complicates the extent of fog/drizzle that
was expected this morning. Can`t rule out some marine layer drizzle
along the coast, but confidence is low with the high clouds moving
in. Temperatures this afternoon in our coastal areas will be right
around normal, in the low to mid 60s. Inland temperatures will be 5-
10 degrees warmer than normal, with the warmest spots in the
southern valleys of Monterey County, that will climb into the mid
80s.

HiRes short term guidance does suggest that the marine layer will be
more robust tonight into Saturday morning with the potential for
low stratus with fog/drizzle, however more interference from the
presence of mid/high level cloud cover is possible once again.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 258 AM PDT Fri Apr 11 2025

A cool and dry airmass is still on schedule to arrive with the
secondary trough pushing a weak backdoor cold front south through
our area Saturday night into Sunday. Weekend overnight low
temperatures will be on the cool side before warming up nicely in
the afternoon under increasing sun angle. As the backdoor cold front
pushes south through our area during the day Sunday we`ll see a
return of minor HeatRisk inland as temperatures climb above normal
once again. Weak offshore flow will hold the marine layer at bay as
drier air scours south for Sunday and Monday. HiRes guidance does
indicate that the marine layer may hold on strong enough around
Monterey Bay late Saturday into Sunday morning, however confidence
is low attm given the weak forcing associated with an elongated
trough splitting from the polar jet over the weekend, as a cut off
low develops over the waters off of SoCal. Otherwise expect pleasant
temperatures and plenty of sunshine inland through the extended
forecast, and more seasonal temperatures with some pockets of night
time stratus possible along the coast.

&&

.AVIATION...
(12Z TAFS)
Issued at 418 AM PDT Fri Apr 11 2025

Mix of cloud conditions this morning as a weak elevated front
moves through, resulting in a difficult forecast this morning.
Several terminals have seen a mix of VFR and periodic LIFR cigs
this morning. With the front pushing through the Bay Area as of
this issuance, expecting any remaining cigs to gradually lift
and/or become more mixed out with ample dry air in the mid-levels.
The exception will be terminals along the coast where a more
prominent marine layer exists, thus higher confidence that
IFR/LIFR cigs may persist a bit longer. Gusty NW winds behind the
front will likely last longer into this evening than usual, but
no other surprises expected in terms of direction. Onshore flow
remains.

Vicinity of SFO...As of this issuance, cigs expected to become
less problematic as weak front moves through and gradually lifts
cloud decks. However, IFR cigs may periodically linger through
about the 14Z hour. Otherwise VFR and gusty NW winds this
afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR/IFR cigs lingering this morning,
expected to mix out as a weak front moves through. However, strong
NW flow and better moisture moving in along the coast will likely
keep some degree of cloud cover around today. VFR expected
through the afternoon, but perhaps an early return of marine
stratus by the 02Z hour, moderate-high confidence.

&&

.MARINE...
(Today through Wednesday)
Issued at 418 AM PDT Fri Apr 11 2025

Winds gradually increase to a strong breeze across the waters this
afternoon, approaching near gale force tonight over the northern
outer waters and isolated areas south of Point Sur. Another
moderate period northwesterly swell 10 to 12 feet at 10 to 11
seconds arrives by Saturday morning.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Mry Bay.

     Small Craft Advisory until 3 PM PDT Saturday 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 Reyes to Pigeon Pt 0-10 nm.

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

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

     Gale Warning from 3 PM this afternoon to 9 AM PDT Saturday for
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Behringer
MARINE...Behringer

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