Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS66 KMTR 110553

Area Forecast Discussion
National Weather Service San Francisco Bay Area
953 PM PST Sun Dec 10 2017

.SYNOPSIS...High pressure will remain over the west through most
of next week resulting in continued dry conditions. Daytime highs
will be warmer than normal and nights will be seasonably cool.


.DISCUSSION...As of 9:00 PM PST Sunday...Upper level high is over
northern Nevada this evening. Strong 1045 mb surface high
pressure over the Great Basin continues to dominate bringing dry
offshore flow to the area. This brought record high temperatures
around the South Bay and coastal areas today with records set at
San Jose...Salinas...and Half Moon Bay and tied at Monterey.
Nights will continue to be cool especially in the valleys where
patchy fog may form in wind-protected areas.

The upper high will get pushed slightly southeast as a weak upper
level shortwave approaches the British Columbia coast but will
keep its hold over our district through much of the coming week.
The surface high will slowly weaken over the next couple of days
but pressure gradients will still be offshore until Tuesday when
pressures between the coastal waters and inland areas equalize. By
then we should start to get a light seabreeze going. Daytime
temperatures are not going to change much this week with the
upper high still around. But nighttime temperatures will start to
moderate and there should be a little more humidity after

Medium range models are indicating the ridge will flatten late in
the week as a weather system moves into the Pacific Northwest but
rain will remain well north of the district. In fact by next
weekend high pressure rebuilds off the coast and surface high
pressure builds into Oregon bringing another round of offshore

Beyond that the 12z run of the ECMWF seems to be coming into
better agreement with the GFS in showing the ridge amplifying over
Alaska by the 20th and a trough moving in to take its place over
the West Coast with maybe even some precipitation for northern


.AVIATION...As of 9:49 PM PST Sunday for 06Z TAFs. Strong high
pressure will dominate the Bay Area through the forecast period,
resulting in VFR conditions and light winds. Went ahead and
removed fog from KSTS TAF. Forecast models are in fair agreement
that the boundary layer will be too dry to support fog from
forming tonight, but will still need to be monitored through the
night, just in case. Generally light offshore winds expected
overnight across the district.

High Confidence.

Vicinity of KSFO...VFR. Light offshore winds expected through the
forecast period.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Generally light offshore winds
overnight, with occasional moderate east/southeast winds through
the morning Monday, especially through the Salinas Valley.

&& of 9:31 PM PST Sunday...A strong stationary high
pressure ridge over the West Coast will keep winds over the bays
and ocean relatively light through the first half of the upcoming
week. A longer period west to northwest swell will arrive
overnight tonight and will continue through the day on Monday.





Visit us at

Follow us on Facebook, Twitter, and YouTube at: is the U.S. government's official web portal to all federal, state and local government web resources and services.