Scientific Forecaster Discussion
fxus66 kmtr 221708
Area forecast discussion
National Weather Service San Francisco Bay area
908 am PST Fri Nov 22 2019
Synopsis...temperatures remain seasonable today with values
expected to be similar to yesterday. Winds will switch to light
and offshore keeping conditions dry over the Bay area. Stronger,
dry offshore flow is expected Monday before the switch midweek as
colder conditions with unsettled weather is expected to develop
over the region as early as Tuesday of next week and continue
through Thanksgiving, likely impacting Holiday travel.
Discussion...as of 08:59 am PST Friday...a very weak upper level
ridge builds over the Bay area and the central California coast
Friday. Temperatures will remain consistent with high temperatures
to remain in the 60s, similar to Thursday, and last through the
weekend. Overnight lows are expected in the upper 30s to mid 40s
allowing patchy frost in isolated locations to appear.
Winds will switch over to offshore ushering drier air over the
Bay area this weekend. Winds will reach their maximum on Monday
particularly in the North Bay hills and East Bay hills. It will be
monitored closely as fire weather concerns remain elevated as
fuels remain dry, but due to model inconsistency confidence
By late Tuesday, the pattern changes as a short wave trough moves
through the Bay area and central coast. Models have been
consistent in bringing widespread rain midweek and through the
Thanksgiving Holiday. Rain could potentially be heavy,
particularly late on Tuesday as a cold front moves through the
region. Temperatures are forecast to drop where high temperatures
only reach the 50s in most areas, with colder values in elevated
Aviation...as of 5:20 am PST Friday...light easterly wind over
the Bay area from the low pressure system over the southwest.
Winds will switch to a light onshore this afternoon as the
influence of the low diminishes. Low clouds along the coast
skirting the peninsula and the mry Bay area and the Salinas valley
this morning. Models indicate less low level moisture tonight and
Saturday morning even though the flow is onshore so VFR expected
Vicinity of ksfo...sct-bkn clouds through 17z with bases around
2000 ft. Light easterly wind this morning becoming onshore to 10
kt late in the day.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...clouds in the Salinas valley are lower
than the coastal clouds. MVFR at mry but IFR at sns with vsbys
down to 3-5 miles. Clearing after 16z.
Marine...as of 08:59 am PST Friday...Friday will see low pressure
slowly move east and higher pressure will grow on Saturday.
Easterly winds will switch to north to northwest tonight. A long-
period northwest swell will arrive today and continue through the
weekend. Winds will increase late Sunday or Monday as a strong
... Arena to Pigeon pt 10-60 nm from 9 am
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm from 3 PM
Public forecast: dk
aviation: west pi
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