Scientific Forecaster Discussion
fxus66 kmtr 211113
Area forecast discussion
National Weather Service San Francisco Bay area
413 am PDT sun Jul 21 2019
Synopsis...a warming trend is expected through the middle of next
week as an area of high pressure over The Four Corners region builds
westward. The most notable warming will occur inland, while
onshore flow will maintain mild temperatures near the coast. Inland
areas are likely to warm to above seasonal averages by midweek and
are persist into next weekend.
Discussion...as of 03:33 am PDT Sunday...a marine layer of
around 2,000 feet in depth has allowed for stratus to spread well
inland into the region's valleys this morning. With this,
temperatures are holding in the 50s to lower 60s for much of the
region with generally light onshore flow. Look for low clouds to
dissipate inland and retreat to the coast after sunrise with
mostly sunny conditions likely by the afternoon.
Inland temperatures will be noticeably warmer by this afternoon as
high pressure over The Four Corners builds westward. A warming trend
is then likely to persist through the first half of the week as the
ridge to our east strengthens and expands across California. This
too will help to compress the marine layer through early next week
and result in less widespread cloud cover for inland areas. However,
temperatures will remain near seasonal averages near the coast with
periods of night and morning low clouds. By Wednesday, inland areas
are likely to warm to about 5 degrees above average with widespread
80s and 90s. A few of the region's warmest locations may even reach
100 deg f late in the week. Meanwhile, daytime temperatures in the
middle 60s to middle 70s will be more common near the coast through
the upcoming week.
The ridge of high pressure over the southwestern portion of the
country is forecast to remain the dominate weather feature through
the extended forecast. Thus, dry weather conditions along with
temperatures near to slightly above seasonal averages will likely
Aviation...as of 4:13 am PDT Sunday...observations indicate
mainly light onshore winds except over at Travis AFB the wind is
gusting to 27 knots. Stratus clouds continue to spread inland this
morning resulting in a mix of LIFR-IFR ceilings and MVFR
ceilings. Far inland it's VFR. Patchy cirrus clouds with mainly
weak divergence in the subtropical jet stream will move up from
the south through today. Stratus should clear back to the ocean
from late morning to early afternoon then move back inland tonight
and Monday morning.
Vicinity of ksfo...MVFR ceiling until 17z, VFR for the remainder
of the day. Gusty onshore wind this afternoon to 20 to 25 knots.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...LIFR-IFR this morning, ceilings lifting
to VFR by late morning or early afternoon. LIFR-IFR returning
tonight and Monday morning.
Marine...as of 3:33 am PDT Sunday...high pressure over the
eastern Pacific will build into the Pacific northwest and far
northern California by mid to late week keeping gusty northwest
winds going over the northern coastal waters through this week.
Gusty onshore winds will develop each afternoon and evening this
week from the San Francisco Bay to the Delta.
... Arena to Pigeon pt 10-60 nm
Small Craft Advisory...sf Bay from 1 PM
Public forecast: rgass
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