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Area Forecast Discussion (AFD)

Issued by San Francisco Bay Area, CA (MTR)

                            
000
FXUS66 KMTR 232359
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
459 PM PDT Sun Jun 23 2019

.SYNOPSIS...A cooling trend will slowly take hold of the region 
beginning Monday and remain for the better part of the week. Look
for more morning low clouds and cooler temperatures as a result. A
little coastal drizzle is possible with this pattern by midweek.

&&

.DISCUSSION...as of 02:11 PM PDT Sunday...Coastal fog is finally 
eroding along portions of the Bay Area coast. Although most of 
Monterey, Santa Cruz, and SF coasts continue to have haze or low 
clouds. The remainder of the Bay Area continues to be warm today, 
having reached the 80s and low 90s already. There will likely be 
another degree or two added to these reading, but should cap soon.

Synoptically speaking high pressure over the region will slowly
shift to the east over the next 24 to 48 hours as an upper level
trough moves into the Pacific Northwest and digs toward
California. This will bring a two fold change. One, it will deepen
the marine layer over the coming days. Therefore look for low
clouds instead of at the surface fog. By the time we get to
Wednesday into Thursday, the low clouds could make a significant
push inland. The marine layer could reach into the 3000 foot level
by mid to late week. Two, the onshore push and maritime airmass,
out of the Northwest, will bring a cooling trend to the region.
While the cool down will be nearly undetectable to people on 
Monday, by Tuesday it should be noticeable. By mid to late week, 
it looks like we could be 5 to 15 degrees below normal, depending 
upon location.

Looking longer term, models are showing a saggy trough hanging
around through next weekend. Temps may rebound a hair after the
midweek cool down, but should remain below normal through next
weekend. Looks like a weak ridge may have a shot at building by
the early part of next week as we head into July.

All in all, nothing to write home about for the next 5-7 days.
Typical Bay Area summertime weather with standard fluctuations 
around what is known as "normal".

&&

.AVIATION...as of 05:00 PM PDT Sunday...For 00z TAFs. A shallow
marine layer with a depth of around 1000 feet exists this 
afternoon mainly along the coast south of Pigeon Point. VFR 
conditions will continue through the evening at the TAF sites. Low
clouds and patchy fog will return to the Monterey Bay terminals 
late this evening and overnight. Breezy onshore winds will turn 
light and variable overnight. High pressure over the area will 
weaken and the northerly gradient will decrease slightly 
overnight which may result in a slight increase in the marine 
layer depth tonight. As such some of the terminals around SF Bay 
and the North Bay should see more widespread low clouds developing
towards sunrise.

Vicinity of KSFO...VFR. West-northwest winds 15-20 kt early this 
evening decreasing to 10 kt or less overnight. Patchy stratus may
develop near the terminal around 12-17z Monday but at this time 
SCT remains more likely than BKN or OVC. 

SFO Bridge Approach...VFR through the evening. An MVFR cig with
bases near 1000 feet may develop between 12-17z over portions of
the approach. 

Monterey Bay Terminals...VFR expected through late evening.
IFR cigs will develop overnight with periods of LIFR as well as
reduced visibilities likely. Cigs will clear to VFR Monday
afternoon. 

&&

.MARINE...as of 01:28 PM PDT Sunday...High pressure over the
eastern Pacific and a trough over inland California will maintain
gusty northwesterly winds over the northern outer waters through
Monday. Expect generally light to  moderate winds elsewhere. Winds
will diminish across the waters  Tuesday as high pressure weakens
and low pressure sets up off the  Pacific Northwest.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pt Arena to Pt Reyes 0-10 nm

&&

$$

PUBLIC FORECAST: BFG
AVIATION: ST
MARINE: RGass

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