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

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FXUS66 KMTR 242331

Area Forecast Discussion
National Weather Service San Francisco Bay Area
431 PM PDT Tue Apr 24 2018

.SYNOPSIS...A cooling trend is forecast to persist through late
week and into the upcoming weekend as an upper level trough
approaches from the Pacific. This system may produce a few showers
over the North Bay late Friday into Saturday as it pushes inland
north of our region, yet widespread rainfall is unlikely.

&& of 01:48 PM PDT Tuesday...The mid/upper level
ridge axis continues to shift further inland away from the West
Coast today in advance of a broad trough well offshore. This has
allowed for cooling region-wide today (currently 16 deg F cooler
at Santa Rosa compared to 24 hours ago) with a marine layer
between 1,200-1,500 feet in depth. With this, onshore flow persist
along with coastal stratus.

The upper level trough and an associated low pressure system will
slowly approach the California coast through late week. As a result,
look for continued cooling, even inland, with coastal stratus
penetrating inland each night before retreating back to the coast
during the mid/late morning hours. Daytime temperatures will
generally range from the upper 50s to middle 60s at the coast to
middle/upper 70s inland through Thursday.

The center of the upper level low is then forecast to push into
northern California Friday into Saturday and bring a slight chance
of rain showers to the far northern portion of the North Bay.
However, not expecting much in the way of widespread rainfall as the
core of this system stays well to our north. Elsewhere, temperatures
cool to below seasonal averages with ongoing dry weather conditions
likely into the upcoming weekend.


.AVIATION...As of 04:31 PM PDT Tuesday...For 00z tafs. Currently
VFR with stratus along the Central Coast and passing high clouds.
Expecting stratus to intrude once again tonight into tomorrow
morning bringing IFR/MVFR cigs to all terminals. Gusty onshore
winds will continue into this evening before winds subside and low
clouds move in.

Vicinity of KSFO...VFR with breezy onshore winds through this
evening. MVFR cigs to return at around 10z.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR through early this evening with
onshore winds around 10-15 kt. Stratus and fog to return this
evening with IFR conditions expected at around 03z.

&& of 02:15 PM PDT Tuesday...Generally light onshore
winds will persist through the week, with locally breezy to gusty
winds near coastal gaps or prominent  points such as the Golden
Gate bridge and Point Sur. Light to  moderate seas will prevail
through the forecast period with a  mixed southerly and
northwesterly swell developing late this week.





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