943 
FXUS66 KMTR 061017
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
217 AM PST Sun Nov 6 2022

.SYNOPSIS...Active weather continues through midweek with multiple
disturbances moving through the area, bringing rain beginning late
tonight with periods of heavier rainfall possible on Monday. 
Temperatures will remain below seasonal averages and feel down 
right blustery at times early in the week followed by cold 
overnight temperatures late week. 

&&

.DISCUSSION...as of 02:14 AM PST Sunday... 

Rest of tonight through this afternoon... Happy "Fall Back" 
Sunday and end of daylight saving time for now.

KMUX radar showing some weak echoes as a weak cold front moves 
through the Central Coast, squeezing out some drizzle and light 
rain. Tonight, rain gauges scattered throughout the Bay Area 
picked up a few hundredths of an inch as a result. Surface obs 
also show temperatures and dew points higher compared to 24 hours 
ago in the warm sector, but will drop off as the boundary
continues to move through. Shower activity will diminish late this
morning and afternoon before the main batch of rain arrives later
this evening. Another fall-like day today with highs in the 60s 
across the area and cloudy skies. 

This evening through early Wednesday.. 

Active weather pattern continues as a deep low pressure system is
on track to dip down from the Pacific NW late tonight into
tomorrow morning. This system will bring more impressive rain 
amounts to California. As mentioned in previous discussions, this
next round of rain is accompanied by a more organized weather system
with a more robust frontal boundary and a strong mid/upper level 
jet, leading to better conditions for heavier rainfall due to 
enhanced upward motion. 

The main line of rain associated with the FROPA will arrive after
9 PM tonight in the North Bay, then moving south through 
SF/Oakland down into San Jose after midnight. Behind the cold 
front, rain chances are not over with thunderstorms possible on 
Monday. Cooler temperatures aloft in the post frontal environment 
as well as ample moisture supply will lead to weak to moderate 
instability (MUCAPE values Monday afternoon range from 100 to 300
J/kg). The Storm Prediction Center includes NorCal/Central Coast 
in their mention of general thunderstorms on Sunday and Monday. As
such, localized heavier rainfall rates are possible as well as 
the potential for small hail and some rumbles of thunder. Periods 
of heaviest rain will likely occur Monday evening into Tuesday 
morning. This rain could lead to nuisance flooding on roadways, so
be sure to use caution if driving. 

Forecasted rainfall totals for this system (now through Wednesday
morning) is looking to be slightly higher than previously 
advertised, but roughly still about an inch across the region 
(rainshadowed regions receiving slightly less than an inch, but 
high confidence of more than a half inch). Higher elevations such 
as the Santa Cruz Mtns and the Santa Lucias/Big Sur could see 
2-2.5 inches (up to 3"). Stay tuned as we continue to fine tune
the QPF forecast as the system gets closer.

In addition to rain and potential thunderstorms, strong wind 
gusts likely along ridgetops/higher elevations and near the 
coastline. Most recent MTR WRF run has upped the winds near time 
of frontal passage (late Sunday/early Monday), indicating winds
could be gusty and erratic. Also seeing that surf conditions will
become increasingly hazardous as building surf will ensue Sunday 
evening into Monday, so if planning to go to the beach, use
caution and never turn your back to the ocean!

Wednesday and beyond...

The mid/upper level low remains over the West Coast until late
Wednesday before moving eastward into the Intermountain West. On 
the back side of the system, cold air advection will result in chilly
overnight temperatures will return midweek. Temperatures in the 
low 30s (at or near freezing) will be possible for interior 
valleys both Thursday and Friday mornings.


&&

.AVIATION...as of 11:08 PM PDT Saturday...For the 06Z TAFs. Areas of 
MVFR and IFR CIGs last into the late night, but VFR begins to return 
early Sunday morning with the exception of some patchy fog and low 
clouds in the North Bay. Sunday afternoon offers moderate winds and 
building mid to high clouds ahead of the next frontal boundary. The 
oncoming front looks to offer breezy winds MVFR CIGs and showers 
into Sunday evening with chances lasting into the night. Rain 
chances enter the region from the nor

Vicinity of KSFO...MVFR through the early morning, followed by VFR 
as CIGs lift. Winds stay lighter through the night but build into 
Sunday afternoon. Breezy and gusty winds build into the late 
evening, Sunday, as showers begin to move into the SF Bay. These 
rain chances could cause some reduction in visibility and are 
expected to last into late Sunday night. 

KSFO Bridge Approach...Similar to SFO.

Monterey Bay...Light rain and drizzle lingers into the late night 
with MVFR/IFR CIGs expected through the late morning with light 
winds. CIGs lift and VFR returns in the late morning with moderate 
winds. The front begins to approach the Monterey Bay into Sunday 
night, bringing variable winds and rain chances into the late
night.&&

.MARINE...as of 11:08 PM PDT Saturday...Gentle to moderate
northwest winds will gradually weaken into Sunday morning. Winds
shift to the south-southwest on Sunday as a cold front approaches
from the north. Fresh to strong breezes will develop along and
behind the front, as winds veer to the northwest late Sunday.
Moderate northwest swell persists throughout the  weekend, before
a much larger swell arrives early on Monday,  which, combined with
the breezy winds, will result in hazardous  seas with wave heights
reaching 14 to 16 feet. An unstable airmass settles in Monday as
well, which will bring chances for thunderstorms throughout the
waters. Winds and seas will continue to be elevated and hazardous
through midweek.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...SCA...Pt Arena to Pigeon Pt 10-60 nm

&&

$$

PUBLIC FORECAST: McCorkle/Murdock
AVIATION: Murdock 
MARINE:Lorber

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea