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Area Forecast Discussion (AFD)

Issued by San Francisco Bay Area, CA (MTR)

                            
000
FXUS66 KMTR 162138
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
138 PM PST Sat Feb 16 2019

.SYNOPSIS...Cool weather conditions will persist along with 
continued shower activity through Sunday afternoon. Accumulating 
snow is likely above 3,000 feet, with snow levels lowering to 
around 2000 by Sunday morning. Overnight temperatures turn colder 
early in the upcoming work week as precipitation ends and sky 
conditions clear. A chance of showers will return by the middle of
next week, with below normal temperatures expected through the 
period.

&&

.DISCUSSION...as of 01:37 PM PST Saturday...Isolated to scattered
showers continue to spread over the region this afternoon with 
only isolated reports of small hail. With snow levels estimated at
around 2,800 feet across the North Bay, do expect snow showers 
are occuring over that region's highest elevations along with the 
higher peaks down along the Central Coast. Expecting this pattern 
to continue through the evening with another round of more 
widespread showers to develop late in the night and into early 
Sunday morning as the next mid/upper level system descends 
southward along the northern California coast. The latest short- 
range models all show an uptick in showers over the region as snow
levels begin to drop to around 2,000 feet in the North Bay and 
3,000 feet in the southern portion of the region by Sunday 
morning. Given the best chance for accumulating snow to occur in 
elevations at or above 3,000 feet, will hold off on a Winter 
Weather Advisory as impacts will generally be limited. Additional 
rainfall amounts will range from a few tenths of an inch to around
one-half inch in most urban areas with amounts locally upwards of
one inch in the hills/coastal ranges. With that said, the highest
peaks (above 4,000 feet or so) in the region could see a good 6 
to 12 inches of snowfall by tomorrow afternoon. Showers are 
forecast to diminish from north to south Sunday afternoon and 
evening with dry conditions developing region-wide Sunday night. 

As precipitation comes to an end, sky conditions will begin to clear 
and allow for colder overnight/morning temperatures early in the 
week. Look for upper 30s to lower 40s near the coast with lower to 
middle 30s across inland areas. Higher elevations, especially where 
snowfall is greatest will cool into the upper 20s. With a cold 
mid/upper level trough still in place over the western portion of 
the country, daytime temperatures will only warm into the 50s for 
most coastal and valley locations while 30s and 40s will be common 
in the higher terrain.

The forecast models continue to suggest another mid/upper level 
disturbance dropping down the West Coast on Wednesday which will 
bring renewed chances for rain/snow showers to the region. 
Confidence in the details remain low at this time given model-to-
model and run-to-run inconsistencies. Regardless, precipitation 
amounts would likely be minimal and not result in widespread 
flooding impacts. The aforementioned cooler air mass would remain in 
place and could result in higher elevation snowfall once again as 
rain showers would be most likely in the urban areas. Seasonably 
cool conditions are also forecast to persist with conditions drying 
out Friday into next Saturday.


&&

.AVIATION...As of 9:50 AM PST Saturday...Scattered showers 
continue to roll through the area. Hi-res models indicate an 
increase in shower activity by late afternoon and again early 
Sunday morning as a couple of upper level disturbances move 
through. Cigs remaining VFR at 4000 ft or above. 

Vicinity of KSFO...VFR with cigs remaining at or above 4000 ft. 
On and off showers through Sunday morning. Westerly winds gusting
as high as 20-25 kt from 20Z through 04Z. 

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR with scattered showers coming off the
bay through Sunday morning. 

&&

.BEACHES...As of 9:50 AM PST Saturday...Latest buoy reports at 9 
AM indicated 13 to 16 foot swells with 16 second periods. A high 
surf advisory is in effect through 9 PM Saturday for breakers as 
high as 18 to 25 feet along west and northwest facing beaches. 
Swells will slowly subside tonight. 

&&

.MARINE...as of 09:38 AM PST Saturday...High pressure centered
1150 miles west of Cape mendocino combined with low pressure over
the Pacific Northwest are producing moderate northwest winds along
with large northwest swells over  the coastal waters. Winds will
continue through early next week as the low slides into the Great
Basin. Swells will start to decrease tonight and Sunday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...High Surf Advisory...CAZ006-505-509-529-530
             SCA...SF Bay
             SCA...Mry Bay
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Rough Bar Advisory for SF Bar until 3 AM

&&

$$

PUBLIC FORECAST: RGass
AVIATION: W Pi
MARINE: W Pi

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