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Area Forecast Discussion (AFD)

Issued by San Francisco Bay Area, CA (MTR)

FXUS66 KMTR 221157

Area Forecast Discussion
National Weather Service San Francisco Bay Area
457 AM PDT Wed May 22 2019

.SYNOPSIS...Isolated to scattered showers will linger through the 
early morning before drier conditions develop this afternoon. 
Temperatures will be on the warming trend through the remainder of 
the week, yet will remain below seasonal averages. Unseasonably cool 
and unsettled conditions continue into the upcoming weekend with a 
renewed chance of rain showers as another system drops southward 
across the region. 

&& of 03:16 AM PDT Wednesday...Another active 
morning with isolated to scattered showers, especially over the 
Central Coast and coastal waters, as a short-wave disturbance 
associated with the mid/upper level trough digs southward across 
the region. Rainfall amounts during the past 6 hours or so range 
from a few hundredths to a tenth of an inch for most areas while 
some inland portions of the Bay Area have remained dry. Meanwhile,
locally heavier rainfall has been reported within heavier showers
with totals during the same period of around one- quarter to one-
half of an inch. While these showers are likely to taper off from
north to south through the early morning, we cannot rule out an 
isolated thunderstorm or two over the waters or along the Central 
Coast before completely diminishing. Also of note, profiler data 
at Point Sur indicates a snow level of around 5,200 feet with 
Chew's Ridge surface temperature hold around 33-34 deg F. Thus, 
cannot rule out the region's highest peaks seeing some snowfall 
early this morning. For the remainder of the day, conditions will 
dry out with temperatures warming about 4 to 8 degrees across the 
interior compared to yesterday. 

In wake of the departing mid/upper level low, broad troughing will 
persist over much of the western portion of the country through late 
week. Being on the west side of the trough, temperatures will warm 
slightly yet generally remain below seasonal averages with 60s at 
the coast to lower/middle 70s inland. May get enough daytime heating 
on Thursday for a few showers to develop over interior portions of 
the Central Coast based on short-range guidance. However, widespread 
rainfall is unlikely through the remainder of the workweek. 

Medium and longer range models indicate additional disturbances 
rotating through the western periphery of the through this upcoming 
weekend. Thus, look for increased chances of rain showers from late 
Saturday into Sunday. With this said, confidence in widespread 
rainfall occurring over the region remains low at this time. 
Something worth keeping an eye on in the coming days if you have 
outdoor plans this upcoming weekend. Regardless, cool and unsettled 
conditions are likely to persist heading into early next week given 
the unseasonably "troughy" pattern over the region. 

&& of 04:57 AM PDT Wednesday...Upper low is tracking 
to the southeast with showers decreasing in coverage from north to
south. A few showers will be possible at SJC MRY and SNS early 
this morning. Clearing is occurring in the wake of the low but 
residual low-level moisture is preventing skies from completely 
clearing. Most terminals are expected to experience prevailing VFR
conditions through the morning but occasional MVFR will likely 
occur through mid to late morning due to the residual moisture. 
Generally west-northwest winds this morning at 5-10 kt will 
increase this afternoon to 10-15 kt at most sites. Mainly VFR 
conditions expected through the evening hours, with MRY most 
likely to develop MVFR cigs by mid evening.

Vicinity of KSFO...VFR expected to prevail with SCT at 2000-3000
feet this morning but occasional MVFR cigs possible through late 
morning. Breezy west- northwest winds with gusts to 20 kt expected
to decrease early this morning and then increase once again early
this afternoon with gusts 20-25 kt possible.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Scattered showers near MRY possible
through 18z, with decreasing showers near SNS through mid
morning. A mix of MVFR/VFR expected this morning with clearing
late morning. A return to MVFR cigs expected around mid evening.
Northwesterly winds of 10-15 kt this afternoon. 

&& of 03:16 AM PDT Wednesday...A large northwest swell 
has arrived with seas in excess of 15 feet along with larger near 
shore breaking waves. Low pressure will move inland into the Great
Basin and the Central Valley on Wednesday. This will result in 
increasing northwest winds with gale force gusts expected over the
northern and outer waters. Gale force winds and large northwest 
swell will create hazardous conditions through midweek. Moderate 
wind and seas will persist through the end of the week, 
particularly in the northern outer waters.


     .Tday...High Surf Advisory...CAZ006-505-509-529-530
             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 Pt Reyes 0-10 nm until 11 AM
             SCA...Pt Arena to Pigeon Pt 10-60 nm until 11 AM
             GLW...Pt Arena to Pigeon Pt 10-60 nm from 11 AM
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 2 PM
             GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 2 PM
             GLW...Pt Arena to Pt Reyes 0-10 nm from 11 AM
             SCA...Rough Bar Advisory for SF Bar
             SCA...Mry Bay




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