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000 
FXUS66 KMTR 132353
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
353 PM PST Wed Dec 13 2017

.SYNOPSIS...Persistent high pressure over the region will continue to 
result in well above average daytime temperatures and seasonably 
cool overnights through the weekend. Periods of breezy to locally 
gusty winds will remain possible along the ridges and peaks across 
the region. 

&&

.DISCUSSION...as of 01:38 PM PST Wednesday...A strong mid/upper 
level ridge of high pressure over the West Coast continues to 
produce mainly clear weather conditions and unseasonably warm 
daytime temperatures. Closer to the surface, a tight pressure 
gradient has resulted in breezy to locally gusty offshore winds 
along the ridges and peaks. These winds will again pick up a bit 
during the overnight hours with some of the highest peaks seeing 
winds gusting up to around 40 MPH. Along with this, very dry 
conditions continue with relative humidity values in the single 
digits. These winds are then forecast to diminish Thursday into 
Friday as the pressure gradient along the coast weakens. 
Meanwhile, light to variable winds in the valley locations will 
allow temperatures to cool into the 30s with lower 40s closer to 
the coast/bays. 

Daytime temperatures trend slightly lower this weekend as an upper 
level trough pushes into the Pacific Northwest and drops down along 
the West Coast. As the trough approaches northern California, 
forecast models project a deepening low pressure system to develop 
which will increase winds across the region. Thus, breezy to locally 
gusty winds are likely Friday night into Sunday. With that said, dry 
weather conditions are likely to persist with very limited 
atmospheric moisture associated with the passing system. Will need 
to keep an eye on the forecast wind speeds this weekend as the GFS 
and local WRF indicate wind gusts of greater than 50 MPH possible, 
especially in the North and East Bay Hills/Mountains. 

High pressure then builds back in over the region early next week. 
Heading into the middle part of next week, the forecast models 
diverge and continue to flip-flop on the potential for precipitation 
across our region. Will continue to monitor the latest models 
guidance in the coming days as forecast confidence remains very low 
at this time.

&&

.AVIATION...As of 3:45 PM PST Wednesday...Surface high pressure
over the Great Basin will continue to influence the area through
Thursday for VFR conditions. The exception is KSTS where fog will
likely develop again overnight. 

Vicinity of KSFO...VFR.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Southeast winds to 10 kt in the
Salinas Valley early Thursday morning.

&&

.CLIMATE...

HERE IS A LIST OF RECORD HIGH TEMPERATURES ALONG WITH THE MOST 
RECENT DATE IT OCCURRED.

SF BAY AREA                     December 13     December 14
.LOCATION................
 HEALDSBURG..............       76/1911         77/1942
 SANTA ROSA..............       74/1958         72/1956
 KENTFIELD...............       73/1911         70/1942
 SAN RAFAEL..............       69/1950         70/1959
 NAPA....................       72/1934         73/1959
 SAN FRANCISCO...........       71/1911         69/1988
 SFO AIRPORT.............       69/1958         69/1958
 OAKLAND AIRPORT.........       70/1958         65/1958
 RICHMOND................       75/1958         67/1983
 LIVERMORE...............       73/1958         75/1958
 MOFFETT FIELD...........       68/1953         72/1958
 SAN JOSE................       70/1958         73/1958
 GILROY..................       78/1958         72/1988

MONTEREY BAY AREA
.LOCATION................
 MONTEREY................       77/1953         78/1953
 SANTA CRUZ..............       77/1944         82/1953
 SALINAS.................       79/1958         80/1988
 SALINAS AIRPORT.........       80/1953         81/1953
 KING CITY...............       79/1936         83/1958

&&

.MARINE...as of 03:41 PM PST Wednesday...Northwest winds will
continue over the waters overnight as a northwest swell with a
period of 16 to 17 seconds arrives. Winds  will increase late
Friday and into the weekend as a cold front  passes through the
area.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...None.

$$

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

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