Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
856 PM PST Monday Feb 8 2016
Synopsis...temperatures will gradually trend cooler through the
the rest of the week. Outside of a slight chance for rain over
the far North Bay Friday and Friday night, dry weather is
Discussion...as of 8:56 PM PST Monday...no updates this evening.
It was a record breaking day with 12 climate sites tying or
breaking record highs. The offshore gradient is still nearly 14
mb from the Great Basin to sfo and 8 PM temperatures still in the 60s.
Satellite shows skies are clear and expect that to continue
After todays record breaking heat...expect temperatures to cool several
degrees on Tuesday as winds turn westerly by afternoon. However
readings will still be well above normal with lots of 60s and 70s
across the district.
Gradual cooling through the week back to normal with a weak
trough passing to our north around Friday. In general the pattern
is uneventful. Gem/European model (ecmwf) and GFS hinting at next rain chance by
later next week...around Feb 18-19th.
Previous discussion...as of 3:00 PM PST Monday... an unseasonably strong
588dm ridge continues to dominate the regional weather pattern
today. Climatological anomalies for near surface temperature
fields are 3 to 4 Standard deviations above the normal... which
typically coincides with record high values. Temperatures in the
70s to low 80s are coming in across the region... with some of the
warmest temperatures along the coast in places like Big Sur
(86)... the Sonoma coast(80 at sea ranch)... and the Monterey
peninsula (85 at pebble beach). Official records continue to fall
across the region today... with official records broken at Oakland
Airport (79 vs 70)... Oakland museum (78 vs 77)... San Jose (76 vs
75)... Monterey (83 vs 81)... and tied at San Francisco downtown
(74) as of 2pm with potentially more records to come by the end of
the day. Temperatures at the surface are being enhanced further by
the relatively strong offshore winds experienced across the region
today. These winds compress and thus warm the atmosphere as they
descend to the surface. For example... Oakland Airport shot up to
79f from 68f in less than an hour when the wind direction backed
from the south to the northeast... indicating the arrival of warm
downsloping offshore winds. These offshore winds had previously
extended all the way to the coast... as is evident by the
extremely warm temperatures previously noted there... however the
thermal trough has now shifted just inland leading to the arrival
of a weak afternoon sea breeze along the immediate coast.
The ridge of high pressure will sluggishly shift eastward tomorrow
but continue to dominate the local weather. Temperatures will cool
slightly into tomorrow but remain up to 10 degrees above average.
Warming offshore winds will continue into tomorrow but be slightly
weaker than todays winds.
The upper ridge shifts over the intermountain west through the
remainder of the week... leading to gradually cooler temperatures
and continued dry weather for a majority of the forecast area.
Temperatures will approach normal seasonal values by the end of
the week. That said... forecast models hint at a slight chance of
rain for the extreme North Bay on Friday as a weak trough
approaches the Pacific northwest.
Aviation...as of 7:20 PM PST Monday...surface high will continue
over the Great Basin through Tuesday. Offshore flow has weakened
so winds will be light. This may allow some stratus and fog to
form around ksts early Tuesday morning.
Vicinity of ksfo...VFR with light east to southeast winds.
Sfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR.
Beaches...as of 7:20 PM PST Friday...swell periods increased to
17 to 19 seconds this morning with swell heights in the 6 to 8
foot range. Swell periods now in the 15 to 17 second interval and
will continuie to become shorter through tonight and Tuesday. The
beach hazard statement will be allowed to expire at 8 PM.
Climate...record highs for Monday...
City name Feb 8th high and year
Kentfield 71 in 2006
San Rafael 72 in 1980
Napa 73 in 1987
San Francisco 74 in 2006
sfo Airport 73 in 2006
Oakland museum 77 in 2006
Oakland Airport 70 in 2006
Richmond 78 in 2011
Livermore 78 in 1917
San Jose 75 in 1987
Gilroy 78 in 1963
Monterey 81 in 1954
Santa Cruz 78 in 1954
Salinas 83 in 2006
Salinas Airport 83 in 1954
King City 84 in 2006
Marine...as of 08:43 PM PST Monday...a strong area of high
pressure over the Great Basin will maintain light southeast winds
across the coastal waters. Offshore winds will be gusty in the
vicinity of the coastal mountain gaps. Onshore flow will return
Tuesday as the high weakens.
Public forecast: r_walbrun/drp
aviation: west pi
marine: west pi
Visit US at www.Weather.Gov/sanfrancisco
Follow US on facebook and twitter at: