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Area forecast discussion 
National Weather Service San Francisco Bay area
418 am PDT Tuesday Jul 28 2015

..very warm to hot inland temperatures expected today through
Thursday of this week....

Synopsis...a significant warm-up is forecast to continue across
inland areas through midweek...and more modest temperature
increases closer to the coast as strong high pressure builds over
the region. Temperatures cool slightly late in the week along
with increased monsoon moisture approaching from the south.

&&

Discussion...as of 3:15 am PDT Tuesday...completely clear start
to the day today will both satellite and surface observation indicating no
cloud cover across our County Warning Area or over the waters. Current surface
analysis shows north to south gradient at 4 mb or double of west
to east. That combined with a marine layer squashed to around 500
feet has lead to the clear start.

Bigger picture synoptically shows a building ridge of high
pressure to our south that will advance through our County Warning Area later
today. At the same time 850 mb temperatures will rise around 3c by this
afternoon compared to yesterday. This will help to push highs to
above normal levels for almost all locations. Inland highs will
generally be in 90s to lower 100s while coastal spots will see
less of a warm up due to afternoon sea breezes. Highs close to the
coast will generally be in the upper 60s to around 80s.

The ridge will remain the dominate weather feature through
Thursday as 850 mb temperatures increase an additional 2 to 3c and 500 mb
heights increase another 2 to 3 dm. This will lead to two
additional days of very warm temperatures inland with highs again
expected to generally be in the 90s to lower 100s. Models continue
to favor onshore flow for both afternoons which will help to
moderate the heating.

Worth noting that guidance this morning compared to the previous
two mornings has slightly backed off on the heating for the week
suggesting that a heat advisory is not necessary.
Regardless...temperatures will still be quite warm.

By late Thursday subtropical moisture rotating around the ridge
of high pressure will advance toward our region. Whether or not
enough of it makes it to our County Warning Area along with significant
instability remains to be seen. 0z GFS brings scattered showers
and thunderstorms to the southern quarter of the County Warning Area for late
Thursday through Friday night while the GFS and navgem keep any
shower activity to the south and east. NAM solution brings a few
showers to San Benito County on Friday. Went with a slight chance
for showers and thunderstorms until better agreement can be
reached.

Longer rang outlook for the weekend through next week keeps shower
activity to our east along with highs near to slightly above
normal.
&&

Aviation...as of 4:17 am PDT Tuesday...VFR conditions through the
period. High confidence.

Vicinity of ksfo...VFR conditions will prevail through the forecast
period. Light winds

Ksfo bridge approach...similar to ksfo.

Monterey Bay area terminals...VFR conditions will prevail through
the forecast period. Light winds.

&&

Climate...here are record highs for Tuesday through Thursday
across our area along with the last year the record was recorded.

Sf Bay area..............7/28............7/29............7/30
Kentfield..............98/1934........105/1954........105/1977
San Rafael............104/1980........101/1977........102/1977
Napa..................107/1954........105/1954........103/1977
San Francisco..........84/1954.........83/1977.........85/1986
sfo....................88/1954.........91/1977.........97/1977
Oakland................76/1977.........98/1977.........95/1977
Oakland Airport........96/1954.........91/1977.........95/1977
Richmond...............88/1954.........82/1967.........80/1993
Livermore.............106/1980........108/1954........107/1979
Mountain View..........93/1954.........93/1977.........97/1977
San Jose..............100/1954.........95/1977........102/1995
Gilroy................101/1995........102/1980........106/1977

Monterey Bay area........7/28...........7/29.............7/30
Monterey...............85/1954........86/1977..........91/1977
Santa Cruz.............92/1947........88/1964.........102/1977
Salinas................92/1954........95/1977..........86/1995
Salinas Airport........84/1967........92/1977..........84/1977
King City..............99/1967.......105/1977.........106/1977

&&

Marine...as of 04:16 am PDT Tuesday...locally gusty northerly
winds will be possible again today as high pressure remains over
the Pacific northwest and low pressure inland. The strongest winds
will be north of Point Reyes. The gusty winds will gradually
decrease this afternoon as the pressure gradient weakens with
improving sea conditions.

&&

Mtr watches/warnings/advisories...
... Arena to Pigeon pt 10-60 nm until 3 PM
Small Craft Advisory...sf Bay from noon

&&

$$

Public forecast: Bell
aviation: mm
marine: mm
climate: Bell/Benjamin



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