Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 121731

Area Forecast Discussion
National Weather Service San Diego CA
931 AM PST Tue Dec 12 2017

High pressure aloft and weak offshore flow at the surface will
continue warm dry weather into next week. Brisk offshore winds
will occur mainly in the foothills during most nights and
mornings. Skies will be mostly clear.




The morning San Diego sounding continued to show an extremely dry
airmass in place with PW only registering 0.15 inches. Offshore
flow continues this morning, but rather weak. A few foothill
locales had wind gusts 30-40 mph, but winds were light/calm across
most of the area. Another day of above normal temps will be felt.
No changes were made to the forecast this morning. See previous
discussion below for further forecast details.

...Previous Discussion (Issued at 208 AM PST Tue Dec 12 2017)...

We`re forecasting very persistent weather from day to day this
coming week. Barely perceptible is a subtle drop this morning in
humidity across most areas. Winds are about the same as on Monday
morning, with a few foothill areas gusting over 30 mph. This
picture will appear much the same on Wednesday. On Thursday a
coastal eddy will increase the humidity near the coast, but low
clouds and fog are not likely. In fact, we only expect a few high
clouds from time to time. Tis the season for dry offshore flow,
interspersed with winter storms. We`re just not getting the winter
storm part. High pressure aloft will persist over Alta California
along with a stationary upper low over Baja California. The
resulting easterly flow over Southern California will provide
most nights and mornings with areas of brisk offshore winds in the
foothills. High temperatures will be 5 to 15 degrees higher than
average, meaning a lot of 70s and 80s at lower elevations. A
shortwave trough scoots through the interior West Friday night and
Saturday, forcing a touch of onshore flow that will bring us our
coolest day in the coming week with upper 60s and 70s. That will
be immediately followed by a boost in offshore flow and warmer
weather Sunday into Monday. The storm door has been closed and
locked, thanks to a persistent high amplitude ridge of high
pressure along the West Coast. There are some signs that maybe
enough lows or troughs will knock or even bang on the western
ridge enough to finally break through the door and allow storms to
come in. Both the GFS and Euro models show a general long wave
switch: the western ridge for the eastern trough. That is
indicated ten days out around 21 or 22 December, which is in
weather fantasy land.


121700Z...Mostly clear with unrestricted vis through Wednesday


No hazardous marine weather is expected through Saturday.


Very dry weather will continue this coming week, with brisk
offshore winds mainly in the foothills through Wednesday. Slightly
higher humidity is expected Thursday through Saturday and winds
will be light. Offshore flow redevelops Sunday into Monday for
dry weather again along with brisk offshore winds mainly in the
foothills. A higher than average fire danger will persist as fuels
and air remain very dry, but critical fire weather conditions are
not expected.


Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.




PUBLIC...Gregoria (Update)/Prev Discussion (MM)
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