Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 110531
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
930 PM PST Sun Dec 10 2017

.SYNOPSIS...
A Santa Ana weather pattern will bring warm days and cool nights
this week. Weak to locally moderate offshore winds will continue,
mainly in the mountains and foothills.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

John Wayne Airport in Santa Ana was the warmest in the nation today
with a high of 88. Record highs were set at Newport Beach (85),
Vista (85) and El Cajon (83). Warm and dry weather will continue
through Friday with temperatures 10-20 degrees above average in the
coastal, valley and mountain zones, and 5-10 degrees above
average in the deserts.

The Santa Ana winds were still fairly strong in the mountains and
foothills this evening, but not as strong as they were last night.
At 9 PM, winds were gusting to 45 mph at Sill Hill and 40 mph at
Alpine. These gusty winds will continue at times through Tuesday as
a 1040 mb surface high remain anchored over Utah. On Wednesday the
surface high finally weakens to 1030 mb, and the winds will be
noticeably lighter in the mountains and passes.

The 00Z NKX sounding was very dry from the surface to 25kft feet
with the RH below 15% through the column. From 25-40kft the humidity
was >70%, as high level moisture and cirrus clouds drifted up from
the closed low west of central Baja. The high clouds and local east
winds will bring another mild night to windy areas where lows will
be in the 50s to low 60s. It will still be cool in the wind
sheltered areas with lows in the 40s.

*From Previous Discussion*

Overall, with the West Coast ridge combined with the eastern North
American trough and surface high pressure over the Great Basin, we
will continue to have above normal temps, mostly 75-85 for highs,
through Wed or Thu, then decreasing slightly due to some shortwaves
moving through the West Coast. Winds might increase slightly Tuesday
with a weak upper low to our south, but later in the week, the winds
will be relatively weak. Humidity will remain quite low, except
during sea breezes near the immediate coast, and no marine layer
will be present over the coastal waters. While the upper ridge looks
weaker from next weekend into early next week, there is no
indication of any system producing precipitation here for at least
10 days, probably longer.

&&

.AVIATION...
110500Z...NE to E winds 15-25 kt with gusts to 35 kt in the wind
prone passes and canyons and on the coastal mountain slopes and
foothills will create MDT UDDFS/LLWS over and W or SW of the
mountains through Monday. Otherwise, BKN clouds AOA FL200 and
unrestricted vis through Monday.

&&

.MARINE...
No hazardous marine weather is expected through Thursday.

&&

.FIRE WEATHER...
Very low humidity will continue this week, with inland areas having
5 to 10 percent minimums each day and poor nocturnal recoveries.
Humidity at the coast will be somewhat more variable due to
occasional sea breezes. Santa Ana winds will be moderately strong in
the wind prone areas with sustained winds 15-25 MPH with gusts to
near 45 MPH Monday and Tuesday. Winds will be lighter Wednesday
through Friday but the humidity will remain low. The fire weather
hazard will be elevated all week.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE

PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...Moede
AVIATION/MARINE...JMB


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