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Area forecast discussion 
National Weather Service San Diego California
349 am PST Sat Dec 27 2014

Synopsis...
chilly weather will continue through the rest of the weekend with
areas of frost in wind-sheltered locations again for Saturday
night...mainly away from the coast. Otherwise...clear skies will
prevail through the weekend. The nights will be a little bit
warmer early next week as clouds increase. A storm system will
move south into Southern California Tuesday afternoon through
Wednesday and bring rain and showers to the region. This will be
a cold storm with snow levels possibly down to 2000 to 2500 feet
at times. Fair weather will return late Thursday or Friday...but
temperatures will continue below seasonal normals.

&&

Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...

Cold airmass continues across our area with frosty conditions
likely scattered for the inland valleys this morning and even near
the coast in sheltered portions of the Oceanside area.
Northerly flow continues through Sunday but cold air will
moderate in intensity with increasing heights. The frost
advisories for early this morning and again Sunday morning for
portions of the area still look on track. Meanwhile given the
strong northerly flow there will still be gusty winds at times in
favorable offshore areas. Wind advisories continue until noon
today for areas along and west of the mountains for gusty offshore
winds.

Forecaster confidence is becoming quite high for the Tuesday
through Thursday storm...let's call it the new years evening
storm...which is looking to track over or just east of the San
Diego County warning area. Deterministic models are latching onto this scenario in
general although the most significant variances are in the exact
track of the cold core...jet and low level moisture fetch off the
ocean. Ecm and GFS are in agreement with the upper low strength
around 540 dm passing over southeast California Tuesday night and Wednesday.
Model soundings are indicating favorable for snow in the high
deserts with near saturation through around 550 mb and almost
entirely below 0c. Near saturation in the favorable dendritic
growth zone indicate the potential for a period of moderate
snowfall and relatively high snow water equivalent ratio too. For
this reason we have bumped up probability of precipitation and lowered temperatures and snow levels
for what appears to be the best timing for this scenario...late
Tuesday night through about midday Wednesday. Again still some
track issues that probably won't be resolved until we see the whites
of its eyes but do believe it is prudent to indicate the potential
for accumulating snow in locations that do not see snow very
often...possibly as low as 2000-2500 feet mainly along and east of
the mountains. For the foothills of the coastal valleys...a few
flurries will also be possible above 2000 feet however accumulating
snow less likely due to less favorable flow and moisture field...and
not as close to cold core.

Upper level system will depart Wednesday night with very cold air
likely to hang around through Friday morning especially in areas
that see snowcover. Broad east Pacific ridging and a moderating
pattern then likely through next weekend.

&&

Aviation...
271100z...clear skies and unrestricted visible through 12z sun.

Through 18z this morning...areas of NE winds 20-30 kts with higher
gusts along the coastal foothills...and mainly below canyons and
passes with associated uddfs and low level wind shear.

Some low level wind shear is expected early this morning at ksna...ending 16z-18z.
Strong NE winds are expected to remain at the surface at kont...
diminishing late morning.

&&

Marine...
300 am...areas of NE winds 15 to 20 knots with higher gusts this
morning...diminishing by afternoon. The strongest northeast winds
will be north of Oceanside and westward to San Clemente Island. A Small
Craft Advisory is in effect for wind gusts over 21 knots and locally
rough seas in this area.



&&

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



&&

Sgx watches/warnings/advisories...
California...Small Craft Advisory for winds until 7 am PST this morning for
the San Diego County coastal areas.

Wind Advisory until noon PST today for the Orange County coastal
areas...San Bernardino County mountains...San Bernardino
and Riverside County valleys-the inland Empire...Santa Ana
Mountains and foothills.

Frost advisory until 9 am PST this morning for the San
Bernardino and Riverside County valleys-the inland Empire...
San Diego County valleys.

Frost advisory until 7 am PST this morning for the San Diego
County deserts.

Frost advisory from midnight tonight to 8 am PST Sunday for the
San Diego County deserts.

Frost advisory from midnight tonight to 8 am PST Sunday for the
Coachella Valley.

Frost advisory until 8 am PST this morning for the San Diego
County coastal areas.

Wind Advisory until noon PST today for the San Diego County
mountains...San Diego County valleys.

Pz...Small Craft Advisory for winds until 7 am PST this morning for
the coastal waters from San Mateo Point to the Mexican
border and out 30 nm...waters from San Mateo Point to the
Mexican border extending 30 to 60 nm out including San
Clemente Island.



&&

$$

Public...Brotherton
aviation/marine...jad

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