Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 231634

Area Forecast Discussion
National Weather Service San Diego CA
934 AM PDT Thu Mar 23 2017

Cool today with conditions drying out. Warmer and dry Friday, then
precipitation chances return Saturday as a weak system moves
across the area. Another system could create showers Monday or
Tuesday, then dry weather and above normal highs develop for the
middle of next week. Gusty westerly winds will develop over the
mountains and deserts as each system moves across the region.



At 9 AM PDT, water vapor satellite imagery displayed an upper-
level trough over western AZ, and a weak upper-level ridge over
northern CA. The NKX San Diego radar showed showers coming to an
end over inland portions of San Diego County. Visible satellite
showed skies clearing out from NW to SE across the region. Lower
heights and onshore flow will create westerly wind gusts of 40-50
mph over the mountains and desert mountain slopes today, along
with high temperatures 5-10 deg F below normal.

The aforementioned ridge will build over the area Friday and help
rebound high temperatures to near normal. The ridge quickly gets
squashed by an upper-level trough Saturday, lowering highs back
to 5-10 deg F below normal, and increasing chances of showers.
Coverage and strength of showers looks minimal for now as most of
the instability and moisture remain to our north. Showers will
begin over northern areas Friday night, and spread SE Saturday
morning and afternoon. Accumulations are expected to be very
light, with highest amounts near one-tenth of an inch expected
over the mountains. Snow levels will dip down to 6500 ft Saturday
morning, then rise through the day Saturday with only a dusting
expected for higher elevations. Westerly winds will gust around
35-45 mph over the mountains and deserts late Saturday. Dry
weather will develop Sunday under mostly zonal flow aloft.

Another system will move across the region sometime Monday-
Tuesday, however models disagree with timing and precip amounts.
For now, will maintain slight chance of precip on Monday, with
snow levels mostly above 7000 ft. Stronger westerly winds are
possible with this system over the mountains and deserts, with
gusts of 45-55 mph possible. Weak ridging aloft will develop for
the middle of next week, helping to raise highs to slightly above
normal. Weak offshore flow is possible as surface high pressure
builds over the Great Basin.


231501Z...SCT-BKN cloud decks within the 2000-5000 ft msl layer over
and west of the San Diego county mountains, over the Riverside
county mountains and over portions of the Inland Empire and San
Bernardino county mountains, with isolated to scattered showers,
local vis 5 sm, and mountain obscuration of coastal slopes, will
continue through 1700 UTC with showers dissipating altogether by
1800 UTC. Elsewhere, primarily P6SM vis and FEW clouds 2000-8000 ft
msl. 1800-24/0600 UTC, primarily P6SM vis all areas, FEW-SCT clouds
2000-4000 ft msl over and west of the mountains, and mostly SKC
elsewhere. 24/0600-1500 UTC, patchy BKN clouds in the 1000-3000 ft
msl layer and local vis AOB 5 sm over portions of the coast and
valley areas possible, with P6SM vis and mostly SKC elsewhere.

Through 2000 UTC, west winds 20-30 kt with gusts 35-45 kt along the
ridges and desert slopes with mod-stg up/downdrafts and LLWS over
and east of the mountains. Winds gradually weakening after 2000 UTC.


At 7 am, the San Clemente Basin Buoy showed NW winds of 23 kt
gusting 29-31 kt, with 11.5 ft seas. Meanwhile, the nearshore buoys
reported 8-10 ft seas. West-northwest winds 20-25 kt with gusts to
30 kt will continue over the coastal waters today. This, in addition
to combined seas near or above 10 ft, will create hazardous boating
conditions today. A Small Craft Advisory remains in effect for the
coastal waters through this afternoon. Winds and seas will diminish
by this evening.


Elevated surf will hit the beaches as a west northwest swell
increases across the local waters today. A Beach Hazards Statement
was issued for surf of 3 to 6 FT and strong rip currents. The surf
will gradually lower this evening.


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


CA...Beach Hazards Statement until 6 PM PDT this evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.

PZ...Small Craft Advisory until 5 PM PDT this afternoon for Coastal
     Waters from San Mateo Point to the Mexican Border and out
     to 30 nm-Waters from San Mateo point to the Mexican Border
     Extending 30 to 60 nm out including San Clemente Island.



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