Area forecast discussion
National Weather Service San Diego California
155 PM PDT Tuesday Jun 18 2013
Synopsis...
upper level trough will gradually move inland along the west over
the next 24 to 48 hours...and remain in place through the weekend.
As a result...expect some only minor fluctuations in the marine
layer and temperatures the next several days...with night and
morning low clouds along the coast. Gusty west winds will develop
each afternoon and evening in the mountains and deserts.
&&
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...
Water vapor imagery shows the upper level trough slowly drifting
towards the West Coast this evening...even though the upper level
low really has not moved much in the last 4 hours. Needless to
say...the upper level trough is still poised along the West Coast
this morning...with Southern California in the dry southwesterly to
westerly flow aloft. As a result...skies are predominately sunny
this afternoon...with just some low clouds pushing back into the
beaches. That this time...most locations are within 3 degrees of
this time yesterday...and the onshore pressure gradients are
starting to increase. The upper level support at 850 mbs is 30 to
35 kts...with the main focus of these winds Riverside and San Diego
County. However...think the strongest winds will likely be through
and below the Banning pass and areas north of Interstate 10.
Therefore...a Wind Advisory will go into effect at 2 PM this
afternoon for the Banning pass.
This upper level trough will gradually move inland over the next 24
to 48 hours...with some minor cooling possible for inland areas.
However...expect only minor fluctuations in temperatures elsewhere.
An eddy will likely redevelop each night as well...but not expect
much growth in the marine layer the next several night.
However...the night and morning low clouds and fog will continue to
be possible along the coast and into the western valleys of San
Diego County. The gusty west winds will also redevelop in the
mountains and deserts each day. Although the upper level low will
shift inland across the intermountain west on Friday and this
weekend...the upper level trough will linger along the West Coast.
It will be slightly weaker...so inland areas might see some minor
warming. However...expect only minor fluctuations in temperatures
along the coast as well as in the marine layer.
There are some minor model difference for next week...as the 12z
European model (ecmwf) continues with the idea of weak troughiness over Southern
California...while the 12z GFS shows a massive ridge building into
the region from the east. Since the 12z European model (ecmwf) trended slightly
weaker with this trough though...will start the idea of warming up
the inland areas even more than the current forecast shows.
&&
Aviation...
182000z...coast/valleys...patchy stratus...with bases around 1100 feet
mean sea level and tops near 1500 feet mean sea level...will linger along the coast through
the afternoon. Low clouds will fill in over coastal aerodromes this
evening...and develop around 30 sm inland by middle Wednesday morning with
bases around 1500 feet mean sea level and tops to 2300 feet mean sea level. Visible 2-4 sm br is
expected where stratus nears higher terrain tonight. Stratus will
clear towards the coast around 17 UTC Wednesday morning.
Mtns/deserts...westerly wind gusts to 40 knots will develop over mountain
ridges and Desert Mountain slopes this evening through tonight. Locally
strong up/down drafts and low level wind shear are possible north of kpsp.
Otherwise...clear and VFR conditions will continue through Wednesday
morning.
&&
Marine...previous discussion...
a Small Craft Advisory for northwest wind gusts to 25 knots remains in effect
for the outer coastal waters this afternoon through tonight. These winds
will create a short-period combined swell up to 8 feet through the
period. Conditions may be hazardous to small craft...and will
improve early Wednesday morning.
&&
Sgx watches/warnings/advisories...
California...Wind Advisory until 3 am PDT Wednesday for the Coachella Valley.
Pz...Small Craft Advisory for winds until 3 am PDT Wednesday for the
waters from San Mateo Point to the Mexican border extending
30 to 60 nm out including San Clemente Island.
&&
$$
Public...Palmer
aviation/marine...jjt
