Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
135 PM PDT Friday Mar 14 2014
strengthening high pressure aloft along with strengthening surface
high pressure over Nevada will continue into the weekend with a
warming trend. The warming trend will spread toward the coast on
Sunday. Weak...locally moderate offshore flow will produce local
gusty northeast winds below canyons and passes at times. A trough of
low pressure moving in from the Pacific northwest into the central
and southern rockies and plains will bring onshore flow and a
cooling trend Monday and Tuesday. Weak offshore flow could develop
again late Tuesday into Thursday.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Short term (today through sunday)...
looks like the warmup has started already...with the temperature
about 5-10 degrees over yesterday in some areas. This is due to the
developing offshore flow at the surface...and also increasing high
pressure aloft. Temperatures in many areas should be above normal on
Saturday...and well above normal on Sunday. Also a bit of low
cloudiness is expected Saturday morning...then no low clouds are
expected Sunday morning.
The latest WRF cross sections are showing stronger winds at the
surface in the San Diego County mountains than the previous run for
Saturday. This may bring even stronger winds to the San Diego County
mountains than previously thought...which could push the winds into
the Wind Advisory category for Saturday in the San Diego County
mountains. We will monitor this to see if we need to issue one. Also
the Santa Ana Mountain zones could get into this category as well.
NAM BUFKIT sounding data shows potential for some low clouds at
least on the South Coast on Saturday...but dries out for Sunday.
This should coincide with a good warmup Sunday. Temperatures could
even go up into the lower 90s in the valleys and deserts...an
indicator that Spring is not far off.
European model (ecmwf) ensembles look pretty much the same as the deterministic
run...looking out through Sunday...with ridging conditions
developing. All the above support high temperatures for Sunday 15 to
20 decrees above average for the coast and valleys...and 5 to 10
degrees above average for the mountains and deserts.
Long term (monday through thursday)...
the European model (ecmwf) ensembles begins to deviate some from the deterministic
run Tuesday afternoon but both are quite similar. There
is some falling of The Heights and an onshore flow development and
cooling by Monday...continuing into Tuesday. This could bring some
low clouds back to the area by Tuesday morning...with additional
cooling. The GFS BUFKIT sounding and cross sections support coastal
low clouds on Tuesday...so they were added to the forecast. There
could be some gusty mountain and desert winds as well with the
trough. Wednesday and Thursday may see some slow warming.
142015z...coast/valleys...mostly clear with unrestricted visible through
early this evening. Better stratus development expected late
tonight...though shallower and mainly confined to the coast and
western valleys. Ceilings at coastal airports forming at or below 1500 feet mean sea level
after 15/06z...through confidence in onset timing is relatively low.
Rapid clearing of stratus Sat morning as flow begins to turn
offshore. North to northeast winds increasing Saturday evening with
areas of low level wind shear expected at kont and ksna after 15/15z.
Mtns/deserts...clear with no visible restrictions through Sat morning.
a northwest swell of 4 feet will create elevated surf south of del Mar
and strong rip currents at some beaches today. The swell will
subside through Sun morning...increasing again Sun night through Monday
as another steeply angled northwest swell of 7 feet/16-18 seconds moves in.
This will produce elevated surf for most areas...and locally strong
rip currents once again. Beaches south of del Mar...as well as
Huntington Beach...would be favored for the largest sets of 7 feet or
more on Monday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...beach hazards statement from Saturday morning through
Monday evening for the Orange County coastal areas...San
Diego County coastal areas.