Scientific Forecaster Discussion
Southwest California area forecast discussion...updated
National Weather Service Los Angeles/Oxnard California
1035 PM PDT Friday Aug 29 2014
Updated aviation section
above normal temperatures...along with gusty evening sundowner winds
across southern Santa Barbara County...will continue through
Saturday. Overnight low clouds and fog will impact most coastal
areas through the weekend. A weak low pressure trough and increasing
onshore breezes are expected to gradually cool temperatures through
the middle of next week.
Short term (tonight-mon)...the marine inversion at lax was around
800 feet deep early this evening. Low clouds and fog were noted
along portions of the central coast this evening and are expected to
move inland across that area overnight and into the Santa Ynez
Valley after midnight. S of Point Conception...low clouds and fog
were over the socal bight mainly west and S of Santa Catalina Island
and to the san County coast. An eddy is forecast to develop
overnight which will expand the low clouds into the l.A. County
coast late tonight and possibly to the vtu County coast by daybreak.
Low clouds and fog are also expected to develop over the Salinas
River Valley in slo County late tonight. Otherwise...mostly clear
skies will prevail across the region tonight. Gusty North Canyon winds
mostly below advisory levels will affect the Santa Barbara County S
coast and mountains this evening...with gusty northwest winds across the
vtu/l.A. County mountains along the I-5 corridor...and gusty west to SW
winds in the Antelope Valley.
Upper level ridging is forecast to continue over southwestern California Sat through
Labor Day. A broad but generally weak upper level trough is expected
to move through northern California and into the Great Basin Sat and Sat night.
Except for varying amounts of night and morning low clouds and fog
for much of the coastal plain...it looks like mostly clear skies
will cover the forecast area through Labor Day. Gusty North Canyon winds
will again affect the sba S coast and mountains Sat evening...with wind
gusts possibly reaching or exceeding advisory levels in some areas.
Gusty northwest winds will also affect the vtu/l.A. County mountains especially
along the I-5 corridor Sat evening. For the Antelope Valley...gusty west
to SW winds approaching advisory levels can be expected Sat
afternoon and early evening. Support for these gusty winds will
diminish for sun. Temperatures across the region are forecast to remain
several degrees above normal on Sat...with highs around the century
mark in the warmest valleys...then gradually cool back to near normal
by Labor Day.
***From previous discussion***
Long term (tue-fri)...long range models are in pretty good synoptic
agreement overall. Tuesday through Thursday...the upper level flow
transitions to the SW as a weak upper level low develops off the
northern California coast. This should result in continued cooling...with
below normal temperatures for most areas by middle week. A deepening
marine layer and an increase in marine layer cloud coverage through
middle week seems like a good bet as well. Little change expected for
the end of the week...as the upper low stalls out off the northern
Aviation...30/0535z...widespread low clouds with IFR to LIFR conds
on the central coast should spread into the Santa Ynez Valley after
midnight...and LIFR conds should spill into the Salinas valley
overnight. Expect skies to clear in the Salinas and Santa Ynez
valleys by middle morning...and by late morning on the Coats.
S of pt Conception...expect clouds with IFR conds to push into the
l.A. County coast and possibly into the vtu County coast...with
IFR conds through middle morning Sat.
Gusty northwest-north winds through and below passes and canyons of the Santa
Ynez range and through the I-5 corridor overnight and again Sat
night...with low level wind shear and MDT uddf...possibly affecting ksba.
Klax...moderate confidence in the 06z taf...with IFR conds later
tonight through middle morning Sat. There is a 20 to 30 percent chance
that IFR conds will not materialize overnight.
Kbur...high confidence in the 06z taf with VFR conditions expected
through the period. There is a just a 10 to 20 percent chance of
MVFR visibilities between 12z and 16z.
For the outer waters...high confidence in forecast of solid Small
Craft Advisory winds through Sunday...with moderate confidence in
gales developing Saturday afternoon through late Saturday night. The
strongest winds are likely to extend over the waters southwest of
Point Conception to San Nicolas Island. Gale watch continues over
the outer waters.
For the inner waters...for Saturday afternoon and evening...higher
confidence for Small Craft Advisory level winds across the western
half of the Santa Barbara Channel. Elsewhere across the inner
waters...winds are anticipated to remain below Small Craft Advisory
levels through the weekend.
Although the southerly swell and resultant surf...will continue to
gradually diminish through the weekend...there will still be the
potential for rip currents along the local beaches this Holiday
Fire weather...29/1015 am.
Gusty sundowner winds are expected across the passes and canyons of
southern Santa Barbara County from the late afternoon through
nighttime hours through Saturday night. Wind gusts are expected to
range between 30 and 40 miles per hour with tonight's event...mostly focused
across western portions of the South Coast. Tomorrow night's event
is expected to be slightly stronger and more widespread. Wind
exposed locations and foothills will generally see humidities in the
teens with temperatures climbing to 90 degrees or above. The
combination of gusty sundowner winds...low humidities...and warm
temperatures will bring elevated fire danger to the Santa Barbara
South Coast and adjacent foothills through Saturday night...with
brief periods of critical fire weather conditions each night. Gusty
northwest winds and low humidities will also impact the Interstate 5
corridor of the Los Angeles County mountains and Antelope Valley
through Saturday night. The strongest winds for these areas are
expected late Saturday afternoon through Saturday night...when gusts
between 35 and 45 miles per hour can be expected.
Small Craft Advisory (see laxmwwlox).
High rip current risk (see laxsrflox).
Gale watch (see laxmwwlox).