Scientific Forecaster Discussion
Southwest California area forecast discussion..updated
National Weather Service Los Angeles/Oxnard California
1020 PM PDT Wednesday Aug 27 2014
Updated aviation section
High pressure will continue the warming trend through Thursday.
Gusty northwest winds are expected Thursday night and Friday night
for the Santa Barbara area. As a low pressure trough develops over
the weekend...temperatures will cool to near normal...along with the
return of the marine layer by early next week.
High pressure aloft continues to strengthen aloft this evening.
The marine layer depth has thinned to around 500 feet mean sea level as
subsidence aloft tamps down on the marine layer. With the thin
marine inversion...any low clouds and fog will likely be dense.
Weakening onshore flow will persist into Thursday. With the ridge
axis nudging closer the area...500 mb heights climb and 1000-500
mb thickness values thin. 950 mb temperatures...which initialized
well in the NAM-WRF solutions warm between 2 and 5 degrees celsius
on Thursday. The package was warmed additionally for Thursday and
Short term...the weekend temperatures should drop a couple degrees back
closer to normal levels as the ridge flattens out a bit and
onshore gradients strengthen. Increasing northwest flow offshore should
also help initiate a Little Eddy circulation which will spin up
the marine layer and bring some additional cooling to the coastal
zones. Those northwest winds will also bring some gusty sundowner winds
to the sba area starting Thursday evening and returning Friday and
likely Saturday evenings as well. Will be close to advisory level
all of those days but likely peaking Fri/Sat.
Long term...the weekend trends will continue into next week with
really no big changes expected. With highs cooling a couple
degrees each day temperatures should dip a tad below normal by Tuesday or
so. A trough will linger along the West Coast the entire week
keeping monsoon moisture well east so the thunderstorm threat is
about as close to zero as you can get.
Expect VFR conds through the period...except on the central coast
where widespread IFR to LIFR conds are expected tonight through middle
morning Thursday. Local LIFR conds could spread into the Santa Ynez
Valley as well. Expect gusty northwest-north winds through and below passes and
canyons of southern sba County Thursday evening with low level wind shear and MDT uddf near
ksba after 01z Friday.
Klax... high confidence in the 06z taf with VFR conditions expected
through the period. There is a 10 to 20 percent chance of vlifr to
LIFR conditions between 11z and 16z.
Kbur...very high confidence in the 06z taf with VFR conditions
expected through the period.
Swells from former Hurricane Marie will continue to affect the
coastal waters through Thursday. Seas across southern sections of the
outer waters...which are near Small Craft Advisory thresholds for
hazardous seas...will slowly subside late tonight.
Moderate confidence in development of Small Craft Advisory level
winds Thursday afternoon/evening across the outer waters...with
the gusty winds containing through the weekend. Across the inner
waters...winds are expected to remain below advisory
levels...also some local gusts to 25 knots will be possible
across the western half of the Santa Barbara Channel beginning
Large swells from former Hurricane Marie will continue to generate
high surf along south facing beaches through Friday. The surf will
slowly diminish Thursday and Friday. The largest surf will occur
across south facing beaches of Ventura and Los Angeles...with sets
between 10 and 15 feet and even isolated sets to 20 feet. There is
the potential for damaging and life threatening surf across south
and southeast facing shores of Los Angeles and Ventura counties.
Surf this large will have the potential to cause structural damage
and significant beach erosion. Low lying areas may also experience
some minor coastal flooding near times of high tide. In
addition...very strong rip currents and long shore currents will
likely create extremely dangerous and life threatening conditions
Although Ventura and Los Angeles counties will experience the worst
conditions...the southeast direction of the swell energy will also
bring high surf conditions and dangerous rip currents to the
southeast portion of Santa Barbara County. North of Point
Conception...the surf will not be as large...but elevated surf and
dangerous rip currents are likely across these areas also.
Small Craft Advisory (see laxmwwlox).
High surf advisory (see laxcfwlox).
High rip current risk (see laxsrflox).