Scientific Forecaster Discussion
Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
930 am PDT Tuesday Aug 4 2015
Weak high pressure will allow for a slight warm up into mid-week.
Heading into the weekend...coastal clouds will build into the
coastal valleys each morning with considerably cooler temperatures
as low pressure passes to the north. Early next week temperatures
will rebound as high pressure builds back into the region.
Short term (today-thu)...
Not a whole lot of change made to the forecast with the morning
update. Added some clouds for areas north of pt Conception where a
narrow band of cirrus is streaming in from the SW between the upper
low about 1000 miles west of pt Conception and a ridge of high pressure
to the east. Also warmed the sba South Coast into the middle 80s for
highs this afternoon and early evening...with another round of
sundowner winds expected.
Overall today should be pretty similar to yesterday with regards to
temperatures. Areas S of pt Conception should warm a degree or two
with increasing heights/thickness values and similar onshore
gradients. Temperatures north of pt concpetion will be about the same or
possibly a couple of degrees cooler with the increase in high clouds.
Main thing to note for today is that another Wind Advisory will
likely be needed in sba County due to sundowner winds this evening
and tonight. The sba-smx gradient strengthened to -5mb last evening
and should reach similar strength tonight. Some windier locations
from last night include Gaviota and the new Refugio hills RAWS
..where gusts of 50-55 miles per hour were measured. 30-40 miles per hour winds were also
measured at los Flores Canyon and the new RAWS sensor near San
Marcos Pass. Similar winds can be expected tonight below passes and
canyons along the Santa Ynez range...with little or no wind issues
for the more heavily populated areas.
***From previous discussion***
A little pop up ridge moves into the area ahead of a dry cut off
low. There will again be a minimal marine layer. Onshore flow
relaxes and maximum temperatures will jump a 3 to 6 degrees making Wednesday
the warmest day of the week.
A little transition day on Thursday as the weak ridge leaves and the
weak upper low approaches. Still not much in the way of low clouds
in the morning. Heights will fall through the day and this will knock a
few degrees off of the temperatures.
Long term (fri-mon)... the upper low moves into Monterey County
Friday Thursday Saturday. It looks quite dry and almost all of the
dynamics stay north of the area. It will most likely only bring
partly cloudy skies to slo County but have to watch it as any upper
low can bring a few surprises. What is much more likely is the
gentle lift from the trough and the lowering heights will allow a deep
marine layer cloud pattern to form and each morning Friday and Sat low
clouds will cover the coasts and most of the valleys. Maximum temperatures will
slide downward across all areas with the biggest drops in the
previously clear valleys.
The upper low leaves and is replaced by dry SW flow between a Texas
high and a Gulf of Alaska low. Weather will be pretty dull. There
will likely be night through morning low clouds across the coasts
and lower coastal valleys. Maximum temperatures will climb a few degrees each day
as heights rebound but will still be a few degrees below normal.
At klax at 1030z there was a 800 foot deep marine layer with a
moderately strong inversion top at 2800 feet with a temperature of 26
Moderate to high confidence for valley and inland taf forecasts...fair
confidence in coastal tafs with a 20 percent chance of MVFR ceilings 12z-
Good confidence in VFR forecast for all tafs after 17z.
Klax...good confidence in 12z taf through 17z with a 30 percent chance of
bkn015. High confidence in VFR forecast 17z-08z. Fair confidence after 08z
Wednesday with a 20 percent chance of MVFR ceilings.
Kbur...high confidence in 12z taf.
Marine... 04/830 am
Across the outer waters... Small Craft Advisory conditions will
continue through late Wednesday though winds may drop below criteria
for a few hours this morning. Conditions should be below advisory
criteria Thursday and Friday then potentially increase again during
Across the inner waters... Small Craft Advisory conditions will
develop this afternoon and evening in the western half of the Santa
Barbara Channel as well as from Point Piedras Blancas to Point Sal.
Conditions should remain below advisory criteria from Wednesday
through the end of the week.
Small Craft Advisory (see laxmwwlox).