Scientific Forecaster Discussion
Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
925 am PDT Thursday Oct 8 2015
Synopsis...an upper high will bring well above normal temperatures
to the region through Saturday. The peak of the heat is expected on
Friday. Gradual cooling is expected Sunday through the middle of
next week as the upper high moves westward into the Pacific and an
upper low drifts toward the forecast area from the south. This upper
low may bring showers to the area Tuesday through Wednesday.
Short term (today-sat)...high clouds this morning made for a pretty
sunrise but it appears they should be thinning out through the day
and not get in the way of our warming trend. All signs are pointing
to another 4-8 degrees of warming today in most areas. Gradients are
weakly offshore and trending further offshore and profilers all
running about 5 degrees warmer in the lower layers. No big changes
expected with the forecast today. Will probably be putting an
advisory out for northerly winds in southern sba County this evening but
it's a marginal event and will see how gradients develop through the
***From previous discussion***
North-S gradients flow across sba County should be strong enough to
bring some gusty winds to locations through and below passes and
canyons of southern sba County this evening...with winds possibly close
to advisory levels.
A strong upper high building to the west of the region today will
move into central California tonight and Friday. At the same time...the upper
low which brought showers to the region earlier this week will
retrograde from north central Mexico into northern and central Baja California
California. Low level gradients will become increasingly offshore tonight
and early Friday. Expect some gusty winds in the mountains and valleys of
l.A. And vtu counties...possibly extending into some coastal areas.
Winds should remain below advisory levels. As a result of the
offshore flow...do not expect any low clouds across the area
tonight/Fri. With stronger offshore flow...increasing thickness
values...and warming at 950 mb...all signs point to significant
warming across the region on Friday. Maximum temperatures should have no trouble
rising to a few degrees above the century mark across the warmer
valley locations in l.A. And vtu counties. Would not be surprised if
maximum temperatures got close to 100 degrees across interior sections of the
l.A. And vtu County coastal plain. Temperatures may also get close to 100
degrees across a few miles inland from the central coast due to low
level northeasterly flow in the morning.
The upper high will weaken a bit and it will be forced westward Friday
night and Sat as the upper low over northern Baja California moves off the coast.
There should be a few degrees of cooling in most areas on
Sat...especially across the central coast. Still...maximum temperatures will be
well above normal...and highs could still reach 100 degrees in the
warmer valley locations.
Long term (sun-wed)...all eyes will turn to the upper low off Baja California.
The models show this system continuing to pull away from the coast
Sunday...then show it curving nwwd on Monday...and northward toward
the region Tuesday and Wednesday. Expect a cooling trend through the
period...although maximum temperatures should still be well above normal
through at least Monday. As the upper low moves closer to the
region...it will bring at least a slight chance of
showers...possibly as early as Tuesday afternoon...with a better
chance on Wednesday. At this time...since the models continue to exhibit
run to run differences with the exact track of the upper low...will
not tinker much with the slight chance probability of precipitation currently in the
At 0600z...the marine layer inversion at klax was based at 800 feet.
The top of the inversion was 2800 feet with a temperature of 25
Overall...moderate to high confidence in the 12z taf package. Almost
all taf sites should remain VFR for the next 24+ hours. Kprb is the
exception this morning...but there is a 40 percent chance that
stratus will not develop there either. With slightly stronger
offshore flow...all taf sites should remain stratus free tonight and
Klax and kbur...high confidence in VFR conditions for the next 24+
Marine...08/900 am PDT...
Northwest winds will continue to create Small Craft Advisory
conditions from Piedras Blancas to Point Sal 10-60 nm and from Point
Sal to north of San Nicolas Island at times through Sunday. The
winds will fill in over the 0-10 nm area from Piedras Blancas to
Point Sal this evening for several hours and may return Friday
afternoon and evening. The winds will also fill in the west and
central portion of Santa Barbara Channel this afternoon and evening.
Small Craft Advisory (see laxmwwlox).