Scientific Forecaster Discussion
fxus66 klox 011825
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
1025 am PST Wed Mar 1 2017
high pressure building in over the area will bring a warming
trend through Friday. Then, onshore flow will establish Saturday
for overnight clouds, fog, and cooler temperatures. A low pressure
system will arrive Sunday and will bring a slight chance of rain
across the central coast.
Light offshore flow has arrived. So far winds are below advisory
levels and we expect them to remain this way through at least this
evening. Stronger gradients and better upper support will arrive
later tonight into Thursday and that will give US a better chance
of at least some low end advisory level winds across the
la/Ventura mtns, valleys, and possibly parts of the coast as well.
***From previous discussion***
Thursday will be a sunny and breezy day. The winds will follow
the normal diurnal pressure curve and will subside in the
afternoon. Slightly higher hgts and better offshore flow will
provide another 3 to 6 degrees of warming and Max temps will be 4
to 8 degrees above normal.
Offshore flow will weaken as the sfc high pushes further to the
east. The upper ridge will flatten out in response to the arrival
of a pac northwest upper low. This is a change from yesterdays forecast
which had the ridge persisting. So now Max temps will not warm and
will be very similar to thursdays values.
Weak trofing will cover the West Coast on Saturday. The offshore
flow will turn onshore. Max temps will plummet by 8 to 12 degrees
and will once again be below normal.
A trof and a weak front will move into the area Sunday. North of
pt Conception there will be enough moisture and lift to produce a
chance of light rain. Rainfall if any will be on the light side.
South of pt Conception the weak lift will be enough to gin up a
shallow marine layer cloud deck. Low...mid and high clouds will
move into and over the area and the afternoon will be cloudy. Max
temps will fall another 10 degrees and most if not all areas will
struggle to even reach 60 degrees. The GFS actually holds the
front together well enough to bring rain to vta and la counties
but this seems a little too optimistic so for now will favor the
The ec and the GFS begin to diverge on Monday but there is enough
similarity to see that the day will be dry...partly cloudy and 3
to 6 degrees warmer than Sunday.
Tuesday is a question mark. Good bet on dry conditions but after
that there is little agreement between the ec and GFS. The GFS has
a ridge and is 10 degrees warmer than the troffy ec.
At 1715z, there was no marine layer to speak of around klax.
For the 18z tafs...ceiling and visibility unlimited conds are expected across the forecast
area over the next 24-hour period. Periods of moderate wind shear
and turbulence are possible between 10z and 20z at Ventura County
terminals and kvny. Less of a chance at kbur and klax.
Klax...high confidence for 18z taf in respect to VFR conditions
through the next 30-hour taf period. There is a 20 percent chance
of moderate wind shear and turbulence. East winds should remain
less than 7 knots. There is a 30 percent chance of east winds
greater than 7 knots Thu morning.
Kbur...VFR conditions are expected through the 24-hour taf
period. There is a 20 percent chance of moderate wind shear and
For the outer waters, moderate confidence winds and seas will
gradually subside through this morning. There is a 20% chance of
Small Craft Advisory level winds redeveloping this afternoon and
evening, and again Thursday afternoon and evening. There is a 50%
chance for winds to increase with Small Craft Advisory conditions
likely Friday and through the weekend.
For the inner waters, offshore winds will develop with a 40
percent chance of Small Craft Advisory level winds from Ventura
south to Santa Monica this morning nearshore between Ventura to
Malibu and across the San Pedro Channel to Avalon. There will be a
better chance with a 60% chance late tonight through Thursday
morning. For Friday through the weekend, winds and seas are
expected to remain below Small Craft Advisory levels.
Hazard potential outlook...(fri-tue)
no significant hazards expected.