Scientific Forecaster Discussion
fxus66 klox 160320
Area forecast discussion...updated
National Weather Service Los Angeles/Oxnard California
820 PM PDT Sat Jun 15 2019
For Sunday into next week, clear skies are expected in interior
areas with breezy conditions over the deserts. Clouds will
increase at the coast and move further inland overnight,
persisting into the following morning. Temperatures will be
seasonal, with cooler temperatures in cloudy regions.
Short term (sat-tue)...15/655 PM.
Pretty good clearing this afternoon despite the 8.6 mb onshore
push. Clearing was a little better and earlier than yesterday
which is likely due to the weak offshore trends.
Max temps were 3 to 6 degrees blo normal across the coasts and
vlys today due to the stronger than normal onshore push but were
about 4 degrees warmer inland away from the marine layer due to
higher than normal hgts.
Tonight will be very similar to the last few with marine layer
stratus reforming after sunset and then pushing all the way to the
coastal slopes by around midnight.
Despite the strong gradient winds are not that strong except for
the Lake Palmdale area where 45 mph gusts are occuring.
Forecast is in good shape and no updates are planned.
***From previous discussion***
There is an upper-level high about 650 miles to our southwest and
the County Warning Area is under the influence of a little pop-up ridge today.
Beginning tomorrow this feature will move further southwest and an
upper-level trof will dig into our area from the northeast. By
midweek The Heights will rise back to around 590 dm and inland
temperatures will climb to normal or slightly higher. The deep
marine layer with coastal stratus will persist along the coasts
and coastal valleys, keeping things cooler than normal there.
Persistent onshore winds driven by the strong (9 mb or so at 00z)
surface pressure gradient will help keep the fog in place.
Very little day-to-day change in the sensible weather during this
period. Expect westerly winds to pick up in the Antelope Valley
by later this afternoon and northwest winds along the western
portion of the Santa Barbara South Coast.
Typical "june gloom" will continue into fathers' day with night
time clouds covering all of the coasts, valleys, and coastal
slopes. During the day the clouds will slowly retreat to the
beaches and some will clear by afternoon. Temperatures will be
similar to today's.
While an upper-level trof will be over US by Monday there will be
little noticeable change at the surface. Coastal temperatures
will not change much and some valley locations will remain about
10 degrees below normal. Inland temperatures will be similar to
A ridge over the eastern Pacific will begin to nose back into the
center of the state on Tuesday and this will lead to a decrease
in marine layer depth and less night through morning low clouds in
the coastal valleys.
Long term (wed-sat)...15/215 PM.
The upper level ridge will remain Wednesday into Thursday and
valley and interior locations will warm with the higher heights.
There will be little noticeable change along coastal sections
where the coastal stratus will persist.
Deterministic models begin to diverge a bit by Thursday, but the
general pattern should have the upper-level ridge move back out
into the Pacific and another trof moves into the area from the
Northeast. Heights will lower and the onshore flow will increase
again, driving the low clouds to cover all of the
coasts/valleys/coastal slopes. Beaches will see limited or no
clearing in the afternoon. Temperatures will fall a few degrees
everywhere and more in the valleys.
At 1730z at klax...the marine layer was 1900 feet deep. The top
of the inversion was around 4700 feet with a temperature of 21 c.
Good confidence in a persistence forecast for 00z tafs. Forceast
transitions should occur within a hour of fcst. There is a 20
percent chc of IFR cigs 10z-15z at terminals with MVFR cigs fcst.
Klax...moderate confidence in taf. Forceast transitions should
occur within a hour of fcst. There is a 20 percent chc of IFR
cigs 10z-15z. Good confidence in no east wind component greater
than 4 kt.
Kbur...moderate to high confidence in taf. Forceast transitions
should occur within a hour of fcst.
For the outer waters...good confidence in forecast through
Monday. There will be a Small Craft Advisory (sca) across the
outer waters this afternoon and evening with strongest gusts
across the far western sections of zones pzz673 and pzz676. There
is a 30% for a low end (sca) Sunday night across the southern
For the inner waters north of Point Conception. There is a 20% chance
of Small Craft Advisory level wind gusts across the western portion this evening.
Otherwise, conditions are likely to remain below Small Craft
Advisory (sca) levels through next Wednesday.
For the inner waters S of Point Conception... there is a 20
percent chance of Small Craft Advisory level winds across the far western Santa
Barbara Channel this evening. Otherwise conditions are likely to
remain below Small Craft Advisory (sca) levels through next
Pz...Small Craft Advisory in effect until 3 am PDT Sunday for
zones 670-673-676. (See laxmwwlox).
Hazard potential outlook (tue-sat).
No significant hazards expected.