Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
200 PM PST sun Feb 7 2016
..new marine discussion...
High pressure and gusty offshore winds will bring well above
normal temperatures with possible record temperatures through early
next week. The high will weaken towards the middle of the week for a
cooling trend...however temperatures will remain above normal.
Skies were Crystal clear this afternoon with moderate to locally
strong Santa winds occurring across the usual wind prone areas. In
fact...wind gusts were already in the 40s across the Ventura
County coastal areas. Will move up the beginning of the high wind
warnings to this afternoon as opposed to this evening. Winds will
increase in response to a strong surface high strengthening over
the Great Basin. This will cause a tight surface gradient to set
up over Southern California. Latest NAM- WRF surface gradient between
lax-dag is around -9mb for 12z or (4am pst) Monday morning. This will
be mainly a gradient driven wind event with marginal upper level
support from this evening through Monday. High wind warnings are
in effect for the mountains of Los Angeles and Ventura counties
including the Santa Monica range. Also included is the Santa
Clarita valley and a portion of the Ventura valleys including Simi
Valley...to Newbury Park and cities in between...including
Westlake Village...Thousand Oaks and Moorpark. Expect sustained
winds between 25 and 40 miles per hour with gusts ranging between 60 and 70
miles per hour. Peak wind gusts will be late tonight into Monday morning.
Otherwise wind advisories will continue to be in effect for the
usual wind prone areas of Los Angeles and Ventura counties. Highs
today are expected to reach the lower to middle 80s today.
A red flag warning is also in effect for Los Angeles and Ventura
counties...excluding the Antelope Valley from 6 PM this evening
through Monday evening at 6 PM. This is due to to the strong winds and
low relative humidity. See the fire discussion below for more
Synoptically...a high amplitude ridge will persist over the
western states into the Pacific northwest through Tuesday. The ridge axis
will then shift eastward. There will continue to be a weaker ridge
of Southern California while northern California has an upper
trough moving towards the state. This will keep much of the
atmosphere warm overhead. Throw in persistent moderate offshore
winds through Tuesday and high temperatures will reach the middle to upper
80s Monday-Tuesday with a few coast and valley locations possibly
reaching 90 degrees. High temperatures will be a bit cooler across the
interior but still remain above normal for this time of year.
There could be a few heat records broken or tied including
downtown Los Angeles...ucla and Paso Robles on Monday...with more
widespread records possibly on Tuesday including downtown l.A.
By Tuesday night into Wednesday...a shortwave ridge will briefly
strengthen over much of California just ahead of the trough.
Although heights will be slightly higher...onshore flow is
expected to kick in by late Wednesday due to the proximity of the
upper trough closer to the forecast area. Best cooling will occur
across the coastal areas...with less cooling for inland areas.
Expect 4 to 8 degrees of cooling along the coast with a couple of
degrees cooling expected for inland areas. Skies should remain
mostly clear during the short period forecast.
Both the GFS and European model (ecmwf) are in good agreement that the upper ridge
will finally break down as an upper trough approaches. There will
continue to be a modest cooling trend with highs only reaching the
upper 70s by Friday. The main trough axis will move over the
forecast area on Sat/sun but will remain dry...but cooler overall. However
still above normal for this time of year. Models continue to keep
Southern California dry into at least middle February.
At 1800z at klax... the marine layer was about 600 feet deep. The
top of the inversion was near 1100 feet with a temperature of 21
High confidence in the 18z tafs. VFR conditions will prevail
throughout the forecast period. There is a 30 percent chance of low-
level wind shear and turbulence at terminals south of Point
Klax...high confidence in the 18z taf. VFR conditions will prevail
throughout the forecast period. There is a 20 percent chance of low-
level wind shear and turbulence. Any east winds will remain less
than 7 knots.
Kbur...high confidence in the 18z taf. VFR conditions will prevail
throughout the forecast period. There is a 40 percent chance of
low-level wind shear and turbulence.
A Small Craft Advisory has been issued early for the inner waters and
the winds are expected to continue into the evening before
intensifying overnight. Local gusts to 35 knots are possible Monday
morning. The gusty winds will spread into zone 676 after 10 PM.
Strongest winds are expected near shore from Ventura Harbor to Santa
Monica...however winds in excess of 20 knots could possibly spread
to eastern sections of Santa Catalina Island and Avalon Harbor as
well as The Channel islands.
No changes to previous thinking...as red flag warnings will remain
in effect for Ventura County and Los Angeles County (except for
the Antelope valley) from 600 PM this evening through 600 PM
Monday evening. Strong northeast winds along with low relative
humidity will generate critical fire weather conditions through
For Monday night and Tuesday...the offshore winds will be
weaker...but it will still be very warm and dry. So...there will
continue to be an elevated fire weather risk...and even a chance
that critical fire weather conditions may continue across sections
of Ventura and Los Angeles counties.
California...Wind Advisory in effect until 2 PM PST Monday for zones
40-41-44-547. (See laxrfwlox).
Red flag warning in effect from 6 PM this evening to 6 PM PST
Monday for zones 40-41-44>46-53-54-547-548. (See laxrfwlox).
Wind Advisory in effect until 6 PM PST this evening for zones
45-46-53-54. (See laxrfwlox).
High Wind Warning in effect from 6 PM this evening to 2 PM
PST Monday for zones 45-46-53-54. (See laxrfwlox).