Scientific Forecaster Discussion
fxus66 klox 202359
Area forecast discussion...updated
National Weather Service Los Angeles/Oxnard California
359 PM PST Tue Feb 20 2018
Another round of freezing temperatures are expected Wednesday
morning in the same areas as this morning. There is a slight
chance of light rain on Thursday. A trough of low pressure will
likely persist over the West Coast through the week with below
normal temperatures, followed by a weak ridge of high pressure on
Short term (tdy-fri)...20/125 PM.
Clear skies again tonight and what should be lighter winds and an
even drier air mass should lead to some areas being a little
cooler tonight and early Wednesday so another round of freeze
hazards are in effect. Then another cool day Wed but maybe a
degree or two warmer.
Wed and Wed night another weak trough will move through with
little to no over-water trajectory so pretty moisture starved and
mostly northwest flow aloft. Some clouds expected and continued
cool temps but likely little to no precip.
A slightly stronger/colder system will come through late Thu into
Friday but again it's mostly inland so not a lot of moisture to
work with. Could see some very light showers across slo/sb
counties, the north slopes near the Kern County line, and eastern
la County into early Thu otherwise just some clouds and
increasing west to northwest winds which will generate subsiding
air to the Lee of the mountains. Snow levels will be pretty low,
around 4000 Thu then dropping to 1500-2000 feet early Fri but
limited moisture will confine accumulations to a few inches or
less. Any precip should be tapering off Friday morning with the
exception of the Kern County line area which could see some light
precip into early afternoon with favorable wind support there.
Long term (sat-tue)...20/125 PM.
A quiet weekend expected with temperatures climbing back to near
normal levels by Sunday. Early next week another trough looks to
be taking a similar track as the last several systems though there
are some indications that it could still tap into enough moisture
to generate slightly more widespread, though mostly light precip.
Still a lot of uncertainty and the European model (ecmwf) wasn't available for
comparison so didn't make much change to the forecast. Likely cool
and breezy again, especially Mon night into Tuesday.
At 00z, the marine layer depth was around 1000 feet.
VFR conditions are expected throughout the period, except for a
chance of vlifr to LIFR conditions between 10z and 16z. There is a
chance of moderate wind shear and turbulence at ksba through 08z.
Klax...VFR conditions are expected throughout the period. Any east
winds will remain less than 7 knots.
Kbur...VFR conditions are expected throughout the period.
For the outer waters...generally high confidence in the current
forecast. Small Craft Advisory (sca) level winds are expected
through tonight, except into Wed morning for pzz676. After a lull
on Wed and Wed night, winds will likely increase to Small Craft Advisory levels
again on Thu, strengthen to Gale Warning levels Thu night then
continue at Small Craft Advisory levels Fri through sun.
For the inner waters...generally high confidence in current
forecast. For pzz645, Small Craft Advisory level winds are likely on Thu and Thu
night, with a 50% chance winds could be Gale Warning Thu
afternoon. For pzz650 and pzz655, Small Craft Advisory level winds are likely
Thursday afternoon through Friday morning, and possibly thru the
afternoon for pzz650. There is also a 50% chance of Gale Warning
level winds for pzz650 Thu night and a 20% chance of these winds
across pzz655 for Thu night into early Fri.
California...freeze warning in effect from 1 am to 9 am PST Wednesday for
zones 34>36-39-40-45-46-88-547. (See laxnpwlox).
Hard freeze warning in effect from 1 am to 9 am PST Wednesday
for zones 38-44. (See laxnpwlox).
Pz...Small Craft Advisory in effect until 3 am PST Wednesday for
zones 670-673. (See laxmwwlox).
Small Craft Advisory in effect until 9 am PST Wednesday for
zone 676. (See laxmwwlox).
Hazard potential outlook (fri-tue).
Rain and mountain snow could return to the area Thursday Friday
and again early next week, possibly making for hazardous travel
in the mountains.