Scientific Forecaster Discussion
fxus66 klox 271216
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
415 am PST Mon Feb 27 2017
the second of two relatively weak weather systems will bring cool
temperatures and a chance of rain and mountain snow today. The best
chance for rain will be in the southern portion of the forecast
area. High pressure will bring clear skies and a warming trend
Tuesday through Friday.
A small wave embedded in moist west-northwest flow will bring just a chance
of showers to the area today. The best chance for showers will be
over the mtns. Snow levels will be fairly low and the passes may
well see some flurries. A narrow slug of moisture will move into
San Diego County later this morning. While it will give San
Diego County a thorough drenching it will taper off dramatically
to the north and there is just a chance it will bring rain to
southern l.A. County. Rainfall amounts if any will be on the light
side. Skies will be cloudy and Max temps will be well below
normal with coastal and Vly temps struggling to reach 60.
Some North Slope clouds and showers will persist tonight but
otherwise it will be partly cloudy then mostly clear. Overnight
lows will be on the chilly side due to the cool airmass. There
will be some northerly canyon winds but nothing will reach
Dry northwest flow will set up over the area on Tuesday. It will be dry
and mostly sunny (partly cloudy at worst) hgts only rise to 566 dm
so while there will be a couple degrees of warming Max temps will
come in several degrees blo normal.
Weak ridging and NE offshore flow set up over the area on
Wednesday. Skies will be sunny. Hgts rise to 574 dm and Max temps
will rise 5 to 10 degrees and will mostly be a degree or two above
normal. There will be gusty morning canyon winds but there is not
enough upper or thermal support to produce upper advisory level
High pressure continues Thursday and Friday. Offshore flow peaks
Thursday and the wind gusts will likely require some low end
advisories. Max temps will be above normal each day with Friday
the warmest day of the next 7.
Both the ec and GFS agree that Saturday will be dry and also cooler
than Friday as the ridge is flattened out and the offshore flow
Trof or a ridge sunday? You choose. GFS advertises a cool trof
while the ec forecasts a very large scale ridge. Will sit back and
take a wait and see approach to this forecast. Whatever the mdl it
will be dry.
At 11z, there was no inversion at klax. There was a fairly deep
moist layer in place.
Lots of clouds and cigs across the region today. West of the
mountains, conditions will be mostly VFR, except locally MVFR at
times. In the mountains and foothills, widespread MVFR to IFR cigs
will linger through early afternoon, then conditions will improve.
There is a chance of showers today and this evening. Skies will
clear in most areas tonight.
Klax...moderate confidence in the 12z taf. There is a 20-30%
chance of MVFR cigs between 14z and 20z. These is a 20-30% chance
that easterly wind could reach 10 kt between 13z and 19z.
Kbur...moderate confidence in the 12z taf. There is a 30% chance
of MVFR cigs between 14z and 20z.
For the outer waters, high confidence in Small Craft Advisory level winds
developing this afternoon and continuing through at least late Tue
night. Current forecast. Northwest winds will likely increase to
Small Craft Advisory (sca) levels late Monday afternoon/Monday
evening and continue through Tuesday night. Winds should drop
below Small Craft Advisory levels late Tue night and Wed, then increase to Small Craft Advisory
levels Wed night or early Thu through Fri. There is a 20-30%
percent chance that there will be not much of a lull in the winds
late Tue night and Wed, and Small Craft Advisory may just linger from this
afternoon through Fri.
For the inner waters, expect winds to remain below Small Craft Advisory levels,
through Fri although confidence is not very high. In fact, there
is a 40% chance of Small Craft Advisory level winds across the northern inner
waters during the afternoon and evening hours today through Wed.
Across western portions of the sba channel, and western portions
of the southern inner waters, there is a 20-30% chance of Small Craft Advisory
conditions this afternoon and evening.
Pz...Small Craft Advisory in effect from 3 PM this afternoon to 3
am PST Wednesday for zones 670-673-676. (See laxmwwlox).
Hazard potential outlook...(wed-sun)
no significant hazards expected.