Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 251308
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
608 AM PDT Sat Mar 25 2017
There will be a few lingering showers mostly across the mountains
today with below normal temperatures. It will be mostly sunny
Sunday with a few degrees of warming. On Monday a weak trof will
result in clouds a few light showers over SLO and Santa Barbara
counties. Gusty northerly winds will set up Monday night and
persist into Tuesday. Weak ridging aloft and northerly winds at
the surface will bring warm and dry conditions for the middle of
A weak cold front is moving through the area. It is actually a
little ahead of schedule and by dawn the showers will mostly be
confined to the mtns save for just a slight chc over LA county.
Skies away from the mtns might start off mostly cloudy but will
turn partly cloudy fairly quickly if they have not already. The
mtns will be mostly cloudy and a threat of showers will persist on
the north slopes. Rainfall amounts will be under a tenth of an
inch and more than likely just a couple of hundredths. Snow
levels will be near 6500 feet but there will not be much if any
snow accumulations. Max temps across the coasts and vlys will be
in the 60s or about 4 to 8 degrees blo normal.
A little pop up ridge will make Sunday a rather pleasant day.
Skies will be partly cloudy at worst and max temps will be up a
couple of degrees and the csts and vlys will have max temps in the
mid 60s to the lower 70s which is still a few degrees blo normal.
The inside slider that was forecast for Monday is now forecast to
be further west. Far enough west to bring a weak trof overhead
through the area. It is still weak and still pretty dry. It will
bring a chc of rain to SLO and SBA counties but only a chc of rain
over the mtns of LA and VTA counties. The clouds and the lower
hgts will contribute a few degrees of cooling.
The biggest weather news for the next 7 days will occur Monday
night and Tuesday. Good north flow both SFC and aloft along with
cool air advection will set up behind Monday`s weak trof. Strong
and gusty north winds will develop through and below the northerly
oriented passes and canyons. The i-5 corridor and the SBA south
coast will see the strongest winds. The wind speeds will be
strong advisory levels for sure and possibly warning levels. The
winds will turn to the NE during the day on Tuesday. Otherwise a
building ridge will provide clear skies and will combine with the
offshore flow to bring a 6 to 12 degree bump up in temps. There
may be a few 80 degree readings in the vlys.
The ridge peaks on Wednesday and with continued albeit weaker offshore
flow Wednesday will be the warmest day of the next 7 with all of
the vlys in the 80s and most of the coasts in the mid to upper
70s. Max temps will be 6 to 12 degrees above normal.
Big mdl differences for Thursday with the GFS continuing the
ridging and warm temps. The EC on the other hand has cooler NW
flow. GFS has been the more consistent of the mdls and favored the
warmer solution in the forecast.
Both mdls show an inside slider for Friday which will bring cooler
temps and will set up another offshore wind event.
At 1230Z, the moist layer was around 1500 ft deep. There was a
weak inversion around 2400 ft deep. The temperature at the top of
the inversion was around 11 degrees C. This is part of a
deepening moist layer.
Low confidence with 12Z TAFs. Cigs will fluctuate between VFR and
MVFR through 19z in most locations. Otherwise expect VFR conds
later this afternoon as front pushes east. There is a 40% chance
that MVFR cigs could linger near the foothills into this
afternoon. There is a 10% chance that IFR cigs will occur after
06z this eve.
KLAX...Low confidence with 12z TAF through 20z. Then better chance
for VFR with 30% chance for MVFR cigs into this afternoon. Lower
confidence with cigs after 06z this eve. Higher likelihood of
MVFR Cigs and vsbys after 08z tonight.
KBUR...Moderate confidence in 12z TAF. Cigs will fluctuate between
VFR and MVFR through this afternoon. There is a 20% chance for IFR
conds after 10z Sun morning.
Outer waters...High confidence with SCA level winds increasing
later this afternoon. Have issued SCA for the outer waters through
Sunday afternoon. 60% confidence that GALE force winds could occur
by Sunday later afternoon through early Monday morning from Pt.
Conception...through the Channel Islands and south towards San
Nicolas Island. A Gale Watch has been issued for the two lower
outer water zones Sunday late afternoon through Monday morning.
There is a high probability that strong SCA level wind gusts will
continue across much of the outer waters through Monday night with
more potential for GALE force wind gusts across the entire outer
waters Monday morning through at least Tuesday morning.
Inner waters...(From Point Sal to Point Piedras Blancas) Strongest
winds should stay across the outer waters, but 40% chance that SCA
level wind gusts could develop late this afternoon through this
evening. A better chance for SCA level wind gusts will occur on
Monday morning through Tuesday morning. For the inner waters S of
Point Conception...There will be some gusty NW to N winds across
the western portion of the SBA Channel by Sunday morning. By
Monday evening there will be gusty northerly winds across the
entire inner waters. Gusty northerly winds across the Santa Monica
Bay likely Monday evening. Offshore winds across the usual wind
prone areas from Ventura to Santa Monica then once again across
the San Pedro Channel will develop by Tue morning. 50% chance for
SCA level gusts.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
PM PDT this evening for zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect from 3 PM this afternoon to 3
PM PDT Sunday for zones 670-673-676. (See LAXMWWLOX).
Gale Watch in effect from Sunday afternoon through late
Sunday night for zones 673-676. (See LAXMWWLOX).
.HAZARD POTENTIAL OUTLOOK...(MON-FRI)
A weak weather system will bring some showers and mountain snow
showers to SLO County and the north mountain slopes on Monday.
Gusty northwest to northeast winds will affect the area at times
Monday through Friday. The winds should cause some travel issues
at times during the period. Winds may be strong enough in some
areas for small trees or tree branches to be knocked down.