Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 090523
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
923 PM PST Thu Dec 8 2016
A stalled out frontal system will bring periods of light rain to
the Central Coast through Saturday night. There is a slight chance
of rain Saturday night into Sunday morning for areas south of
Point Conception. Cool conditions will continue through the
weekend, followed by slight warming early next week as high
pressure returns. There is a slight chance of rain late next week.
Broad northwest flow aloft pattern will continue across the region
during the next few days. At lower levels, a moist southwest to
west low level flow has brought period of light rain to much of
SLO and western SBA counties through the day and into this
evening. Precipitable water values up to 1.2 inches observed off
the Central Coast this evening, with even higher values further
to the west. As of 8 pm, rainfall amounts have generally ranged
between 0.25 and 1.00 inches across much of SLO county, with up to
0.25 inches across western SBA county. With ample low level
moisture and good orographic flow, the foothills and northern
coastal areas of SLO County have seen some impressive totals
with local amounts in the 1.00 to 1.50 inch range.
The focus of rainfall will continue to be across areas North of
Point Conception through Saturday night. While scattered showers
will be possible throughout this event due to the moist atmosphere
across this area, there appears to be 2 more distinct bands of
more organized light rainfall activity, occuring Friday
afternoon/evening and Saturday evening across SLO county.
For areas south of Point Conception, 00z NAM model continues
to show increasing low level moisture tonight into Friday morning.
With a little bit of lift coming across the area, would not be
surprised to see some drizzle or isolated light rainfall
accumulation across portions of Ventura/LA counties. In evening
update, have included 20 percent chance of measurable rain for
these areas but most portions of these counties will likely
not receive measurable rainfall.
With a good amount of rain already occurring across SLO and
western SBA counties through this evening, will bump up storm
total rainfall amounts through Saturday night. Much of SLO county
can now expect between 0.50 and 1.50 inches, with local 1.50 to
2.50 inches across foothill and northern coastal areas. For
the SBA Central Coast, most areas will see between 0.25 and 0.50
inches trailing off to less than 0.10 inches across Santa Barbara.
Any rainfall across Ventura and LA county expected to be very
*** From previous discussion ***
The mostly cloudy forecast tonight through Saturday for coastal
and valley areas south of Pt Conception might be a little over
done, but it will be mostly cloudy at times. Temperatures will
remain pretty consistent through Sunday, with highs generally in
the 60s in most places.
Models are in fairly good agreement that a low amplitude ridge
will build over the west coast early next week. This should result
in slightly warmer conditions, with temperatures returning to near
normal. By the end of next week, the GFS and ECMWF suggest a fast
moving upper-level trough could move through the region, possibly
bring some rain to the area. At this time, just broad brushed the
area with slight chance PoPs.
At 05Z, there was a fairly solid moist layer around 4000 ft deep,
with additional moist layers up to 15000 feet. with moist. The
top of the inversion was around 4600 ft at 11 degrees Celsius.
Widespread MVFR cigs n of Point Conception through the pd with
local IFR-LIFR conds, and occasional rain, especially north of KSMX.
S of Point Conception...cigs will lower, and there will be
widespread MVFR cigs late tonight/Fri morning with local IFR
cigs. Conds should improve to low VFR cigs in most areas by
afternoon. There will be some light rain overnight and early Fri
across VTU County and the s coast of SBA county, with a chance of
rain across L.A. County.
KLAX and KBUR...Moderate confidence in MVFR cigs from about midnight
thru Fri morning. There is a 20% chance cigs will hold off until 12z
and a 10% chance that conds will remain VFR thru the pd.
High confidence in winds staying below Small Craft Advisory (SCA)
levels everywhere through Friday. Gusty west winds will become
widespread south of Point Conception Friday afternoon through the
weekend, and a Small Craft Advisory (SCA) may be needed for those
winds (gusts to 20-25 KT) or for the steep seas (4-6 feet at 6-8
seconds) generated by the winds, especially Saturday into Sunday.
This includes the Santa Barbara Channel and Santa Monica Basin
.HAZARD POTENTIAL OUTLOOK...(SUN-THU)
Gusty northwest winds could affect Santa Barbara County and
northern Los Angeles County on Saturday or Sunday.