Frost Advisory 9, NWS Los Angeles, CA

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1036 AM PDT Tue May 10 2022

.SYNOPSIS...10/155 AM.

Cool temperatures are expected for the next few days with areas
of gusty winds and reoccurring Sundowner winds. Temperatures will
begin to warm Thursday. A significant warm up is on tap for Friday
and the weekend.

&&

.SHORT TERM (TDY-THU)...10/902 AM.

***UPDATE***

Temperatures were chilly this morning, with widespread 30s to 40s
for the mountains and interior areas of Santa Barbara and San Luis
Obispo Counties. Somewhat warmer values were further south, but
the typically cold places fell to the 20s and 30s. With this cold
airmass remaining in the region today, expecting to re-issue a
frost advisory for the San Luis Obispo interior valleys. Other
areas like the Cuyama and Santa Ynez Valleys may need frost
advisories as well. Temperatures were adjusted a few degrees
cooler in these spots, considering these morning lows. Aside from
the cold, stubborn Sundowner winds stuck around the Santa Barbara
South Coast last night, where the Montecito station reached 62
mph and Refugio Hills station peaked at 50 mph. Looks likely that
wind advisories will be needed for the Santa Barbara South Coast
tonight. Otherwise the forecast looks on track with no further
updates.

***From Previous Discussion***

A cold and dry late season upper low is over Eureka. Strong SW
flow rounding the base of the low will bring enough mid level
clouds to Srn CA this morning to make it a partly cloudy morning.
Skies should turn mostly sunny in the afternoon as the strongest
flow pushes to the south. A cold start to the morning due to the
unseasonably cool air mass and in fact a frost advisory is in
effect for the interior portion of SLO county excluding the Paso
Robles area. Gradients are weaker than on Monday and while it will
be breezy across the SBA south coast it will likely just fall
short of advisory levels. Today will likely be the coolest day of
the next 7 as max temps should fall 1 to 3 degrees from ydy's
values and end up 6 to 12 (locally 12 to 18) degrees blo normal.

The upper low and associated trof will slowly drift across Srn CA
tonight and Wednesday. While the trof is fairly sharp and there is
a decent amount of PVA the PWATs are too dry (around a quarter
inch) to support rain. Much weaker onshore flow (near neutral
actually) to the east and continued offshore flow from the north
will bring a few degrees of warming although there may be some
cooling in the interior due to falling hgts.

It will be a breezy evening on Wednesday in the wake of the trof
passage. A decent N to S gradient will set up with a little upper
and thermal support thrown in. Advisory level gusts will be
common across the majority of the SBA south coast as well as the
I-5 Corridor.

The W/E gradient turns offshore on Thursday morning as a SFC high
builds into NE Nevada. There will be about 4 mb of offshore from
both the N and the E. There will be a good amount of NE winds
across VTA and LA counties and to a lesser degree across the
Central Coast but there is not enough upper support to produce
advisory level gusts. Max temps will jump in response to the
offshore flow and rising hgts (up to 579 dam). Look for 5 to 10
degrees of warming across the board. Despite this warming max
temps will come in a degree or 2 blo normals.

Both deterministic mdls and ensemble forecasts continue to predict
an impressive ~7 mb of offshore flow from KBFL to KLAX. If this
comes to fruition a significant north wind event will develop
focused across the SBA south coast and the I-5 corridor.

.LONG TERM (FRI-MON)...10/309 AM.

GFS and EC deterministic solutions along with their respective
ensembles are all in decent agreement for the long term Friday
through Saturday. So have better than normal confidence in xtnd
fcst.

Hgts will continue to rise on Friday and on Saturday a weak ridge
will pop up raising hgts even further to about 585 dam. Weak
offshore flow from the east in the morning will turn weakly
onshore to the west in the afternoon. There will be 1 to 3 mb of
offshore flow from the north through the period. The marine layer
will be absent both days. Copious sunshine, offshore flow, and
higher than normal hgts will all combine to bring 4 to 8 degrees
of warming on Friday and 2 to 5 degrees on Saturday. Saturday now
looks to be the warmest of the next 7 with vly max temps within a
few degrees of 90. All max temps Saturday will be 5 to 10 degrees
above normal.

Upper level troffing will sweep in on Sunday. It will bring a
return of onshore flow to the east, lower hgts and the coastal
marine layer. Max temps will cool 4 to 8 degrees on Sunday
followed by 1 to 3 degrees of additional cooling on Monday. There
will be Sundowners across the SBA south coast both evenings
strongest Monday evening.

&&

.AVIATION...10/1735Z.

At 1713Z at KLAX, there was no marine layer nor inversion.

Overall, good confidence in TAFs. There is a 20% chance of MVFR
conds at KPRB late tonight. Gusty winds could cause some
turbulence, UDDFS, and LLWS near the higher terrain at times.

KLAX...Good confidence in TAF. There is a 20% chance of a 8 kt
east wind component from 07Z-16Z Wed.

KBUR...Good confidence in TAF. VFR conditions are expected.

&&

.MARINE...10/911 AM.

No changes to the marine forecast in the morning update.

For the Outer Waters, moderate confidence in current forecast.
Gale force winds are likely from Point Conception south to San
Nicolas Island, so a GALE WARNING is in effect starting this
afternoon into late tonight. There is a chance that each
afternoon and evening through Friday will see Gale force winds for
the same area. North of Point Conception will continue to see
Small Craft Advisory (SCA) level winds through Friday, with a
chance of Gale force winds Thursday afternoon. Seas will be at or
just below SCA levels through the week.

For the Inner Waters north of Point Sal, high confidence in
current forecast. Today through Friday, high confidence in SCA
level winds, especially in the afternoon and evening hours. Winds
may drop below SCA levels each morning. Seas will be at or
just below SCA levels through the week.

For the Inner Waters south of Point Conception, moderate
confidence in current forecast. Gale force wind gusts are likely across
the western portion of the Santa Barbara Channel this afternoon
and evening. Occasional gusts to 35 knots in the northwest
portion of zone 655 is possible. There is a 30-40% chance of Gale
Force gusts across the western Santa Barbara Channel again
Wednesday afternoon and evening. Otherwise, SCA level winds are
likely each afternoon and evening through Friday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 645-655-670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zones 650-673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 9 PM PDT
      this evening for zone 650. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Wednesday for zones 673-676. (See LAXMWWLOX).

&&

PUBLIC...Phillips/Rorke
AVIATION...Sweet/Lund
MARINE...Sweet/Lund
SYNOPSIS...Phillips

weather.gov/losangeles

Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
916 AM PDT TUE MAY 10 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0847 PM     NON-TSTM WND GST 2 NNW MONTECITO         34.46N 119.65W
05/09/2022  M62 MPH          SANTA BARBARA      CA   MESONET

            MESONET STATION MTIC1 MONTECITO HILLS RAWS.

&&

HALL