Wind Advisory 42, NWS Los Angeles, CA

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
233 PM PDT Tue Apr 5 2022

.SYNOPSIS...05/855 AM.

Temperatures will be warming significantly this week with highs
in the 80s and 90s by Wednesday. Temperatures around 100 are
possible Thursday and Friday in the valleys. Gusty north to
northeast winds are expected in many areas through Thursday. A
cooling trend is expected to begin Sunday with a small chance of
rain by next Monday.

&&

.SHORT TERM (TDY-FRI)...05/151 PM.

Sunny skies prevailed early this afternoon strong northerly
gradients with some thermal support maintained gusty northerly
winds with gusts on the order of 40 to locally 60 mph focused from
the Santa Barbara mountains including the Santa Ynez range
extending into portions of the south coast, east long the Ventura
mountains and LA mountains focused near the I-5 corridor.

Model guidance is in good agreement that the strong northerly
flow will transition offshore tonight into Wednesday with offshore
flow weakening Thursday into Friday. Associated northerly wind
advisories/warnings will transition to a traditional but low end
wind advisory (to be issued later this afternoon) Ventura county
valleys to coastal areas. The coastal mountain range of San Louis
Obispo County may also need a low end with advisory for offshore
flow beginning late tonight.

The axis of a 585 dm ridge will slide overhead during the peak
offshore flow supporting 950 mb temperatures approaching 30 C as
early as Thursday and more likely by Friday. This setup will
support hot and dry conditions, most notable west of the mountains
due to compressional heating, with highs into the 90s for most.
Localized interior coastal or valley areas may peak near 100 F
Thursday or Friday, including San Gabriel, San Fernando and
perhaps even interior Santa Ynez valleys. Daily record highs
temperatures are in play, especially Friday which has more
attainable record. Even overnight lows will be on the warm side
with lows generally in the 60s, except 70s to locally 80 F for
the foothills and coastal mountain ranges. The warm overnight lows
will increase heat stress for sensitive groups, especially those
without indoor air conditioning. The current slate of heat
advisories that go into effect Wednesday looks good with no
adjustments needed at this time.

.LONG TERM (SAT-TUE)...05/208 PM.

Forecast confidence continues to be below normal during this
period especially early next week thanks to a large spread
indicated by ensemble guidance in the location and strength of a
long-wave trough. Ensemble guidance is in agreement that an
inside slider will squash the ridge south of the area by Saturday
setting up a northwest flow pattern more typical of this time of
year and perhaps spinning up an eddy south of Point Conception.
Should the eddy materialize, the marine layer could come back
with a vengeance to coastal LA and perhaps VTA counties by
Saturday morning. The northwest flow pattern will bring a return
of diurnally driven Sundowner winds focused initially across
western portions of the Santa Barbara South Coast. In either case,
onshore trends if, not outright onshore flow, combined with rapid
height falls will make the recent heat a distant memory as
temperatures return to near normal by Sunday. In fact temperatures
may crash well below normal by early next week depending on the
proximity of a deepening trough somewhere from the intermountain
West to West coast. Widespread gusty northerly winds are possible
should the trough make a nearby pass as ensemble guidance (GEFS
EPS GEPS) show is a decent possibility. A small contingent (10 to
20 percent) of guidance shows the trough sliding just enough off
the coast for a slight chance of rain and mountain snow showers.
Even the guidance that does show some chance of precipitation,
amounts and impacts would be limited at best.

&&

.AVIATION...05/1850Z.

At 1752Z at KLAX, the marine layer was around 1300 ft deep. The
top of the inversion was around 3300 ft at a temperature of 22 C.

High confidence in all TAFs. VFR conditions expected across the
region. Gusty winds from the north through tonight, and northeast
winds on Wednesday will generate turbulence, including LLWS
and UDDFS. There is a 20 percent chance of early morning marine
cloud coverage near KLGB on Wed. TAF sites that could be most
affected by LLWS include KSBA, KVNY, KBUR, KSMO, and KLAX.

Strong north winds will likely cause moderate isolated strong
turbulence, LLWS, and UDDFS through this evening. TAF sites that
could be most affected by LLWS include KSBA, KVNY, KBUR, KSMO, and
KLAX.

KLAX...Moderate confidence in TAF. There is a 30 percent chance
of 25kt of LLWS through 22Z. Good confidence that any east wind
component will be 4 kt or less.

KBUR...Good confidence in TAF. There is a 30 percent chance of 25
to 30 kts of LLWS through 22Z.

&&

.MARINE...05/204 PM.

For the Outer Waters, good confidence in current forecast with
gale force winds likely through tonight. Widespread large and
dangerous swell (10-15 ft) will develop and continue through
Wednesday.

For the Inner Waters north of Point Sal, the SCA is expected to
continue through at least this evening, but may need to be
extended since SCA level seas above 10 feet are expected to
continue into Wednesday.

For the Santa Barbara Channel, good confidence in current
forecast. While the strongest winds will be across western
section of the Channel, SCA level winds are likely across the
eastern portion during the afternoon and evening hours today.
Seas will be large and steep through late tonight.

Across the southern inner waters moderate confidence in current
forecast with a 30% chance of SCA level W-NW winds across western
sections during the afternoon and evening hours today, along with
building shorter period seas today. Good confidence in forecast
from Wednesday onward.

&&

.BEACHES...05/156 PM.

A large northwest swell from a Pacific storm will push into the
SW California coastal waters today. Surf will increase today and
Wednesday, especially on west-facing beaches. A High Surf Advisory
covers the central coast through 8 am Wednesday. A Beach Hazards
Statement covers the Ventura County coast for elevated surf during
the same period. In addition, high tide predictions are around 5
feet this week, which could generate minor beach erosion along
with the building surf.

High surf along with high temperatures in the 80s to 90s by mid-
week may lure people to area beaches for relief. Ocean water
temperatures are only in the 50s, which can easily cause
hypothermia and immediate danger to those entering the water. The
combination of high surf and cold water will be dangerous to
unprepared swimmers or surfers. Powerful waves are likely with a
high rip current risk continuing through Wednesday.

&&

&&

PUBLIC...Munroe
AVIATION...Sweet/Rorke
MARINE...Sweet/Lund
BEACHES...Sweet/DB
SYNOPSIS...Sweet/MW

weather.gov/losangeles

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