Rowland Heights, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

770
FXUS66 KLOX 041815
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1115 AM PDT Wed Jun 4 2025

.SYNOPSIS...04/203 AM.

Broad troughing and strong onshore flow will bring night through
morning low clouds and fog and cooler than normal temperatures
through the end of the week. A warming trend will develop for the
weekend especially away from the beaches.

&&

.SHORT TERM (TDY-FRI)...04/800 AM.

***UPDATE***

Latest satellite and surface observations indicate a widespread
blanket of low clouds, pushed into the lower coastal slopes, with
clear skies elsewhere. Current sounding data indicates marine
inversion ranging in depth from 1600 feet deep north of Point
Conception to around 2700 feet deep south of Point Conception.

Forecast-wise for the immediate short term, will be making some
slight adjustments. Looking at the high resolution models, still
some decent instability this afternoon over the eastern San
Gabriel Mountains (CAPE around 800 j/kg and K-Indices 35-40) and
PWATs are still running around one inch. So, have indicated a
slight chance of afternoon showers/thunderstorms over the eastern
San Gabriels (and the adjacent desert foothills due to southerly
steering flow). Also, would not be surprised to see some afternoon
cumulus buildups over the northern Ventura county mountains this
afternoon, but no convective precipitation as moisture is forecast
to be more limited in this area. Other than these convective
adjustments, no major changes to the immediate short term. With
moderate to strong onshore gradients today, the blanket of low
clouds will slowly dissipate through the day with many beach areas
likely to remain cloudy through the afternoon. As for winds, the
onshore gradients will generate some gusty southwesterly winds
this afternoon, especially across the desert foothills. However,
any advisory- level winds should remain very localized (in areas
like Lake Palmdale).

***From Previous Discussion***

The marine layer was disrupted last evening by all of the
convection. It has reformed and marine layer stratus now covers
all of the csts and vlys and has even pushed into some of the mtn
passes. Mdt to stg onshore flow from both the west and south (and
esp the west) will make for slow clearing today with more than few
west facing beaches likely remaining cloudy. Hgts will be rising
today as ydy`s low works its way further to the east and this
along with more sunshine will bring 3 to 6 locally 8 degrees of
warming to the area. Despite this warming max temps will end up 3
to 6 degrees blo normal.

Another trof moves into the area on Thursday. Onshore flow will
remain pretty much unchanged and again there will be plenty of
morning low clouds across the csts/vlys with slow clearing and
perhaps no clearing at some of the beaches. A few ensemble
solutions do show just enough instability and moisture to develop
some afternoon mtn convection, but for now just think there will
be some afternoon cumulus clouds. Max temps will not change much.

A high hgt (579 dam) upper low pinches off from the trof and
retrogrades to the west. It will not affect things too much, but
will create enough offshore trends in the E/W gradients to bring
better and faster clearing and 2 to 4 degrees of warming.

.LONG TERM (SAT-TUE)...04/314 AM.

Really not the best mdl agreement at the upper levels for the xtnd
period. At the sfc it looks like the strong onshore pattern will
continue so what ever the upper pattern turns out to be it will
likely not affect the persistent night through morning low cloud
pattern. Hgts do rise and this will likely smoosh the low clouds
out of some of the vlys. Also, weak offshore N to S flow develops
over the SBA county south coast which should keep that areas low
cloud free. There will be a slow warming trend through Monday when
max temp peak. Max temps across the csts will be in the 70s with
80s in the vlys. Stronger onshore flow will bring some cooling on
Tuesday.

The strong onshore flow will bring gusty near advisory winds to
the western Antelope Vly each afternoon.

&&

.AVIATION...04/1813Z.

At 1734Z at KLAX, the marine layer was 2300 feet deep. The top of
the inversion was at 4440 feet with a temperature of 17 C.

High confidence in VFR TAFs for KPMD and KWJF.

Moderate confidence in all remaining TAFs. Flight Cat change
timing could be off by +/- 2 hours. Lower confidence in forecast
for coastal TAFs for afternoon clearing (or not clearing). There
is a 20-40 percent chc of SCT conds at sites with no clearing
fcst (highest at KCMA). There is also a chc of no clearing at
KLGB (30 percent).

KLAX...Moderate confidence in TAF. There is a 20 percent chc of
SCT conds between 20Z-02Z, but low confidence in timing. There is
a 20% chc for cigs to remain above 010 through the period. No
significant east wind component is expected.

KBUR...Moderate confidence in TAF. Flight cat chances may be off
+/- 2 hours, with lowest confidence in return of cig timing.
Minimum flight cat may be off by one cat, but IFR to MVFR conds
are likely through the period.

&&

.MARINE...04/752 AM.

High confidence in unseasonably quiet conditions through Friday
with no Small Craft Advisories (SCA) needed. The thunderstorm risk
is zero today. More seasonally typical northwest to west winds
will form by Saturday or Sunday, with high confidence SCA winds
and seas over the Central Coast to San Nicolas Island waters. This
will bring short period choppy seas to the nearshore waters as
well.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Rorke/Thompson
AVIATION...Lewis
MARINE...Kittell
SYNOPSIS...30

weather.gov/losangeles

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