Rowland Heights, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

357
FXUS66 KLOX 180555
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
955 PM PST Wed Dec 17 2025

.SYNOPSIS...17/201 PM.

Well above normal temperatures will continue away from the coast
through Friday. Unsettled weather is possible this weekend along
the Central Coast, spreading to all areas with a potentially
significant storm near the middle part of next week.

&&

.SHORT TERM (WED-SAT)...17/656 PM.

***UPDATE***

Not planning on any changes to Wind Advisories at this time. Winds
have been gusting in the 40-55 mph range on both the western and
eastern sides of the Newhall Pass. A gust to 60 was even
recorded. Some gusty winds up to 30 mph are observed across the
western coastal area of LA County, so those north winds were
strong enough to ride up and over the Santa Monicas. The dry area
has even brought a pocket of RH`s in the 30-40% range to the same
areas. LAX is currently reading 42%, and just southwest in
Manhattan Beach the RH is 91%. Quite the boundary there. North
winds will begin to weaken some within the next couple of hours.

Low clouds are spilling into the 4-County area from Kern County,
but based on Cal Trans Cameras through the Grapevine, there are
no impacts to visibility at this time. Otherwise, very low
confidence regarding low clouds tonight. Best chances are near
Paso Robles and southern LA County where northerly winds should
have limited influences, however, LAX is currently gusting to 28
mph from the northwest, so low clouds might have a very tough time
developing anywhere in LA County. Went ahead and adjusted the
clouds for tonight into tomorrow. If low clouds form anywhere near
the coasts or Paso Robles, dense fog is likely.

Remainder of the forecast looks on track.


***From Previous Discussion***

Temperatures are tracking well with fairly widespread 70s to low
80s in downsloping areas including coastal valleys and 60s so far
today most other places.

Moderate offshore flow from the north and a little upper level
support from the upper high will likely bring advisory level winds
to most of the mtns and vlys of LA/VTA county as well as the
Santa Ynez range, the Antelope Vly and the Malibu coast. The peak
of the winds should come late this afternoon and evening,
especially coastal valleys to Santa Monicas where winds have
struggled to to penetrate the stubborn marine layer.

The E/W gradient becomes more offshore on Thursday and this will
tilt the winds to the NE and set up a weak Santa Ana event. It
does not look like it will produce advisory level wind gusts. It
will limit the low clouds and fog to the Long Beach area. The
offshore flow and lack of marine layer will allow max temps across
the csts to soar 8 to 12 degree. Weaker cool air advection will
bring some warming to the interior as well. The Central Coast will
be the only cooler spot as the offshore push there will be weaker
and will allow for an earlier sea breeze. Most max temps will end
up 10 to 15 degrees above normal.

On Friday the ridge will be pushed to the south and flat westerly
flow sets up over the area. Hgts will fall to about 585 dam (still
well above normal). Low clouds will be similar to Wednesday and
pretty much confined to the Long Beach area. Much weaker offshore
flow at the sfc will lead to 3 to 6 degrees of cooling across the
csts/vlys.

Flat westerly flow will continue over the area on Saturday. Hgts
will dip to 582 dam. Onshore flow to the east and weaker offshore
flow from the north will allow for decent amount of coastal low
clouds. The southern edge of an atmospheric river (AR) affecting
the northern portion of the state may (20 percent chc) dip just
far enough to south to bring some light rain to SLO county. The
cooling trend will continue as falling hgts and better onshore
flow combine to lower most temps 3 to 6 degrees. The Central Coast
will be the exception with little change in temps. Max temps,
however, will remain above normal (well above normal across the
mtn and far interior).

.LONG TERM (SUN-WED)...17/159 PM.

The upper flow pattern changes to a more SW to NE direction on
Sunday as the AR system sags a little more to the south. A slight
chc or chc (20 to 30 percent) of rain will develop over SLO and
Western SBA counties. Other areas will just see increasing clouds.
Max temps will fall 2 to 3 degrees across almost all of the area.

The system is forecast to stall out on Monday. The 20-30 percent
chc of rain will remain over SLO and Western SBA counties.
Rainfall totals during this time will most likely be under a tenth
of an inch with perhaps the exception of the far NW tip of SLO
county which could see more. Max temps will change little from
Sunday`s values.

Things become a little more interesting on Tuesday as the AR sags
south and the flow becomes even more SW to NE. Rain chances will
overspread the entire area and now sit around 20 percent for LA
county, 30 percent for VTA county, 40 to 50 percent for SBA
county and 50 to 60 percent for SLO county. SLO county may see a
quarter inch of rain (three quarters of an inch over the extreme
NW tip) with a tenth of an inch elsewhere.

Deterministic, ensemble and AI mdls all are converging on the idea
of a large atmospheric river storm affecting the entire area
on the 24th and Christmas. There is the potential for this system
to be a big rain maker with all the attendant problems of such an
event. Early estimates place rainfall totals in the 2-4 inch range
with 4-8 inches for foothills and mountains. SoCal residents are
urged to stay as informed as possible about this developing
situation especially as it may impact holiday travel plans.

This will not be much of a snowmaker through at least early on the
25th with snow levels well above even resort levels.

Active weather with another storm or two is possible beyond our
holiday storm.

&&

.AVIATION...18/0553Z.

At 0515Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was at 3000 ft with a temperature of 22 C.

Good confidence in cig/vis fcst for all sites xcp KLAX (a 40
percent chc of LIFR conds 12Z-17Z) and KLGB (a 30 percent chc of
no low clouds)

Low confidence in wind forecasts for KSMO, KLAX, KBUR and KVNY
where winds will be gusty with variable directions and speed. Lgt
LLWS is possible at all for sites through 14Z.

KLAX...Low confidence in TAF. There is a 40 percent chc of 1SM BR
OVC003 conds 12Z-16Z. Winds will vary from 350-090 and speeds from
5kt to 15kt through 09Z. A 10 kt east wind component is possible
through 10Z then will reduce to 5kt.

KBUR... High in cig/vis fcst. Wind dir will vary from 300 to 020
through 14Z. lgt LLWS possible through 14Z.

&&

.MARINE...17/656 PM.

Small Craft Advisory (SCA) level winds expected across the outer
waters through Friday. The strongest winds are expected across an
area from near Pt Conception down to San Nicolas and westward by
about 40 NM. This area could see localized Gale Force wind gusts
through Thursday evening - SCA level winds could linger into Sat
morning. SCA level winds possible to likely at times across the
nearshore waters along the Central Coast through Friday afternoon.

Inside the southern California bight, northerly winds will
continue to impact the waters from near Malibu to Palos Verdes
through late tonight. Winds are likely impacting the San Pedro
Channel as well. SCA level W-NW wind gusts likely across the
western portion of Santa Barbara Channel each afternoon and
evening through Friday. Otherwise and elsewhere, Winds and seas
should drop below SCA levels Thursday through Sunday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 10 PM PST this evening
      for zones 88-356-362-369>375-383. (See LAXNPWLOX).
     Wind Advisory remains in effect until 4 AM PST Thursday for
      zones 349-351>353-376>381. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Thursday for
      zones 650-655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Friday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...RM/Rorke/Lewis
AVIATION...Rorke
MARINE...Black/Lewis
SYNOPSIS...RM/jld

weather.gov/losangeles

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