Alhambra, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

792
FXUS66 KLOX 200413
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
813 PM PST Fri Dec 19 2025

.SYNOPSIS...19/452 PM.

Mostly clear skies are expected through Saturday except for
overnight to morning low clouds and fog near the coast. It will
be cooler each day, but high temperatures will remain above
normal. There will be increasing clouds, cooler temperatures and
a slight chance of rain over San Luis Obispo county Sunday and
Monday. A strong storm will bring many inches of rain to the
entire area Tuesday through Wednesday.

&&

.SHORT TERM (FRI-MON)...19/812 PM.

***UPDATE***

Really not much to talk about for the update this evening. High
temperatures today were in the 60s and 70s, with the warmest
valleys in the high 70s to low 80s. Low clouds and fog have made a
return to southeast LA county, and are expected to expand
northward across the coasts, though a little less confident in the
clouds making it into the Central Coast tonight since there are
no low clouds over the nearby coastal waters.

A few degrees of cooling is expected for areas south of Point
Conception tomorrow, as onshore flow slightly increases as well as
a slight decrease in 500 mb heights. North of Point Conception, a
few degrees of warming is expected. Overall, no change in the
messaging with temperatures continuing above normal for this time
of year.

Only slight adjustment of high temps for the Central Coast
tomorrow, otherwise forecast is in shape and no other updates were
needed this evening.


***From Previous Discussion***

Overall, 12Z models in good synoptic agreement through the short
term period. At upper levels, zonal flow will prevail through
Saturday then will tilt to the southwest Sunday/Monday as the AR
begins to sag southward. Near the surface, weak onshore flow will
prevail through Monday.

Forecast-wise for the short term, no significant issues are
expected. With falling H5 heights and return of onshore flow, the
marine layer stratus will increase in depth and coverage through
the weekend, pushing into most coastal valley areas by Sunday and
Monday. Outside of the marine layer stratus, there will be
increasing mid/high level clouds through the weekend.

As the AR begins to sag southward, there will likely be some light
precipitation developing across the Central Coast, beginning
tonight and continuing through Monday. At this time, most, if any,
of the precipitation looks to be over San Luis Obispo county.
Rainfall totals will generally be around 0.10 inches or less.
However, the northwest corner of the county (think Rocky Butte)
could receive between 0.25 and 0.75 inches.

As for temperatures, the combination of increasing clouds, onshore
flow, and lowering thicknesses will bring a cooling trend for all
areas through the weekend.

Finally with respect to winds, no significant winds are
anticipated. Northerly offshore gradients will continue across the
area tonight, but will weaken. So, there will be some gusty north
winds across the Santa Ynez Range through tonight, but expect any
advisory-level winds to remain localized.

.LONG TERM (TUE-FRI)...19/210 PM.

For the extended, 12Z models differ somewhat with details, but all
generally have the same idea. A SIGNIFICANT winter storm will
impact the area during the Christmas holiday as a Pineapple
Express takes aim on the area.

As mentioned, models are still a bit out of phase with timing, so
confidence in details is moderate at best (especially with respect
to timing). However for current forecast, the peak of the AR
associated rainfall looks to occur in the Tuesday evening through
Christmas Eve night period. In this period, rain totals will
generally range between 1 and 3 inches with up to around 5 inches
across the mountains. Snow levels look to remain rather high,
above 7500 feet, through Christmas Eve.

From Christmas Day through Friday evening, a secondary shot within
the AR, as well as copious shower activity, will bring even more
rainfall to the area. In this time period, additional rainfall
totals will generally range between 1.00 and 2.50 inches with up
to around 4.00 inches in the mountains. Snow levels will drop
during this time period as colder air moves, dropping into the
6000 to 7000 foot range.

As for winds, strong and gusty southeasterly winds are likely,
beginning Tuesday and continuing through Christmas Day. The peak
winds look to occur on Christmas Eve. There is a good chance that
many areas will have at least advisory-level winds with some
mountain areas possibly getting warning-level gusts (especially
the Santa Lucia Range).

Overall, next week looks to be a very soggy and impactful holiday
week. Given the significant amount of rainfall, there will likely
be widespread hydrologic issues, including potential for mud and
debris flows and widespread urban flooding. Also, there could be
some significant winter weather issues up in the mountains. So, if
traveling on Christmas Eve or Christmas Day, be prepared for
impactful weather. Stay tuned for the latest forecast information
as the details of this pattern could change over the coming days.

&&

.AVIATION...20/0048Z.

At 2322Z, the marine layer was about 600 feet deep. The inversion
top was near 4800 feet with a temperature of 19 degrees C.

High confidence in VFR TAFs for KPMD and KWJF. Winds may gusts up
to 10 kt higher than forecast.

Low to moderate confidence in the remaining TAFs due to reduced
certainty in flight categories and timing. Lowest confidence in
KSBA with a 40% chance of LIFR/VLIFR conds after 12Z. Also lower
confidence KBUR and KVNY with a 30% chance that VFR conds prevail
through the period. Otherwise, LIFR/VLIFR conds expected during
the overnight period, and timing of flight category changes could
be off by +/- 3 hours. n

KLAX...Moderate confidence in the 00Z TAF. IFR conds expected to
reduce to LIFR/VLIFR but the flight cat changes may be off +/- 3
hours. 20% chance for vsbys under 1/2SM from 06Z-16Z. Moderate
confidence that any east wind component will remain below 8
knots.

KBUR...High confidence in the 00Z TAF through 06Z, then low
confidence through 18Z. If cigs arrive, 50% chance for vsbys less
than 1/2SM. However, 30% chance VFR conds prevail.

&&

.MARINE...19/719 PM.

Moderate to high confidence in winds and seas peaking this
evening, then decreasing to relatively calm levels by Saturday
evening through Monday across the entirety of the coastal waters.

On Tuesday, winds and seas will rapidly increase to dangerous
levels, with widespread Gale Force Winds likely, including very
strong Gales along the Central Coast. Winds will be from the SE-SW
through Thursday, then there`s a moderate chance for winds
weakening and transitioning to NW-W 15-25 kts Friday.

A short to moderate period SE-SW swell will produce steep-choppy
seas Tuesday through Thursday, transitioning to a longer period
NW-W swell by Friday. Along the Central Coast and across the
Outer Waters waves the most likely outcome are seas in the 10-16
foot range. South of Point Conception in the 6-12 foot range.

In addition to hazardous seas, rain will be continuous from
Tuesday through Thursday, with chances continuing into next
weekend.

Boaters should remain in safe harbor during this significant
storm. Unprotected south facing harbors may be especially
vulnerable to the south swell and winds.

&&

.BEACHES...19/200 PM.

A short to moderate period southerly wind swell will produce
dangerous surf and strong rip currents from Tuesday through
Thursday. A longer period NW swell will take over Friday, and
surf will continue to be significant.

There is a range of outcomes, but the most likely scenario will
yield max surf heights of 12-16 feet along the Central Coast, and
7-12 feet south of Point Conception. However, wave heights could
be a couple feet larger Tuesday through Thursday as strong
southerly winds will be occuring concurrently with the south
swell.

While peak tides are not very high, minor to potentially moderate
coastal flooding may occur, especially for south facing shores
Tuesday through Thursday.

It is best to remain out of the water during this time.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 9 AM PST Saturday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Thompson/KL
AVIATION...Ciliberti
MARINE...Lewis/Ciliberti
BEACHES...Lewis
SYNOPSIS...30/Ciliberti

weather.gov/losangeles

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