Lancaster, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

623
FXUS66 KLOX 052043
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
143 PM PDT Sun Apr 5 2026

.SYNOPSIS...04/1053 PM.

It will be a little cooler today across the coasts and lower
valleys. Today`s highs, however, will remain 10 to 12 degrees
over normal. A cooling trend will begin Monday with temperatures
back to near normal around mid week. Rain is likely sometime
between Thursday and Saturday.

&&

.SHORT TERM (TDY-WED)...05/143 PM.

Overall, 12Z models in good synoptic agreement through the short
term period. At upper levels, weak ridge will build over the area
through Tuesday then weaken on Wednesday as upper low approaches
the West Coast. At the surface, onshore gradients to the east
will increase through the period along with increasing northerly
offshore gradients.

Forecast-wise for the short term, main concern will be the winds.
With the increasing northerly offshore gradients, northerly winds
will become more widespread from day-to-day across the usual
locations (such as the Santa Ynez Range and I-5 Corridor). For
tonight, expect any northerly winds to remain below advisory
levels. However by Monday night, and continuing through Wednesday,
the chances for advisory-level winds increase. Based on HREF data,
there is about a 60-80% chance of advisory-level northerly winds
in the previously mentioned areas. So, future shifts will need to
seriously consider this possibility. As for the onshore winds, the
moderate onshore east-west gradients will generate the typical
gusty southwesterly winds across interior sections. At this time,
any advisory-level winds are expected to remain localized, mainly
confined to the desert foothills.

Other than winds, no significant issues are anticipated through
Wednesday. With the northerly flow, there is a good chance for an
eddy circulation to spin up. So, there will be some marine layer
clouds and fog across the coastal plain, mainly across the LA
coast. Also, there will be some stratus/fog across the Central
Coast. The marine inversion, itself, will remain shallow. So, if
any stratus/fog does develop, dense fog will be a concern.

As for temperatures, will expect several degrees of cooling for
most areas on Monday. For Tuesday and Wednesday, there looks to a
bit of a warming trend for the area (as the upper level ridge
peaks in strength). No matter the day-to-day changes, most areas
will remain around 6-12 degrees above normal through Wednesday.

.LONG TERM (THU-SUN)...05/143 PM.

For the extended, 12Z models continue to exhibit decent synoptic
agreement, indicating a wet and unsettled pattern as an upper low
moves across the region. Given the nature of upper lows in Spring,
confidence in the details of the storm (timing, precipitation
amounts, etc.), but there is high confidence in measurable
rainfall for the area.

The upper low, and its associated rainfall, will begin to impact
the area Thursday night/Friday with the rain chances continuing
through Saturday. On Sunday, the upper low will be south and east
of the area, but there still could be a chance of some additional
wrap-around showers (mainly across LA county). Based on WPC QPF
guidance, best forecast for now remains rainfall totals between
0.25 and 0.75 inches with local amounts around 1.00 inch. This
matches up well with GFS/ECMWF ensembles indicating a 50-70%
chance of totals between 0.50 and 1.00 inches. For amounts over
1.00 inch, ensembles indicate a 10-20% chance of that occurrence.

Along with the rainfall, there will definitely be a convective
element with this system. With any upper low in April, there is
always a concern about thunderstorms. Looking at ensemble MUCAPE,
there is a noticeable increase Friday through Saturday. Additionally,
500 MB temperatures drop to around -23 degrees Celsius. So, that
is enough to warrant a 10-20% chance of thunderstorms for all
areas in the Friday through Saturday time frame. Of course, the
exact track of the upper low will determine which areas will be
most at risk for thunderstorms, but cannot get that detailed this
far out. If thunderstorms do develop, there will be the potential
for heavy showers, strong outflow winds and hail.

&&

.AVIATION...05/1758Z.

At 1714Z at KLAX, the marine layer was 300 ft deep. The top of the
inversion was at 1500 ft with a temperature of 22 C.

High confidence in all TAFs through 06/06Z. Moderate confidence
in timing of CIG arrival and heights (+/- 200 ft) for coastal
sites.

Low confidence in KOXR & KCMA with a 25% chance of LIFR CIGs
developing between 06/10-16Z. There is also 40% chance of LIFR
CIGs at KSMO through the aforementioned timeframe.

KLAX...High confidence in TAF through 08Z. Moderate confidence
after 06/08Z. Arrival and clearing times of CIGs may be off +/-
2 hours. CIG heights could range from: 002-008. No significant
east wind component is expected.

KBUR...High confidence in VFR TAF.

&&

.MARINE...05/1059 AM.

High confidence in winds and seas remaining below Small Craft
Advisory (SCA) levels through this afternoon. SCA level winds
will develop overnight south of Point Conception and will become
widespread by Monday afternoon to include all Outer Waters,
nearshore along the Central Coast, and the Santa Barbara Channel.

SCA winds will continue across all Outer Waters through Wednesday.
Winds will diminish later in the week with moderate chances for
SCA winds lingering south of Point Conception on Thursday and
Friday. The Inner Waters will reach SCA levels at times mainly
during the afternoon and evening hours - lower chances along the
Central Coast later in the week.

There is a 30% chance of GALE force winds Wednesday night across
the Santa Barbara Channel and near the Channel Islands.

A storm system is expected to impact the coastal waters sometime
Thursday into the weekend bringing rainfall and the potential for
thunderstorms. Confidence is low on exact timing and details for
now.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM Monday to 3 AM PDT
      Tuesday for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM Monday to 3 AM PDT
      Wednesday for zones 650-670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 AM Monday to 3 AM PDT
      Wednesday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Thompson
AVIATION...Black
MARINE...Black
SYNOPSIS...30

weather.gov/losangeles

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