Three Points, California Weather Forecast Discussion

257
FXUS66 KLOX 141507
AFDLOX
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
807 AM PDT Sun Sep 14 2025
.SYNOPSIS...14/350 AM.
High pressure aloft centered over northern Mexico will expand into
the state and continue a warming trend through at least Tuesday.
Areas of night through morning low clouds and fog will remain a
staple of the forecast for many coast and coastal valleys through
Tuesday. Monsoonal moisture will spread into the area between
Tuesday and Wednesday and bring the possibility of showers and
thunderstorms for mid-to-late this week. A very warm and humid air
mass is likely to settle into the region during this period.
&&
.SHORT TERM (TDY-TUE)...14/353 AM.
The latest water imagery shows flat ridging in place over the
region early this morning. The low cloud field looks a little more
disorganized currently, and as a result, there is lower
confidence in the low clouds and fog for today. An upper-level
ridge of high pressure over northern Mexico will build
northwestward into the state through Tuesday, then expand across
the Great Basin and Desert Southwest into late week. A warming
trend will very likely continue across the area through Wednesday
as 500 mb heights will climb a decameter or two each day.
Weakening onshore flow is taking place across the region this
morning, and with less coverage of low clouds and fog, a warmer
day is already shaping up for today. At the surface, sub-advisory
Sundowner and Santa Lucia winds have developed overnight. Along
the Central Coast, the Santa Lucia wind regime will serve to add
some compressional heating to the warming trend today.
Confidence is higher for the best warming taking place for Monday
and Tuesday, but southeast flow aloft developing could bring some
monsoonal moisture into the region as early as Tuesday afternoon.
The flow pattern could tap into the remnants of former tropical
storm Mario as moves well south of the region. The latest
deterministic solutions favor the spread of moisture into the
region between Tuesday and Wednesday, but the forecast ensembles
lean toward any precipitation holding off until Wednesday. There
are a few solutions with precipitation as soon as Tuesday. PoPs
for Tuesday were bumped a little higher over NBM values while
emphasizing the higher terrain during the afternoon and evening
hours.
.LONG TERM (WED-SAT)...14/356 AM.
A monsoonal flow pattern looks to be wedged in across the region
between Wednesday and Thursday, and possibly into Friday and
Saturday. A more humid air mass is likely to push into the
region for mid-to-late this week, but low confidence exists in
the actual coverage of showers and thunderstorms, the forecast for
low clouds and fog, and the warming trend after Wednesday. While a
warming trend is advertised into Wednesday, any clouds that
develop could cut into daytime temperatures. Confidence is higher
for a warm and humid pattern developing with limited night through
morning low clouds and fog, but it is entirely possible that
Wednesday and part of Thursday could end up cooler under a cloud
shield.
Embedded isolated to scattered showers and thunderstorms could
develop in this pattern just about anywhere, especially during
the afternoon and evening hours, but confidence is low on the
actual placement at this time. ECMWF EFI values hint at the most
anomalous CAPE values over the coastal waters and into Santa
Barbara and San Luis Obispo Counties while ENS standardized
anomalies also advertise a similar pattern with the moisture
parameters. This would agree with deterministic GFS solutions in
highlights the best chances over the coastal waters and into the
Central Coast of California, but this all implies that model
convective schemes are working as advertised. While the presence
of a trough clipping the area will likely be the driver of the
scenario, this far out, confidence remains low to moderate.
Future shifts will need to watch this closely as there could be
potential impacts for the Gifford, Madre, and Lake burn scars. For
now, the forecast PoPs start with NBM values, but PoPs lean
higher over more typical areas in the mountains and desert.
As with any of these monsoonal moisture surges, there is a low
chance that a Flood Watch could be needed for recent burn scars.
EPS precipitable water value means approach 1.50 inches, or
nearing 99th percentile for the CFSR period for at least Wednesday
and Thursday. Any showers and thunderstorms that develop during
this period could contain brief heavy downpours, gusty and erratic
winds, and frequent lightning. Currently, the flow pattern should
allow for storms to move fairly rapidly, but future shifts will
need to take a closer look at the steering flow and the potential
for training storms over the higher terrain.
There is a decent amount of uncertainty for Friday and Saturday in
regards to how long the monsoonal moisture hangs around. While
GEFS solutions offer up more uncertainty, EPS solutions hold on to
precipitable water values near the 97th percentile into late
week. As a result, the forecast hangs onto slight chance PoPs over
the mountains and desert into next weekend.
&&
.AVIATION...14/1123Z.
At 0708 at KLAX, the marine layer was 1700 ft deep. The top of
the inversion was at 3200 ft with a temperature of 23 C.
High confidence in KPMD and KWJF TAFs.
Low to moderate confidence in all coastal and valley TAFs due to
patchy and disorganized low clouds. Timing of CIG/VSBY
restrictions may be off by 3 hours & flight categories may be off
by one cat at times when CIGs are present. Cigs may also bounce
between SCT and BKN through at least 18Z. There is a 50% chance
KSMX remains VFR through the period, and a 20% chance for LIFR to
IFR cigs at KSBP between 14Z and 17Z. There is a chance for low
clouds to arrive tonight at KSBP (15%), KSMX (30%) after 03Z.
KLAX...Moderate confidence in TAF. Cigs may SCT and reform during
the period. Clearing times may be off +/- 2 hours, and arrival
times may be off +/- 3 hours. There is a 30% chance of OVC007-009
cigs after 00Z Mon. No significant east wind component expected
through the period.
KBUR...Moderate confidence in TAF. Clearing time may be off by
+/- 90 min and arrival tonight may be off +/- 3 hours. 15% chance
for LIFR cigs after 10Z Mon. 20% chance for no low clouds
tonight.
&&
.MARINE...14/806 AM.
Small Craft Advisory (SCA) level NW winds (20-30 kts) will impact
the outer waters and the nearshore waters along the Central Coast
through early Monday morning, peaking in the afternoon and
evening hours. Gale Force wind gusts (34-38 kts) are likely this
afternoon and evening over the northern outer waters beyond 20 NM
from shore. Strongest across northeast portions of PZZ670. There
is a 20% chance of Gales nearshore along the Central Coast to 20
NM off shore. Seas will peak 7-9 feet across the northern waters
today into tonight. Conditions are expected to stay below advisory
levels on Monday and Tuesday. Low to moderate confidence in winds
increasing close to SCA levels Wednesday through Friday.
For the inner waters south of Point Conception, conditions are
generally expected to remain sub-advisory through Monday. There is
a 25% chance for WNW winds 20-25 kts across the Southern
California Bight in the afternoon and evening Tuesday, increasing
to 50% Wednesday and Thursday.
Sub-tropical moisture will move northward into the coastal waters
this week, bringing chances of showers and thunderstorms to the
area as early as Tuesday, with better chances Wednesday through
at least Friday.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from noon today to 9 PM PDT
      this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zone 670. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 9 PM PDT
      this evening for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Monday for zone
      673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Monday for zone
      676. (See LAXMWWLOX).
&&
$$
PUBLIC...Hall
AVIATION...Lewis
MARINE...Lewis/Black
SYNOPSIS...Hall
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

NWS LOX Office Area Forecast Discussion