Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 010325
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
825 PM PDT Sun Apr 30 2017
The onshore flow will bring an overnight marine layer and cooling to
Los Angeles coast...otherwise fair skies and above normal temperatures
through Thursday. A low may approach on Friday for possible
precipitation and cooling over the weekend.
Mostly clear skies across the region this evening. Weak offshore
flow this morning brought another very warm day across interior
sections, with warmest valley locations reaching 90 degrees.
The gradients have trended onshore this afternoon, resulting in
gusty onshore winds across the mountains and deserts which are
continuing this evening. Patchy low clouds and fog may return
to the LA county coast late tonight or Monday morning. Any fog
that does form could be locally dense due to the strong and
low inversion in place. Upper level ridge of high pressure
off the coast will continue to bring very warm temperatures
across interior sections during the next few days, with
temperatures likely peaking on Wednesday as the upper high
becomes centered over the area.
The ridge will start to move east Thursday as a trough approaches
the west coast. This will start a significant cooling trend Friday
which will continue into the weekend. The GFS and ECMWF both
develop a closed low somewhere in the vicinity of southern
California Saturday night into Sunday, but with significant
differences with respect to moisture and location. The GFS is
inland and drier while the EC is further west and wetter. Way too
early to identify a more likely scenario but increasing clouds
with a small chance of showers by Sunday seems reasonable.
At 2350Z, there was a 400 foot inversion at KLAX. The top of the
inversion was 1500 feet with a temperature of 22 degrees Celsius.
Overall, moderate to high confidence in 00Z TAF package. High
confidence in VFR conditions for all sites through this evening.
For tonight, low confidence in return of IFR/LIFR conditions to
KLAX...Overall, moderate confidence in 00Z TAF. High confidence
in VFR conditions through at least midnight. For late tonight into
early Monday morning, low confidence in return of IFR/LIFR cigs as
well as timing of return and flight category. There is a 50%
chance that conditions will remain VFR through period.
KBUR...High confidence in 00Z TAF as VFR conditions are
anticipated through the period.
For the Outer Waters, moderate confidence in current forecast.
Small Craft Advisory (SCA) level winds will likely continue
through Tuesday evening (although the winds will possibly decrease
below SCA levels on Tuesday across PZZ676). For Wednesday and
Thursday, winds and seas are expected, to remain below SCA levels,
but on Friday the winds will likely increase to SCA levels again.
For the Inner Waters, moderate confidence in current forecast. For
the waters north of Point Sal, winds are expected to remain below
SCA levels through Friday (although there is a 20% chance of SCA
level winds each afternoon/evening through Tuesday). For the
waters south of Point Conception, winds and seas are expected to
remain below SCA levels through Friday.
PZ...Small Craft Advisory in effect until 9 AM PDT Tuesday for
zones 670-673. (See LAXMWWLOX).
Small Craft Advisory in effect until 9 PM PDT Monday for zone
676. (See LAXMWWLOX).
.HAZARD POTENTIAL OUTLOOK...(WED-SUN)
No significant hazards expected.