Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 261409
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
709 AM PDT Wed Apr 26 2017

.SYNOPSIS...
Gusty northerly winds will continue through Friday for portions
of Southwest California. High pressure aloft will gradually build
into the region through early next week. This combined with
offshore flow will support the warmest conditions this weekend
with cooling likely early next week as winds shift onshore.

&&

.UPDATE...

Just a quick early morning update. Have added wind advisories for
the San Fernando Valley, Santa Monica Mountains as well as the
Los Angeles Coastal areas. Latest high resolution model guidance
has increased the northerly winds initially in the San Fernando
Valley, then winds will filter through the Sepulveda pass and
Santa Monica Mtns towards West Los Angeles to the Hollywood Hills.
Winds should persist through the overnight hours. Peak gusts are
expected late this evening. Would not be surprised to see a few
gusts to 40 mph near LAX or Santa Monica, while gusts between 40
and 50 mph are expected for the San Fernando and Santa Monica
Mtns. The western portion of the San Gabriel Valley could also be
affected with local gusts to 35 mph...especially in the foothills.

&&

.SHORT TERM...(TDY-FRI)

Latest fog product imagery indicated little in the way of stratus
this morning. However, the persistent northerly flow continued to
cause some clouds to bank up against the northern slopes of the
LA/VTU/SBA County Mtns. A few sprinkles are not out of the
question across these areas this morning. More clouds should
develop across some of the interior SLO valleys around dawn for a
few hours. With the NW flow, some standing lenticular clouds
developed early Tuesday morning on the leeward side of the
Tehachapi Mtns and brought a decent amount of high clouds over
much of LA county yesterday and this could continue into today.
There will continue to be variable high clouds across the forecast
area over the next few days, but mostly sunny for most areas.

The main story over the next several days will be the continued
northerly wind episodes through at least this weekend. This
pattern is due to the broad NW upper flow over the western states
and inside slider disturbances moving through the region into the
Great Basin. Continued gusty NW to N winds are expected for the
same areas that have already been affected. Wind advisories will
continue across LA/VTU/SBA County Mtns, SBA South Coast, Antelope
Valley, Santa Clarita Valley and the Central Coast. These areas
will experience wind gusts between 35 and 50 mph for the next few
days. NW to N Winds will peak this evening across the LA/VTU
county Mtns and Antelope Valley where isolated gusts around 55 to
60 mph will be possible. Winds are expected to continue across
these same areas through Friday morning before turning offshore.
Areas not under an advisory but still quite gusty will include the
San Fernando Valley and West Los Angeles to Hollywood as north
winds could bring local gusts to 35 mph to these areas.

As far as temperatures...Expect widespread warming 3-12 degrees
with best warming expected across interior areas including the
Antelope Valley for today. A few degrees of cooking expected on
Thursday as another disturbance will move just north of the area.
With weak offshore expected on Friday, some modest warming
expected into the mid to upper 80s Friday.

.LONG TERM...(SAT-TUE)

Models are indicating an unseasonable moderate offshore wind
event for Saturday as a large upper trough digs into AZ/NM. This
will set up a pretty strong offshore gradient. Expect high temps
to reach the lower 90s in the LA/VTU coastal valleys with
widespread mid to upper 80s across LA/VTU coastal areas. Not
likely a record setting event but still 15-20 degrees above
normal. Would like to see a little better support aloft for
advisory level northeast winds but gradients alone might be enough
to generate 30-40 mph gusts in the favored areas. Cooler conds
expected for areas N of Point Conception, but still quite
pleasant...especially across the Central Coast.

Gradients quickly reverse Sunday so basically just a one day heat
event for coastal areas. Valleys will cool but still well into
the 80s. Then temps leveling off through early next week at near
to slightly above normal levels as onshore flow returns and quite
possibly some marine lyr clouds for some coastal areas Mon/Tue.

&&

.AVIATION...26/1130Z...

At 1100Z, there was no marine layer or inversion at KLAX.

Except for some patchy stratus with IFR to MVFR conds across
interior sections of SLO and SBA Counties and on northern mtn
slopes, VFR conds are expected through this evening. There may be
patchy stratus with low MVFR to high IFR conds on the Central
Coast tonight. Gusty nw to n winds will affect much of the region
through the pd with areas of LLWS and mdt to stg UDDF.

KLAX...High confidence in the 12Z TAF in that conds should be
VFR through the pd. Winds will be more tricky. There is a 10-20%
chance of Northerly cross winds over 10-15 kt through 17z this
morning, with a 20-30% chance of northerly cross winds over 15z
between 02z and 10z this evening.

BUR...High confidence in the 12Z TAF in that conds should be
VFR through the pd. There is a 30% chance of wind
gusts over 25 kt from the northwest to northeast from
mid morning through this afternoon and again tonight.

&&

.MARINE...26/325 AM

For the Outer Waters, high confidence gale force winds through
Friday night, with SCA conditions, at least,likely through
the weekend.

For the Inner Waters, moderate to high confidence in SCA conds
through Fri night. There will likely be some gale force gusts,
especially across western sections. There is a 20-30% chance that
Gale Warning may be needed, especially late Thu through Fri
evening.

Due to strong winds throughout the waters, seas will be very
choppy in all areas this week, making for hazardous boating
conditions through the week.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from noon today to 9 PM PDT this
      evening for zones 34-35. (See LAXNPWLOX).
     Wind Advisory in effect until 9 AM PDT Friday for zones
      39-52. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Friday evening for
      zones 40-41. (See LAXCFWLOX).
     Wind Advisory in effect from 3 PM this afternoon to 9 AM PDT
      Thursday for zones 41-46-547. (See LAXNPWLOX).
     Wind Advisory in effect until 6 PM PDT Thursday for zones
      53-54. (See LAXNPWLOX).
     High Wind Watch in effect from Thursday evening through
      Friday morning for zones 53-54. (See LAXNPWLOX).
     Wind Advisory in effect until 3 AM PDT Thursday for zone 59. (See LAXNPWLOX).
     Wind Advisory in effect until 3 PM PDT Friday for zone 88. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Saturday for
      zones 645-650-655. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Saturday for zones
      670-673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK...(FRI-TUE)
Gusty northeast winds are possible across portions of Los Angeles
and Ventura Counties Saturday, with well above normal
temperatures expected.

&&

$$

PUBLIC...Kaplan
AVIATION...DB
MARINE...DB
SYNOPSIS...STu

weather.gov/losangeles



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