Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 271110
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
410 AM PDT WED JUL 27 2016
High pressure aloft over Nevada will move little through Friday,
keeping hot weather across the region away from the coast, with
night through morning low clouds and fog confined to the coastal
plain. Slightly cooler weather is expected Saturday through
Tuesday as the upper high weakens a bit. Some monsoonal moisture
will bring a slight chance of thunderstorms to the mountains and
the Antelope Valley over the weekend.
Low clouds have pushed into coastal sections of SLO and SBA
counties, and will likely push into coastal sections of L.A. and
VTU counties by daybreak. The marine layer was running around 900
feet deep this morning. Do not expect low clouds to push into the
valleys, with the possible exception of the Santa Ynez Valleys.
Any low clouds should burn off by mid morning. Some high clouds
across nw Mexico could push into the region this afternoon in the
broad sely flow aloft. There may be enough moisture and
instability to allow for some high based cu buildups over the VTU
and L.A. County mtns and possibly the Antelope Valley this
afternoon and evening. With little change in heights/thicknesses,
temps at 850 and 950 mb, max temps today will be close to what
they were on Tue in most areas.
Strong upper level high pressure over Nevada will move little
through Fri, so expect little change in the weather across the
region. Night through morning low clouds and fog should remain
confined to the coastal plain for the most part. Sely flow aloft
will continue to be favorable for transporting some mid level
moisture into the region, but all models show that any moist
layer will remain rather shallow and confined to elevations
above 600 mb. There could be some buildups in the mtns and
Antelope Valley each afternoon, but at this point, do not expect
any showers/thunderstorms. Do not expect much change in max temps
on Thu and Fri, except for possibly just a couple of degrees of
cooling in coastal and some valley areas as onshore flow increases
The EC and GFS agree that the upper high will weaken and move
to the east over the weekend. Somewhat better moisture is
forecast to be transported into the forecast area, and while not
too impressive, the slight chance of afternoon and evening
showers and tstms for the L.A. and VTU County mtns and the
Antelope Valley looks reasonable for Sat and Sun. Max temps will
likely be down a few degrees in response to the weakening upper
A weak trough will move across nrn Ca on Monday, causing the upper
flow to turn swly, forcing any monsoonal moisture to the east
and ending any threat of tstms. Expect max temps Monday and
Tuesday to be similar to those on Sunday in most areas.
At 10z, the marine layer was around 900 feet deep at KLAX. The
top of the inversion was near 2500 feet with a temperature around
27 degrees celsius.
N of Point Conception...Moderate confidence in coastal tafs and
high confidence in KPRB taf over next 24 hours. Looks like a
persistent pattern with similar LIFR/IFR cigs and times for
stratus to develop and scour out -/+ 2 hours.
S of Point Conception...low confidence with timing of IFR cigs to
develop this morning. Not very confidence with duration of stratus
as well. SE flow aloft with some high clouds could cause stratus
to be rather chaotic and random. There will be some stratocu build
ups over the L.A. Mtns but not expecting any showers or
thunderstorms as moisture is still very elevated.
KLAX...12Z TAF...There is a 30 percent chance that IFR conditions
could be delayed a few hours from 12z taf time. VFR conditions
should redevelop between 16Z and 17z. Low confidence for timing of
IFR stratus to develop tonight into Thu morning. Some high clouds
from monsoonal flow could cause stratus to be delayed or a 20
percent chance that cigs will not develop.
KBUR...12Z TAF... High confidence in VFR conditions throughout
the 24 hour period.
Moderate confidence for only local small craft advisory level
gusts around Point Conception late this afternoon through this
evening. Overall winds should stay below small craft advisory
levels across the outer waters through this weekend. There will be
a 30 percent chance that a SCA will be needed this evening around
Point Conception and once again Thursday evening for the same
area. Otherwise expect some form of eddy to develop across the
SoCal bight over the next few night through morning hours. Nothing
too strong though. A Marine Weather Statement has been issued for
widespread dense fog for areas N of Point Conception with patchy
dense fog for areas to the south. There is a 60% chance that the
dense fog could redevelop tonight into Thursday morning across the
central coast and adjacent coastal waters N of Point Conception.