Scientific Forecaster Discussion
fxus66 klox 231635
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
935 am PDT sun Apr 23 2017
dry northwest flow aloft will bring breezy conditions to the area
for most of the week. Near normal daytime temperatures expected
early this week with above normal temperatures likely later in
Good cooling this morning compared to yesterday morning with most
reporting sites in southwestern California showing five to ten
degrees cooler readings. There were some high clouds passing
overhead through the night which might have kept temperatures up a
degree or two. However the weakened offshore flow and even a
developing onshore flow in some locations has made the most
difference. Afternoon temperatures across the region will still be
above normal at most locations but will be noticeably cooler to
folks engaging in outdoor activities.
The current forecast package looks on track and few notable
changes are expected. The two parameters that will likely be
tweaked are temperatures and winds. Temperatures will be tweaked
depending upon how much they drop today and how the cooling
progresses during the next few days before it begins to warm again
into next weekend. A moderately strong northwesterly flow will set
up over the region for the next few days and wind advisories will
likely be needed for the mountains as well as northwest wind
favored canyons and valleys.
The eddy did not spin up as forecast and as a result there are not
many low clouds south of Point Conception. Northwest flow has created
some low clouds for the central coast and the Santa Ynez Vly.
Otherwise skies will be mostly sunny and Max temps will be a
couple of degrees above normal but quite a few degrees cooler than
it was yesterday. Strong northwest flow over the central coast will
create advisory level gusts this afternoon and evening. These
winds will funnel through canyons of the Santa Ynez range and
there will be advisory level gusts for the western half of the
Santa Ynez range and the sba South Coast.
Strong northwest flow will continue for Monday and Tuesday. There will
likely be advisory level gusts over the sba/vta/la mtns...the
Antelope Vly and the sba South Coast. It will be dry and mostly
clear or at worst partly cloudy with the notable exception of the
north slopes near the Kern County line on Monday night and Tuesday
morning where north flow will pile up clouds and create a slight chc
of a shower. Max temps will hover right around seasonal normals
An upper level trough will dive southeastward through the Great
Basin late Tuesday and will maintain the northwest flow across
southwest California. Wind Advisory level gusts will continue
through the period for the northwest wind prone areas, especially
across southern Santa Barbara County, the central coast, and the
mountains. The northerly flow will bring some downslope warming
to coastal/valley areas during this period, with some areas
climbing into the 80s.
Better offshore flow is forecast for next weekend. It will be
breezy and Max temps will be 5 to 10 degrees above normal.
At 1600z, the marine inversion at klax was based at 1600 feet. The
top of the inversion was 2500 feet at 17 degrees celsius.
Overall, moderate confidence in 18z taf package. Through this
evening, high confidence in VFR conditions for all sites. For
tonight, low confidence in central coast tafs remaining VFR (40%
chance of MVFR/IFR conditions 08z-17z). For the coastal tafs south
of Point Conception, low confidence in forecast as there is a
50/50 chance of conditions remaining VFR or MVFR (08z-17z).
Gusty northwest winds will continue through the taf period.
Northwest gusts to around 30 kt are likely at ksmx/ksbp 20z-04z
and westerly wind gusts around 35 kt are likely at kwjf/kpmd
Klax...moderate confidence in 18z taf. High confidence in VFR
conditions through this evening. For tonight, low confidence in
return of MVFR conditions after 10z (50% chance that airfield will
Kbur...high confidence in 18z taf. VFR conditions are anticipated
through the period (with a 20% chance of MVFR/IFR cigs 11z-16z).
For the outer waters, high confidence in current forecast. Strong
northwest winds are anticipated to continue through the week.
Currently, Gale Warning is in effect through Monday night. Gale
force winds will likely continue through Thursday although there
may be a slight lull on Tuesday.
For the inner waters, moderate confidence in current forecast. For
the waters north of Point Sal, Small Craft Advisory (sca) level
winds are expected each afternoon/evening through Thursday with a
20% chance of gale force gusts each day. For the waters south of
Point Conception, Small Craft Advisory level winds are expected each afternoon and
evening through Thursday with the strongest winds across western
sections. There will be a chance of 20% chance of gale force gusts
each day across western sections.
With the gusty winds, seas will be very choppy this week, making
for hazardous boating conditions through the week.
California...beach hazards statement in effect through Monday evening for
zones 34-35-40-41-87. (See laxcfwlox).
Wind Advisory in effect until 3 am PDT Monday for zones
34-35. (See laxnpwlox).
Wind Advisory in effect until 3 am PDT Tuesday for zones
39-52. (See laxnpwlox).
Pz...Small Craft Advisory in effect until 3 am PDT Monday for
zones 645-650. (See laxmwwlox).
Small Craft Advisory in effect from 3 PM this afternoon to 3
am PDT Monday for zone 655. (See laxmwwlox).
Gale Warning in effect until 3 am PDT Tuesday for zones
670-673-676. (See laxmwwlox).
Hazard potential outlook...(tue-sat)
very gusty north to northwest winds are expected across southern
Santa Barbara County, the central coast, the I-5 corridor, and
the Antelope Valley. Advisory level winds expected at times and
possibly exceeding warning levels, especially in the I-5 corridor
and southern sb County Wednesday and Thursday.