Scientific Forecaster Discussion
fxus66 klox 241641
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
941 am PDT Mon Apr 24 2017
cooler weather for the region today with gusty northwest to north
winds in some areas. Persistent north to south pressure gradients
will keep breezy to locally windy conditions across much of the
region through at least Thursday. Temperatures will be above
normal in most areas Tuesday through Friday, then well above
normal over the weekend.
Northwest flow firmly entrenched across the area and will
continue much of the week. Tricky part of the forecast will be the
impact on the marine lyr. The most likely scenario is some patchy
low clouds north of pt Conception, but little to none in the
south. Otherwise, just the usual assortment of daily wind
advisories for the northwest favored areas and temps slightly
above seasonal norms.
***From previous discussion***
Main story will be the winds. Good N-S low level gradients, and
decent upper support with good NW winds at 850 mb and subsidence
should continue to bring advisory level winds to the Interstate-5
corridor, southern Santa Barbara County through and below passes
and canyons, and the Antelope Valley today and tonight. Expect
advisory level northwest winds to develop on the central coast
this afternoon and evening.
An upper low will drop southeastward through the pac northwest today and
tonight, then into Utah on Tuesday. Models show some decent
upslope moisture from the northerly flow pushing into the
north facing mountain slopes tonight and Tue morning, and there
will be plenty of clouds and even a slight chance of showers.
Low cloud forecast for tonight and Tue morning is difficult. The
WRF shows low level nly flow wiping out the clouds in coastal
and valley areas south of pt Conception, with stratus developing
late tonight and early Tue on the central coast as low level
northerly flow pushes against the northern slopes of the Santa
Good northwesterly flow aloft and decent N-S low level gradients
should bring continue gusty northwest to north winds to the same
areas tonight through Tuesday night, so advisories in place
through late Tue night look good. Wind advisories will likely
be needed for the central coast Tue afternoon, and possibly for
coastal sections of l.A. And vtu counties. Slight rises in
heights and thicknesses and less in the way of low clouds should
lead to a couple of degrees of warming on Tue, especially in
coastal and valley areas.
Looks like less in the way of low clouds Tue night/Wed. Max temps
should rise a few more degrees in most areas on Wed as thicknesses
and heights cont to rise.
An upper low will drop into Idaho and Montana Wed night and Thu,
then into Utah on Fri. This will cause northwesterly flow aloft
to increase across the region Thu and Fri, and with continued
sharp N-S gradients, expect gusty northwest to north winds to
continue at times through Fri. Low level moisture on northern
mountain slopes could cause a few showers again late Wed night/Thu
morning, but have held off pops for now. There will be a few
degrees in most areas Thu, with additional cooling across the mtns
and Antelope Valley on Fri.
Height and thicknesses will rise over the weekend as an upper
ridge amplifies along the West Coast. Low level flow will
turn more northeasterly by Sat, and remain offshore, though weakly
on Sunday. Max temps should jump Sat, especially west of the
mountains, with well above normal temps expected in most coastal
and valley areas next weekend.
At 1545z, the marine inversion at klax was based at 1700 feet. The
top of the inversion was 3700 feet with a temperature of 13
Overall, moderate confidence in 18z taf package. For sites north
of Point Conception, high confidence in VFR conditions through
this evening. For tonight, low confidence in return of MVFR cigs
as there is a 50% chance that conditions will remain VFR. For
coastal/valley sites south of Point Conception, there is a 40%
chance of MVFR cigs 18z-22z from koxr southward. For tonight,
moderate confidence in VFR conditions prevailing.
Gusty west to northwest winds will continue across the area.
Low level wind shear and turbulence will be issues at ksba and possibly kvny and
Klax...moderate confidence in 18z taf. There is a 20% chance of
MVFR cigs 18z-22z. High confidence in VFR conditions tonight.
Kbur...high confidence in 18z taf. There is a 15% chance of MVFR
cigs 18z-22z. There is a 30% chance of low level wind shear/turbulence after 10z.
For the outer waters, high confidence in current forecast. Strong
northwest winds are anticipated to continue through the week.
Currently, a Gale Warning is in effect through late Tuesday night.
There is a 70% chance that gale force winds will likely continue
For the inner waters, moderate to high confidence in current
forecast. For the waters north of Point Sal, strong Small Craft
Advisory (sca) level winds are expected each afternoon/evening
through Friday with a 30% chance of gale force winds developing
Tuesday through Friday. For the waters south of Point Conception,
Small Craft Advisory level winds are expected each afternoon and evening through
Friday with the strongest winds across western sections. At times
there may be gusts near gale force across western sections through
Due to strong winds throughout the waters, seas will be very
choppy this week, making for hazardous boating conditions through
California...high surf advisory in effect until 10 PM PDT this evening for
zones 34-35-40-41-87. (See laxcfwlox).
Wind Advisory in effect until 3 am PDT Tuesday for zones
34-35. (See laxnpwlox).
Wind Advisory in effect until 3 am PDT Wednesday for zones
39-52>54-59. (See laxnpwlox).
Pz...Small Craft Advisory in effect until 3 am PDT Wednesday for
zone 645. (See laxmwwlox).
Small Craft Advisory in effect from 1 PM this afternoon to 3
am PDT Wednesday for zones 650-655. (See laxmwwlox).
Gale Warning in effect until 3 am PDT Wednesday for zones
670-673-676. (See laxmwwlox).
Hazard potential outlook...(wed-sun)
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 through early Friday.