000 
fxus66 klox 192207 aaa 
afdlox 


Area forecast discussion...updated 
National Weather Service Los Angeles/Oxnard California 
207 PM PST Fri Jan 19 2018 


Corrected 


Synopsis... 
low pressure will bring much cooler temperatures, gusty winds, 
and a chance of light rain and mountain snow showers to the region. 
Snow showers should linger tonight into Saturday morning on the 
north slopes, with hazardous driving conditions on the Interstate 
5 corridor around the Grapevine. Otherwise fair, breezy and cool 
weather can be expected Saturday and Sunday. Warmer conditions 
will return next week, with a slight chance of showers mainly on 
the central coast early next week. 


&& 


Short term...(tdy-mon) 


The core of a cold upper level trough is currently just off the 
northern California coast, and will swing through Southern 
California tonight. A few light showers could form anywhere for 
the rest of the day, but the flow will turn from southwest/west 
to northwest/north by this evening, and shift the focus of 
precipitation to the northern slopes and interior valleys. With 
fairly strong winds pushing low level moisture up the slopes, 
precipitation amounts should range between 0.25 and 0.50 inches, 
but amounts will be highly dependent on the terrain and therefore 
highly variable. Snow levels will be dropping through 
tonight...bottoming out around 3,000 feet. This means that the 
mountain roads, including the I-5 Tejon Pass/Grapevine should be 
impacted by accumulating snow and gusty winds. Road closures are 
possible. The central coast and eastern Los Angeles County could 
also get a few showers in this flow pattern, and cannot discount a 
stray shower drifting off the mountains into the coastal valleys 
as well. Overnight temperatures will be cool, but moderated by the 
clouds and wind. 


The gusty northerly winds will continue Saturday and Saturday 
night, but the moisture and associated precipitation chances will 
be on the decrease. While the Santa Clarita and San Fernando 
valleys, as well as the Santa Monica Mountains, should be breezy 
tonight with the northerly flow, the lax-bfl gradient does not get 
very strong and just cannot see those areas reaching advisory 
strength. So did not expand the current Wind Advisory. Those areas 
may still need to be added for Saturday afternoon and night, but 
not confident enough to do that now. Temperatures will drop 5-10 
degrees tomorrow (except for slo and sba counties which already 
saw their cooling today). Overnight temperatures Saturday night 
into Sunday will be the coldest of the week as the winds weaken 
late and the clouds go away. Some coastal valley areas will have 
some frost issues and a few frost advisories may be needed. 
Daytime Sunday should be a bit warmer with more sunshine as weak 
ridging forms aloft. 


An upper level trough will move through Washington state on 
Wednesday, with a weak front moving down the coast. There is a 
chance that this front clips slo or northern sba counties Sunday 
night into Monday before it dissapates. Otherwise, the passing 
front will bring another round of gusty northerly winds Monday 
afternoon and night that might require wind advisories in the 
mountains and sundowner country. Those winds, coupled with a quick 
pop-up ridge behind the front will actually bring a few degrees of 
noticeable warming. Coastal and valley areas might actually push 
up to normal temperatures. 


Long term...(tue-fri) 


Warmer conditions are expected Tuesday under weak ridging aloft, 
with locally breezy northerly winds. Another storm system will 
impact the area late Wednesday through early Friday. While it is 
still very early and the details will likely waver some, the 
characteristics of this storm look very similar to today's system. 
Light rain is possible Wednesday night into Thursday followed by 
lower elevation snow potentially impacting the mountain passes 
Thursday night into Friday. The winds look just as gusty, if not 
slightly stronger as well. Temperatures will fall as no surprise. 


&& 


Aviation...19/1655z... 


At 1630z, the marine inversion at klax was based at 2300 feet. The 
top of the inversion was 3600 feet with a temperature of 11 
degrees celsius. 


Overall, low to moderate confidence in 18z taf package. Weak front 
will move across the area today, bringing VFR to MVFR cigs/vsbys 
to most sites. Through the afternoon, cigs will likely bounce 
between MVFR and VFR, leading to low confidence in timing of 
flight category changes. For this evening and overnight, gusty 
north winds will develop with low level wind shear/turbulence likely at ksba as 
well as through the local mountain passes. There will be some 
northwesterly winds across the lax basin as well. 


Klax...low confidence in 18z taf. Current MVFR cigs could 
dissipate up to 3 hours earlier than current 23z forecast. There 
is a 40% chance of northerly cross winds 20 kt or greater 06z- 
18z with associated low level wind shear issues. 


Kbur...low confidence in 18z taf. Current MVFR cigs could 
dissipate up to 4 hours earlier than current 02z forecast. There 
is a 30% chance of low level wind shear/turbulence after 06z. 


&& 


Marine...19/100 PM... 


For the outer waters, moderate to high confidence in current 
forecast. 


Across the southern two outer waters zones (pzz673, pzz676), 
a Gale Warning is in effect thru Sat evening. There is a 20% 
chance that winds will remain below gale force there. 


Across the northern zone (pzz670), Small Craft Advisory conds are expected thru 
Sat night. There is a 20% chance that winds will reach gale force 
across the northern zone (pzz670) thru Sat. 


For the inner waters north of Point Sal, moderate to high confidence 
in the current forecast with Small Craft Advisory conds thru Sat night. There is a 
20% chance of gale force winds this afternoon thru Sat evening. 


Across the sba channel and the southern inner waters, moderate to 
high confidence in the forecast with gale force winds through Sat 
evening. There is a 20% chance that winds will remain below gale 
force through Sat. 


Very large northwest swell will affect all waters today and tonight, 
then swell will slowly subside Sat and Sat night. Dangerous 
breaking waves are possible near Harbor entrances, including 
morro beach Harbor and Ventura Harbor through Saturday 


&& 


Beaches...19/100 PM.... 


An extended period of large surf is expected to continue along 
west to northwest facing beaches through Saturday evening as very 
large westerly swells move through the coastal waters. 


For west and northwest facing beaches along the central coast, 
surf will average 15 to 20 feet with local sets to 25 feet today, 
then surf will slowly subside tonight through Saturday evening. A 
high surf warning remains in effect from this through 900 PM PST 
Saturday. The high surf may cause beach erosion and will produce 
life-threatening rip currents. Minor coastal flooding is possible 
in low lying areas such as parking lots, especially near the times 
of high tide, especially late this morning. 


For west and northwest facing beaches south of Point Conception, 
surf will average 8 to 12 feet today into tonight. Local sets to 
15 feet are possible on exposed west facing locations such as 
Ventura Harbor. High surf will slowly subside Saturday and 
Saturday evening. A high surf advisory remains in effect through 
900 PM PST Saturday evening. 


&& 


Lox watches/warnings/advisories... 
California...high surf warning in effect until 9 PM PST Saturday for zones 
34-35. (See laxcfwlox). 
Winter Weather Advisory in effect from 6 PM this evening to 4 
PM PST Saturday for zone 38. (See laxwswlox). 
Beach hazards statement in effect through Saturday evening 
for zone 39. (See laxcfwlox). 
Wind Advisory in effect until 10 PM PST Saturday for zone 39. (See laxnpwlox). 
High surf advisory in effect until 9 PM PST Saturday for 
zones 40-41-87. (See laxcfwlox). 
Winter Weather Advisory in effect until 4 PM PST Saturday for 
zones 52>54. (See laxwswlox). 
Wind Advisory in effect from 10 PM this evening to 10 PM PST 
Saturday for zone 59. (See laxnpwlox). 
Pz...Small Craft Advisory in effect until 3 am PST Sunday for 
zones 645-670. (See laxmwwlox). 
Small Craft Advisory in effect until 3 PM PST this afternoon 
for zones 650-655. (See laxmwwlox). 
Gale Warning in effect until 9 PM PST Saturday for zones 
650-655-673-676. (See laxmwwlox). 


&& 


Hazard potential outlook...(mon-fri) 
strong winds are possible Thursday and Friday over the mountains 
and southern Santa Barbara County. Snow and travel delays are 
possible over the Tejon Pass/Grapevine area Thursday night into 
Friday. 


&& 


$$ 


Public...kittell 
aviation...rat 



National Weather Service Glossary of Abbreviations
Back to forecast page
Non-Expanded Version (with abbreviations)

Units: English | Metric

Find the Weather for any City, State or Zipcode, or Country:

U.S. State List | Severe Weather | Tropical Storms | Ski Conditions
United States | Canada | Central America | South America | Asia | Europe | Australia | Africa | Islands

Weather Underground

© Copyright 2018
The Weather Company, LLC