Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 300127
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
627 PM PDT FRI APR 29 2016
Low pressure moving through the Great Basin will produce gusty
winds and a slight chance of showers and thunderstorms for parts
of the area this weekend. Warmer weather is expected early next
week as high pressure returns. Another low pressure system could
bring showers and cooler conditions to the area late next week.
Main impacts in the next 48-hours will be winds and isolated
mountain and desert convection. Low pressure was starting to form
over southwest Oregon this afternoon and will drop due southward
across southeast California by Saturday afternoon. Locally gusty
west winds across the Antelope Valley should increase overnight
and Saturday as a rather dry cold front moves across the area.
Moisture does stack up in northerly upslope near the Grapevine
for a few rain/snow showers there early Saturday. Also, a weak
Sundowner wind event will kick in west of Goleta along the south
Santa Barbara County coast around sunset this evening lasting until
the early morning hours. Otherwise, the marine layer and Catalina
eddy will result in low clouds and patchy fog for most coastal
areas and nearby valleys late tonight and Saturday morning.
Saturday afternoon the winds veer to northerly across the
mountains and desert, but do not extend southward much so don`t
anticipate much of a wind issue for valleys or coastal areas.
Winds may drop below advisory level fairly early tomorrow but have
extended it through the day. Slight instability over the Los
Angeles County mountains and Antelope Valley supports isolated
thunderstorm potential Saturday afternoon.
Cyclonic flow persists over southwest California on Sunday as
another piece of the trough rotates southward across the state.
Cape values increase to over 1000 j/kg across the mountains on
Sunday and if some added lift moves overhead as indicated, there
should be a greater risk of a thunderstorm in the afternoon.
Warming aloft begins Sunday night and Monday as high pressure
nudges toward the state. Expect Sunday to be the best weekend day
with lighter winds and rebounding temperatures. High pressure
ridge will become more entrenched on Monday with several degrees
of additional warming expected.
The ridge will advance eastward quickly with southwest flow aloft
developing over the area on Tuesday. Some higher level moisture
and clouds may reach the coast by Tuesday afternoon, otherwise
temperatures will be similar to Monday. An upper level front
slides over southwest California late Wednesday with the start of
cooling and additional cloud cover. Model consensus of a large and
slow-moving low pressure trough remains on-track for late in the
week, therefore, forecaster confidence is moderate to high. Just
a matter of timing for when the rain will begin over our region
but right now looks like late Thursday afternoon or maybe
Thursday night. The GFS model pushes the low pressure system
eastward faster than ECM or Canadian models and there are signs of
another closed low pressure system on the east coast blocking up
the entire pattern. Forecast trends are to keep the region fairly
unsettled Fri-Sun of next week with cooler than normal
temperatures. Have increased the chance of precipitation to high
chances on days 6-7.
Marine layer at LAX at 2300Z is 3500 feet deep and the inversion
top is at 5500 feet with a temp of 11.4 degrees C.
Another cold upper level low pressure system will dig
southeastward across interior California tonight into Saturday.
This system will reinforce the upper level northwest winds
across the forecast area. Closer to the surface...strong onshore
flow and an eddy circulation will maintain a deep marine layer
pattern into Saturday, with low clouds and fog spreading into
most coastal/valley areas. Gusty winds vcnty KSBA will generate
moderate uddfs and llws this evening.
KLAX...SCT-BKN015 conditions through the early evening hours
then MVFR cigs likely tonight into Saturday morning, with a
30 percent chance of cigs lingering into the afternoon hours.
Eddy circulation will generate se-e winds 5 to 8 knots overnight
into Saturday morning, with a 20 percent chance of reaching 10
KBUR...High probability of mvfr cigs reaching KBUR overnight into
Northwest winds and seas 10 feet or greater will create small
craft advisory conditions from Piedras Blancas to San Clemente
Island today with gale gusts tonight. Seas over 10 feet and small
craft advisory for hazadous sea conditions from Piedras Blancas to
San Clemente Island will exist through Saturday night as gales
north of the area persist. otherwise sca conditions are not
expected Sunday through Thursday. But a south swell will likely
arrive Saturday and extra currents and surging as well as
hazardous surf are likely along exposed south facing shores.
CA...Beach Hazards Statement in effect through Sunday evening For
zones 34-35. (See LAXCFWLOX).
Wind Advisory in effect until 4 AM PDT Saturday For zones
39-52. (See LAXNPWLOX).
Beach Hazards Statement in effect from Saturday morning
through Sunday evening For zones 40-41-87. (See LAXCFWLOX).
Wind Advisory in effect until 8 PM PDT Saturday For zones
53-54-59. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 11 PM PDT Saturday For
zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect until 11 PM PDT this evening
For zone 650. (See LAXMWWLOX).
Gale Warning in effect until 9 AM PDT Saturday For zones
670-673-676. (See LAXMWWLOX).
Small Craft Advisory in effect until 9 PM PDT this evening
For zone 676. (See LAXMWWLOX).