Area Forecast Discussion
Issued by NWS Los Angeles, CA
FXUS66 KLOX 271633
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
933 AM PDT Thu Apr 27 2017
A high system with offshore flow will bring fair skies...gusty winds
at times...and above normal temperatures into next week.
Still in this strong northwest wind pattern and wind advisories
and warnings continue for most of the same areas. There may be
some decrease later this morning and early afternoon but a
stronger surge is expected tonight into early Friday, especially
for LA County.
The 12z NAM continues to show a pretty robust offshore gradient
Saturday and now all the models show the upper low dropping a
little farther west than earlier in the week which will help
provide some upper level support. So confidence growing in a solid
advisory level Santa Ana event for Saturday across LA/Ventura
counties along with well above normal temps and low humidities.
***From previous discussion***
The increased north flow should keep any stratus at bay and
Friday will be a sunny day. Slightly higher hgts will translate to
1 to 3 degrees of warming across the board.
The upper level flow turns a little more to the north on Saturday
and more importantly the SFC high moves over NV and switches the
offshore flow from the north to the northeast. This looks like it
will set up moderate Santa Ana wind event with many advisory
needed for the usual windy during Santa Ana areas. This thinking
must be tempered with the realization that the mdls have been over
forecasting the winds lately. The Northeast push will warm the
coast and vly temps another 3 to 6 degrees. With the exception of
the beaches all of the coasts and vlys will see max temps in the
80s and lower 90s.
Both the GFS and the EC show a very static pattern for the xtnd
period with the state under the eastern edge of a east pac upper
high through Tuesday with hgts around 582DM. On Wednesday the
upper high pushes closer to the coast and hgts climb to 585DM.
There is varying amounts of offshore flow through the period.
Mostly likely enough to keep the low clouds away. Max temps will
continue to be 6 to 12 degrees above normal through the period
with the actual highs highly dependent on the amount of offshore
flow present on any given day. Several degrees of warming were
added to each day of the extended forecast.
At 1000Z, the marine inversion at KLAX was based around 600 feet.
The top of the inversion was 1600 feet with a temperature of 19
Overall, moderate confidence in 12Z TAF package. LIFR conditions
will come in and out of KSBP/KSMX/KPRB through 18Z this morning
with VFR conditions anticipated this afternoon and tonight. South
of Point Conception, a patch of stratus has developed over the
eastern valleys of LA County. There is a 30% chance of IFR
conditions impacting KLAX/KLGB/KSMO through 18Z with VFR
conditions anticipated this afternoon and tonight.
Gusty northwest to north winds will continue through the TAF
period with the potential for LLWS/turbulence at coastal and
valley TAF sites through this evening.
KLAX...moderate confidence in 12Z TAF. There is a 30% chance of
IFR conditions 12Z-18Z. There is a 30% chance of northerly cross
winds after 22Z.
KBUR...high confidence in 12Z TAF. VFR conditions are anticipated
through the period. There is a 40% chance of LLWS/turbulence
issues through the TAF period.
For the Outer Waters, high confidence in current forecast. Gale
force winds will continue through Friday night then subside to
Small Craft Advisory (SCA) levels Saturday through Monday.
For the Inner Waters, moderate to high confidence in current
forecast. For the waters north of Point Sal, SCA level winds will
continue through Friday night before subsiding on Saturday.
However for Sunday and Monday, there is a 60% chance of winds
increasing to SCA levels again. For the waters south of Point
Conception, SCA level west to northwest winds will continue
through Friday night. From Saturday through Monday, winds are
generally expected to remain below SCA levels. However, there is a
50% chance of SCA level northeast winds Saturday from Ventura
south to Santa Monica.
Due to strong winds throughout the waters, seas will be very
choppy in all areas this week, making for hazardous boating
conditions through the week.
CA...Wind Advisory in effect from 1 PM this afternoon to 9 PM PDT
this evening for zones 34-35. (See LAXNPWLOX).
Wind Advisory in effect until 9 AM PDT Friday for zones
39-44>46-52-59-547. (See LAXNPWLOX).
Beach Hazards Statement in effect through Friday evening for
zones 40-41. (See LAXCFWLOX).
High Wind Warning in effect until 9 AM PDT Friday for zones
53-54. (See LAXNPWLOX).
Wind Advisory in effect until 3 PM PDT Friday for zone 88. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Saturday for
zones 645-650-655. (See LAXMWWLOX).
Gale Warning in effect until 3 AM PDT Saturday for zones
670-673-676. (See LAXMWWLOX).
.HAZARD POTENTIAL OUTLOOK...(SAT-WED)
Gusty northeast winds are possible across portions of Los Angeles
and Ventura Counties Saturday, with well above normal