Scientific Forecaster Discussion
fxus66 klox 271038
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
338 am PDT Thu Apr 27 2017
gusty northwesterly winds will continue across the region through
Friday. Afternoon temperatures will be above normal through the
weekend. There is a slight chance of light precipitation in the
Ventura and Los Angeles County mountains tonight but otherwise
dry conditions are expected through next week.
Low clouds have intruded on what was supposed to be a wind day.
Gale force winds in the outer waters spun up enough of an eddy to
bring low clouds to the San Gabriel Vly and some of the la coast.
Northwest winds have pushed clouds into the central coast and the Santa
Ynez Vly from the waters. The northerly winds have also created
clouds over all the areas near the Kern County line save for the
flat portion of the Antelope Vly. These low clouds will be
reabsorbed into the lower atmosphere either by heating or mixing
by late this morning. There do not look like there is much cirrus
upstream so aside from the areas of morning low clouds today will
be a sunny day. A warm day too with 579 hgts and offshore
northerly flow Max temps will be 3 to 6 degrees above normal
The winds are the main issue today or perhaps the lack of winds.
The north gradient from kbfl is only -4 mb and it seems like the
upper support did not pan out as strong as forecast. The San
Gabriel Vly is not going to see advisory level winds today and the
advisory was taken down. The central coast will see advisory level
gusts again this afternoon and a new advisory is in place for this
afternoon through this evening. Will let the rest of the wind
advisories and warnings limp along until later this afternoon and
tonight when they will pick up due to a stronger gradient.
The increased north flow should keep any stratus as 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 surface high moves over Nevada 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 low level wind shear/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 low level wind shear/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, Small Craft Advisory 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 Small Craft Advisory levels again. For the waters south of Point
Conception, Small Craft Advisory level west to northwest winds will continue
through Friday night. From Saturday through Monday, winds are
generally expected to remain below Small Craft Advisory levels. However, there is a
50% chance of Small Craft Advisory 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.
California...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).
Wind Advisory in effect until 9 am PDT this morning for zone
41. (See laxnpwlox).
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