Scientific Forecaster Discussion
Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
855 am PDT Wednesday Oct 7 2015
High pressure and offshore winds will bring above normal
temperatures through early next week with the heat peaking from
Friday into the weekend. A slight cooling trend will begin early
next week as the high weakens. A low may approach from the southwest
on Tuesday with possible precipitation and additional cooling.
Short term (today-sat)...
*** middle morning discussion update ***
Another morning of warming temperatures with some locations already
double digits ahead of this time yesterday. Still is a pleasant
morning with near normal temperatures and partly cloudy skies.
Temperatures remain on track to continue rising steadily through
Friday which will result in another hot weekend for the region. The
hot temperatures will be poked up a bit by elevated offshore winds
that will be more notable by tomorrow in San Luis Obispo and across
the service area by Friday.
Next week continues to look wet with precipitation moving back into
the region though how much precipitation is very much in question. Also
how it moves through... whether up from the south or in from the
west. An interesting low center movement to be sure. For now no
big changes are anticipated to the forecast package.
*** Early morning discussion ***
Weak offshore flow is keeping skies clear across the area save for
some patchy low clouds near Santa Maria. Otherwise heights will climb
to 588 dm and this with offshore flow will allow maximum temperatures to climb
into 80s across most coasts and valleys with a smattering of 90s in the
valleys and some 70s and the beaches.
There will be slight eddy form overnight which stands a fair chance
of bring some low clouds to the lgb-lax area. There will be weak
offshore flow but the lgb-lax area is the one area that is affected
least by offshore flow. That said there is a decent chance of skies
remaining clear all night long. There will be a weak sundowner as
well and this will keep some overnight lows along the sba South
Coast in the 70s. Otherwise skies will be clear and heights will climb
t0 591 dm. The best offshore flow will be across the central coast
and maximum temperatures there will all be in the middle 80s to lower 90s. South
of Point Conception maximum temperatures will bump up a few more degrees and
will be 8 to 12 degrees above normal.
Upper ridging and offshore flow peak Friday and Saturday with 594 mb
heights and 4 mb or so of offshore flow. There will be some canyon
breezes but more than likely they will not reach advisory levels.
Maximum temperatures will soar and almost all of the csts and valleys will be
in the upper 80s and 90s. There will be some triple digit readings
in the warmest spots and even the beaches will reach to the lower
80s. Areas near the breezy canyons will see overnight lows in the
70s...but areas away from the winds will have good overnight cooling
as the clear skies...dry air and 12+ hours of darkness combine. The
only Silver lining with this heat outbreak is that there will be
little humidity so it will not feel as bad as it did several weeks
The lower humidity values along with the canyon winds will make for
a two day period of elevated fire danger.
Long term (sun-tue)... the ridge breaks down sun and Monday as a large
upper low (in fact and remarkably the same upper low that brought US
the rain on Sunday. As it boomerangs back at US by way of New Mexico
and northern mexico) this will bring noticeable cooling Sunday and just a
little more cooling Monday. Still maximum temperatures will remain above normal.
Tuesdays forecast is a little bit of a mystery and depends on the
exact track of the upper low. There is a slight chance it will bring
some showers to the area in the afternoon but more than likely any
rain associated with this system will hold off until Wednesday. Temperatures
will cool a few more degrees.
At 1100z...there was no marine inversion at klax.
Except for patchy low clouds and locally dense fog on the central
coast...with LIFR to vlifr conds...skies were clear across the
region this morning. Some stratus with IFR to LIFR conds should push
into the Salinas valley before daybreak. Any low ceilings and visibilities
should clear by middle morning.
Expect stratus with IFR conds to affect coastal sections of l.A.
County late tonight/Thursday morning.
Klax...moderate confidence in the taf 12z taf. There is a 30
percent chance that conds will remain VFR tonight/Thursday morning.
Kbur...high confidence in the 12z taf with VFR conds through the period.
Marine...07/835 am PDT
Outer waters...have added Small Craft Advisory for zone 673 and 676
this morning and zone 670 for late this afternoon with all outer
waters experiencing northwest winds 15 to 25 knots with gusts to 30 knots from
Point Sal south to around San Nicolas Island. Winds will become more
widespread across the outer waters by this evening. Theer is a 70
percent chance that small craft advisories will be needed once again
by Thursday afternoon and continuing through at least Friday
night...mainly the western portions.
Two long period southern hemisphere swells will move through the
waters Thursday and Friday...and both will persist into the weekend.
A west-southwest swell will move into the waters Friday night through
Sunday...peaking near 8 feet at 15 seconds over the outer waters.
Inner waters...there will be some local offshore winds remaining
below Small Craft Advisory thresholds between Ventura and Malibu
both Thursday and Friday mornings. 30 percent chance that Small
Craft Advisory will be needed for zone 650 and 655 below the passes
and canyons from Ventura to Malibu. 10 percent chance for the San
Pedro Channel to Catalina Island. Otherwise no issues through the
Small Craft Advisory (see laxmwwlox).