Scientific Forecaster Discussion
Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
340 am PST Thursday Dec 12 2013
Offshore winds will keep this afternoons temperatures around
normal. A weak low will cross the region on Friday to lower the
afternoon temperatures. On Saturday...an upper high and offshore
winds will create a warming trend with above normal temperatures
forecast through Tuesday. Low pressure will arrive by midweek with
more clouds and a cooling trend.
Short term (today-sat)...
the synoptic pattern changes quickly over the next three days. A
weak upper low will pass to the south today...a Little Ridge will
pop over the state Friday only to be displaced by a fast moving
inside slider Saturday.
Today will be much like yesterday with offshore flow dominating the
weather story. L.A. County will start off partly cloudy as some middle
level clouds associated with the upper low shoot overhead. The
clouds should add some color to the sunrise but will dissipate by
noon. Maximum temperatures will be similar to ydys... 2 to 3 degrees above
normal across the csts and valleys and right around normal inland. Some
15 to 25 miles per hour breezes in the usual areas this morning and some patchy
freezing temperatures in the wind sheltered areas as well.
The Little Ridge major effect will be a very sudden reversal of the
offshore flow to onshore. A weak eddy will also spin up and it looks
like the Long Beach to Santa Monica area will see some patchy marine
layer clouds. Inland temperatures will stay the same but the coasts and
valleys will see a noticeable drop in temperatures from the switch to onshore
But just as soon as the onshore flow arrived it will depart as an
inside slider moves down the California/Nevada border. North winds will develop
Friday night and then switch to the northeast Saturday morning.
Right now it looks like there will be a need for some low end wind
advisories. Fire danger will Jump Up as well. Maximum temperatures will rebound
with the offshore flow as well.
Long term (sun-wed)...
three very nice days are on tap sun through Tuesday as a ridge builds into
the state from the east Pacific. Continuous offshore flow and 586 dm
heights (about 15 dm greater than normal) will pump maximum temperatures into the
lower 80s for Monday and Tuesday for quite a few locations across the
coasts and valleys. Overnight lows will plummet each night in the wind
sheltered area as the very long nights and very dry air combine to
allow maximum radiational cooling.
The ridge breaks down Wednesday and some upper level clouds may
drift overhead. Maximum temperatures will likely cool...especially at the coast.
Hi confidence in the 12z taf package with VFR conditions expected at
all airfields through at least 08z Thursday then a 60 percent chance of IFR
ceilings from klgb to ksmo.
Klax...hi confidence in the 12z taf through 08z then a 40 percent
chance of no ceilings.
Kbur...hi confidence in the 12z taf.