Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
402 am PDT Wednesday Jun 3 2015
isolated shower and thunderstorm chances will persist
today over the northern mountains. Another low pressure system will
affect the region through the remainder of the week bringing an
increase in clouds and mainly mountain showers and thunderstorms.
clouds moving across norcal overnight ahead of short-
wave trough presently moving onto the coast. This is helping to keep
temperatures rather mild across the region early this morning with
current readings in the 40s and 50s in the mountains and upper 50s
and 60s in the Central Valley.
Conditions today are expected to be pretty similar to tuesday's
across the region. An isolated late day shower or thunderstorm may
develop over the northern mountains, but the remainder of the region
will remain dry with warm temperatures.
The next upstream wave is presently approaching 130w and is forecast
to move into norcal tonight, then close-off over central California
on Thursday as it moves south. This system will bring another
upswing in mainly mountain shower and thunderstorm activity that
will persist into the weekend. Temperatures will remain warm.
Extended discussion (sunday through wednesday)...
the closed low
that dropped over central/Southern California is now expected to slowly
weaken and elongate across Nevada and extend back across California.
The wraparound east to northeast upper flow will still bring the
threat of convection through Monday. The highest chances of
convection look to be across the mountains, but portions of the
valley look to be in play. A secondary low then develops off the
central/Southern California coast that will keep the convective
threat in place over mountains at this point. Trajectories of these
types to cutoff lows are difficult, so stay tuned. Temperatures will
cool a few degrees over the weekend and hinge on resulting cloud and
precipitation coverage, but will generally be close to normal. Temperatures
increase slightly next week, but that depends on what the upper low
decides to do. Jclapp
VFR conditions expected for most of the period. 60%
chance of MVFR ceilings forming over southern SAC valley (mainly
ksac/kmhr)this morning between 13-16z. Generally light winds with
onshore flow...up to 12 kts. Jclapp