Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
836 am PDT Tue Mar 31 2015
cooler, but still above normal weather expected this week. Weak
weather systems may bring a few showers to the mountains today and
Wednesday. Another chance of precipitation arrives this weekend.
forecast on track so no updates this morning. Current radar has
scattered showers across Humboldt and Trinity counties moving
eastward toward the coastal mountains. Some of those showers could
impact the higher terrain across interior norcal this afternoon,
mainly in Shasta County. Breezy west to northwest winds today as
onshore flow is enhanced with the incoming weak front. Jbb
Previous discussion...high clouds associated with the upper level front are
passing through norcal early this morning. The surface cold front
is presently on the north coast where a few showers are occurring
from Eureka northward to around Crescent City. Onshore flow has
increased across the region with breezy westerly winds in the
Delta and locally across the higher terrain. Temperatures are a
mixed bag early this morning with some areas quite a bit milder
than 24 hours ago due to wind and clouds while others are cooler.
Readings are mainly in the 30s and 40s in the mountains with 50s
to lower 60s in the Central Valley.
The cold front will be mainly dry as it pushes inland across the
interior of norcal today, though a few showers will be possible
across mainly the higher terrain of Shasta County. The main
impacts from the system for the region will be to finally bring a
return of much cooler temperatures - generally 10-15 degrees
cooler today - and breezy northerly winds behind the front.
Another short-wave will move through the area Wednesday
maintaining the cooler temperatures and also spreading a chance of
showers further south into the northern Sierra.
By Thursday and Friday, the trough shifts east into The Rockies
while short-wave ridging moves overhead norcal for a little milder
weather. We'll also see stronger northerly winds developing,
particularly on Thursday when advisory level criteria may be
Extended discussion (saturday through tuesday)
A trough of low pressure will settle over the region this weekend.
The Canadian model is more bullish with the precipitation while
the GFS has the trough tracking farther to the north. The latest
European model is starting to look more like the GFS but is deeper
on Sunday and Sunday night with the precipitation over the region.
Timing differences and differences in the strength of the systems
exist with all the models so for now have slight chance to chance
pops over most locations Saturday through Tuesday. Temperatures
will be cooler during this period with the potential for some snow
below major trans-Sierra pass levels.
VFR conditions will continue the next 24 hours. Next system may bring
light showers to northern mtns late today. Gusty winds through
the Delta and over the mountains with gusts around 25 kts in the
Delta and 40 kts over ridges through tonight before dying
down to around 10 kts overnight.