Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
1030 PM PDT Thu Jul 31 2014
hot temperatures with a cooling trend beginning Sunday. A return
to Sierra showers and thunderstorms possible again early/mid week
A couple of hot days forthcoming...until the ridge axis shifts ewd
over the rockys and onshore flow is sufficiently strong enough to
provide some noticeable cooling. Max temps for the valley are
forecast to surpass 100 degrees but remain short of any records for
Turned out the earthen dam on private property in Yuba co was
inspected and deemed structurally sound. Jhm
Drier air will filter into the area tomorrow (fri) with the
increased southwest flow as weak trough develops over the eastern
Pacific. Isolated thunderstorms will be confined to the Lassen
area...dry over the rest of the Sierra. Temperatures will remain hot
as valley readings rise to from 100-105 degrees.
Slightly cooler Saturday then a few more degrees of cooling Sunday
as Delta breeze/onshore flow develops. Moisture will remain east
of the area keeping thunderstorms over Nevada.
Extended discussion (monday through thursday)
Medium range models showing diverging solutions through the
extended period leading to uncertainties in forecast. Guidance
similar in gradually building upper ridging through the period
but differ with depth and track of offshore upper low. Naefs mean
precipitable water ensembles and GFS/ECMWF-hires relative humidity progs show a
trend upward in moisture through the extended period. GFS elevated
instability also show increasing mid level cape and total totals
over the mountains through midweek. Forecast thus advertising
threat over the higher terrain of the Sierra Nevada, Plumas, and
Shasta mountains Tuesday, expanding over Shasta into the coastal
range Wed into Thu. High temperatures expected to be near to
slightly above normal Mon through Thu.
Swly flow Alf with upr trof ofshr and upr rdg axis ovr grt basin.
VFR conds ovr intr norcal nxt 24 hrs. Isold swly sfc wnd gsts to
arnd 25 kts poss ovr hyr mtn trnn and thru Delta aftns into Eves.