Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 240411
Area Forecast Discussion
National Weather Service Sacramento CA
911 PM PDT MON MAY 23 2016
An upper level disturbance will continue to bring unsettled
weather and cool conditions across NorCal most of this week.
Warmer and mainly dry conditions by this weekend.
Low pressure area is moving over the Northern San Joaquin Valley
this evening. Showers have been gradually dissipating this evening
over the interior. The HRRR model is indicating some showers
enhancing over Shasta County and moving over the north end of the
valley overnight while the NAM model is keeping the valley dry and
indicating just a few showers over the mountains.
That shortwave over the San Joaquin Valley on Tuesday will help to
continue unsettled weather for the region. Most of the activity
will be focused over the mountains but some showers or isolated
thunderstorms could end up over the valley once again. Isolated
thunderstorms will continue to be possible for the afternoon into
the early evening hours.
On Wednesday the low moves over Southern California. This will
keep unstable conditions over the region with most of the activity
continuing to be focused over the mountains and slight chances
over the northern half of the Sacramento valley. Temperatures will
continue to be cooler than normal but 3-5 degrees warmer than
On Thursday the trough moves far enough to the east to dry out
most areas. Only some isolated afternoon showers over the
mountains near the crest look possible. Temperatures will warm
back up to near seasonal normals.
.EXTENDED DISCUSSION (Friday THROUGH Monday)
On Friday, Northern California will be on the relatively dry
backside of the upper level trough. The northernly flow should
bring dry conditions to nearly everyone although there could be
enough instability in the Sierra to set off some afternoon
thunderstorms. For both Friday and Saturday, winds could become a
bit breezy at times while temperatures should be right around
normal for this time of year. Beyond this, both the GFS and ECMWF
have a weak shortwave dropping down the backside of the trough
which may trigger more mountain thunderstorms Sunday and into
VFR conditions expected over the next 24 hours with relatively
light winds. The upper level trough continues to linger over
Northern California and will result in SCT 5-8 kft cumulus in the
valley in addition to a higher (20 kft) SCT to BKN deck. Lcl MVFR
conditions in the mountains. Most of the shower activity tonight
should remain in the higher elevations.