Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 300453
Area Forecast Discussion
National Weather Service Sacramento CA
950 PM PDT WED JUN 29 2016
Hot and mainly dry weather this week. Isolated late day
thunderstorms possible over the mountains.
Most locales were cooler on Wed except in Shasta Co...with the Delta
influenced region some 7 to 13 degrees cooler. Onshore pressure
gradients increased to over 5 mbs and the marine layer deepened from
around 800 ft to nearly 1800 ft as a weak upper level trof moved
onshore initiating a cooling trend primarily felt in the Valley with
minor cooling in the mtns.
A baggy trof is forecast to remain over Norcal on Thu but the Delta
Breeze should weaken during the day. This will lead to warming
during the day after a refreshing start to the day in the Valley
unlike the last couple of mornings. With the presence of some marine
air in the Valley...we would not anticipate a full recovery of max
temps...and would expect more of a moderate warm-up than our current
max temps grids show. We will be working on this for the morning
forecast with our initial thinking that max temps may trend closer
to the 30/00z ADJMET grids as we refrain from using the BC grids.
Advection of stratus is likely inland...but not necessarily at the
inland airports. The air mass is dry and should erode the stratus as
it moves inland. However...if the Breeze continues overnite...we
could experience some stratus on the E side of the Srn Sac Vly. JHM
High pressure continues to be the predominant weather pattern across
interior northern California. Temperatures, as of this afternoon,
are running a few degrees cooler compared to 24 hours ago. Delta
breeze should bring some cooling overnight, with lows in the mid 50s
in the Delta, and upper 50s to low 60s near the Sacramento area.
Light easterly flow overnight may drift smoke from the Trailhead
fire down into the Auburn area.
Cooling trend is expected late this week, as an upper trough
develops along the Pacific Northwest. Saturday`s highs should be
around the mid 90s in the Valley, except for a few triple digits
in the northern Sacramento Valley. Model guidance suggest
monsoonal moisture making its way northward along the Sierra crest
late this week. Isolated storms may be possible mainly south of
Lake Tahoe and east of the Sierra crest. A few late day afternoon
thunderstorms may be possible along the Coastal Range late this
week, as some instability might be present.
.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
A weak upper trough will persist over the Pacific Northwest over
the weekend into early next week with subtle cyclonic flow over
NorCal, resulting in dry weather and near normal temperatures.
Expect high temperatures in the 90s across the Valley, with 70s
and 80s over the mountains.
VFR conditions the next 24 hours. Light winds generally below 10
kts, except occasional SW wind gusts 30 kts through the Carquinez