Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 291019
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
319 AM PDT Fri May 29 2015

.Synopsis...
Well above normal daytime temperatures today and Saturday as high
pressure slides across the west coast. Cooler early next week with
a slight chance of showers and thunderstorms over the northern
Sacramento valley and surrounding mountains as the tail end of a
Pacific trough brushes through. Warmer by mid week.

&&

.Discussion...
High pressure ridging over the west coast bringing mainly fair
skies to northern California this morning. Coastal stratus making
its way through the delta again with similar delta breeze and
marine layer conditions to early Thursday. Therefore expect some
brief patchy stratus to make it into the southern Sacramento
valley later this morning. Otherwise...another quiet day expected
with subsidence under the ridge likely to prevent any afternoon
mountain thunderstorm threat. Overall airmass warms slightly for a
slight warm up today. Maximum temperatures today will be pushing
up close to the warmest of the season so far most areas. Upper
ridge axis shifts inland over the Great Basin on Saturday for a
slight cooling. Slightly deeper marine layer and slightly stronger
onshore flow so would expect a little patchy coastal stratus in
the valley again Saturday morning. Otherwise...generally fair
skies are expected for the first half of the weekend. The upper
Pacific low pressure system now centered around 39 north 151 west
is forecast to approach the coast on Sunday. Main impacts Sunday
will be increasing winds especially over higher terrain and a drop
in daytime temperatures. If current timing holds...the coastal
range could see a few showers or isolated thunderstorms in the
late afternoon and evening hours. The system then lifts to the
northeast on Monday on its way to the Pacific Northwest. A much
more significant cool off will occur on Monday with daytime highs
forecast to drop to a few degrees below normal. The northern
portions of the CWA will see a chance of showers but stability
progs are not showing enough instability to indicate
thunderstorms. Current models fairly consistent in keeping
precipitation threat north of about Red Bluff with southern areas
remaining dry.


.Extended Discussion (Tuesday through Friday)

Weak upper trough moves through Tuesday followed by weak upper
ridging Wednesday, then another weaker trough Thursday into Friday.
Slight chance of showers are possible over the Shasta and Plumas
mountains Tuesday, otherwise dry weather expected. High temperatures
forecast to gradually trend upward through the extended forecast
period.


&&

.Aviation...

Upr rdg ovr the fcst area nxt 24 hrs. Mnly VFR conds for Intr
NorCal exc isold MVFR/IFR cigs poss in Delta and Srn Sac Vly in
ST til arnd 17z Fri. Lcl SWly sfc wnd gsts to arnd 25 kts thru
Delta til arnd 16z Fri.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$







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