Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 270348
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
848 PM PDT Wed Jul 26 2017

.SYNOPSIS...
Hot weather returns Thursday into early next week. A slight
chance of afternoon mountain thunderstorms over the weekend.

&&

.DISCUSSION...
Low pressure area over northeast part of the state will move
to the northeast overnight and into Thursday. Isolated activity
north and northeast of the forecast area will continue to
dissipate this evening.

Temperatures trending warmer this evening with the exception of
the north end of the valley which is slightly cooler than 24
hours ago as of 8 PM. Winds through the Delta will be slightly
weaker tonight and stratus has been remaining along the coast this
evening. Temperatures will continue to cool off into the upper
50s to upper 60s in the valley overnight with the mountain
valley`s cooling off into the 40s and 50s.

Temperatures will continue to warm slightly on Thursday over
today`s highs. Thursday may be the warmest day of the next few for
the Sacramento region but further inland temperatures look like
they will remain hot. NAM model is indicating an eddy forming
along the coast on Friday and persisting on Saturday that may
have an impact on temperatures for the Sacramento region.

.PREVIOUS DISCUSSION...
Closed upper low moved onshore overnight and is currently centered
across the northern Sac Valley. Cool start to the morning quickly
gave way to the beginning of a warming trend today as drier air
moves in. Temperatures running several degrees warmer than 24
hours ago with afternoon highs expected in the upper 90s to around
102 degrees in the Valley. Like the past few days,convection
developing to the north and east of the area with only a few
shallow returns over Shasta and Tehama County. Not expecting
widespread activity with perhaps only a few lightning strikes.

Low will weaken and slowly meander east over the next several
days as high pressure over the desert southwest expands toward the
area. Temperatures will continue to warm into the weekend with
widespread triple digits in the Valley, hottest across northern
Sac Valley. 80s-90s across the foothills and mountains. For now,
looks like some relief at night with overnight lows in the mid
60s-low 70s across the Valley. Those who are sensitive to heat
should take extra precautions! Another monsoon moisture surge
possible by the weekend, though models have backed off slightly on
this over the past few runs. Small chance for a thunderstorm or
two near the Sierra crest, mainly south of Tahoe on Saturday.

CEO

&&
.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)

12z ECMWF-HiRes showing better agreement with last several oper
GFS-20 runs. Strong upper high pressure forecast over Interior
NorCal Sunday with triple digit heat continuing in the Central
Valley. Highs forecast to be around 10 degrees above normal but
below record values. Little change in heights/thicknesses Monday
as upper high center shifts into Western Nevada. Some moisture may
be drawn over the higher terrain of the Sierra Nevada Monday
leading to possible isolated afternoon thunderstorms near the
crest. Weak upper low progged across northern portions of CA
Tuesday which may result in minor height falls over CWA then
heights rebound back Wednesday. As a result, minor fluctuations in
high temperatures expected through midweek. Flow around
quasistationary upper high over NV will keep a threat of afternoon
thunderstorms over higher terrain of the Sierra Nevada into
Wednesday.


&&

.AVIATION...

Upr low ovr Intr NorCal movs E tngt aft 06z. VFR conds ovr fcst
area nxt 24 hrs exc lcl MVFR/IFR poss in ST vcnty of Delta btwn
08z-17z Thu. Isold mtn tstms poss thru 04z Thu. Lcl SWly sfc wnd
gsts to 25 kts ovr hyr trrn til 04z Thu and thru Delta til arnd
12z Thu.
&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$



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