Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 172039
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
139 PM PDT Sat Jun 17 2017

.Synopsis...
An extended heat wave continues this weekend through most of next
week with widespread highs over 100 degrees and warm nights.
Isolated afternoon thunderstorms possible near the Sierra Crest
from around Lake Tahoe and southward for Sunday and Tuesday,
spreading into the northern mountains for Monday.

&&

.Discussion...
Hot weather continues to be the main weather story this weekend
and next week. Northerly winds will continue this weekend before
reversing direction by Monday morning. The winds tonight will help
to keep temperatures very warm overnight well into the 70s for
overnight lows in the valley. This will likely be the warmest
night for many valley locations. Winds overnight will also help to
increase the fire danger for parts of the Sacramento Valley and
Southern Lake County into Sunday evening. Some help from the Delta
may occur Monday night and Tuesday night but with the hot airmass
over the west we will likely still be over 100 degrees for
Tuesday and Wednesday in Sacramento and close to 105 for the
daytime highs.

Some record highs are listed below.
Record Highs...........Today......Sunday.....Monday.....Tuesday
Redding Apt............104(2012)..102(1988)..104(1988)..107(2001)
Red Bluff..............109(1982)..109(1959)..110(1970)..110(1970)
Sacramento.............102(1976)..105(1945)..106(1988)..108(1920)
Sacramento Exec........103(1963)..102(1988)..105(1988)..109(1961)
Stockton...............103(1963)..104(1981)..108(1981)..107(1981)
Modesto................103(2012)..104(1981)..105(1981)..106(2008)

There is a weak shortwave that will approach the region on Monday
then move through the region Tuesday and Wednesday.
Models are hinting at some thunderstorm potential over the
northern mountains and along the crest...mainly crest and to the
east for Monday. GFS is more bullish indicating some of the convection
that starts Sunday from around Tahoe southward spreading over the
northern mountains and persisting through late Monday night. For
now have kept afternoon and evening mention of thunderstorms but
it`s something that we will need to keep an eye on.

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)

Triple digit highs are going to continue into the start of the extended
forecast for the valley as a ridge remains in place. An upper
level low will start to dig south into the Pac Northwest on Friday
and that will help to flatten the ridge and bring falling heights
for us. This will bring cooler high temperatures starting Friday
but still could see some 100`s. Things look a bit cooler into next
weekend with 90`s in the valley. Overnight lows will also return
closer to average starting Friday night and that will bring some
relief from the heat for the overnights. Breezy northerly winds
will be possible for the valley both Thursday and Friday
afternoon.

-CJM
&&

.AVIATION...


VFR conditions expected the next 24 hour for the TAF sites.
Winds will be northerly 10-15 knots gusting 20-25 knots at times
across the valley.

-CJM
&&

.STO WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon Sunday to 8 PM PDT Wednesday for
Carquinez Strait and Delta-Central Sacramento Valley-Clear
Lake/Southern Lake County-Motherlode-Mountains Southwestern
Shasta County to Northern Lake County-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Shasta Lake Area / Northern Shasta County-
Southern Sacramento Valley-West Slope Northern Sierra Nevada-
Western Plumas County/Lassen Park.

Red Flag Warning from 11 PM this evening to 9 PM PDT Sunday for
Central Sacramento Valley in Glenn, Colusa, Yuba, Northern
Sutter, and Butte County Below 1000 Ft-Lake County Portion of
Lake-Napa-Sonoma Unit-Northern Sacramento Valley to Southern
Tehama County Line Below 1000 Ft-Southern Sacramento Valley in
Yolo-Sacramento Far Western Placer, southern Sutter and Solano
County Below 1000 Ft.

Excessive Heat Warning from noon Sunday to 8 PM PDT Wednesday
for Carquinez Strait and Delta-Central Sacramento Valley-
Northern Sacramento Valley-Northern San Joaquin Valley-Southern
Sacramento Valley.

&&

$$



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