664
FXUS66 KSTO 071044
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
344 AM PDT Fri Jun 7 2024

.SYNOPSIS...
Above normal temperatures persist through the weekend with a
gradual cooling trend. There is another warmup expected early
next week with hot weather for the northern and central
Sacramento Valley.

&&

.DISCUSSION...

Key Points

- Areas of Moderate HeatRisk for today; Triple digits in the
  Northern and Central Sacramento Valley and adjacent Valley
  foothills, less hot in the Delta and Sacramento metro area with
  highs in the 80s to lower 90s.
- Less hot this weekend, through with some areas of Moderate
  HeatRisk, mainly over the northern and central Sacramento
  Valley.
- Another warm up is expected early next week with well above
  normal temperatures returning. Moderate HeatRisk returns to
  much of the Valley and foothills on these days, with areas of
  Major HeatRisk in the northern and central Sacramento Valley.

Short-Term Discussion (Today THROUGH Monday)...

Temperatures at 3 am show significant cooling over the Delta and much
of the Valley, such as Sacramento International Airport at 65
degrees, 13 degrees cooler than this time yesterday. Downtown
Sacramento was also 65, 11 degree cooler, while Vacaville at 64
is 11 degrees cooler. Chico was 73, 8 degrees cooler. This is due
to onshore flow with cooler marine air, the Delta Breeze. Valley
locations which haven`t seen this effect include Redding (77) and
Red Bluff (75), both unchanged from this time yesterday.
Temperatures also remain quite warm in the foothills and
mountains.

Skies are clear today and will remain this way, except for some
cumulus buildups over the mountains this afternoon, especially
over the mountains of western Shasta County. Expecting another day
of dry weather, with convection remaining further to the north and
west, though can`t completely rule out some sprinkles extending
into those areas.

Upper level ridging continues to shift eastward, with west
southwesterly flow bringing a widespread gradual cool down from
today into the weekend. High temperatures cool to simply above
normal with moderate HeatRisk in the Valley and foothills for
today. Valley high temperatures look to top out in the low 90s to
triple digits this afternoon, highest over the northern
Sacramento Valley, with 80s to low 90s still at higher elevations.
Temperatures drop 5 to 10 degrees cooler over the weekend, with
near to slightly above normal temperatures and primarily minor
HeatRisk.

As the flow pattern shifts to onshore flow, winds look to become
diurnally breezy to gusty, with gusts of 20 to 25 mph in the
afternoon and evening hours, primarily across the Delta and into
portions of the southern Sacramento and northern San Joaquin
valleys. A weak trough is expected to travel through the flow
pattern Saturday into Sunday. This may provide enough lift for
some isolated convection on and east of the Sierra crest and
over the southern Cascades (currently 10-15% probabilities), but
the potential for precipitation within the forecast area looks low
at this point.

To view the latest HeatRisk, please visit
www.wpc.ncep.noaa.gov/heatrisk/

To view current water temperatures, please visit
www.cnrfc.noaa.gov

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...

Ensemble clusters continue to be in good agreement that a quieter
weather week is in store as ridging moves through the Pacific
NW/Northern CA with troughing over SoCal. By midweek, a closed
low is projected to be over SoCal with troughing moving through
the Pacific NW. This will allow for several days of the Delta
Breeze helping to marginally cool portions of the Valley. Moderate
Heat Risk is expected in the Sacramento Valley, though, with
areas of Major Heat Risk across the northern Sacramento Valley and
northeastern foothills. Tuesday is forecast to be the warmest day
of the week with highs near or above triple digits across much of
the Valley. NBM probabilities indicate a 40-90% chance of
exceeding 100 degrees on Tuesday, with highest chances along the
foothills and for the Northern Sacramento Valley.

&&

.AVIATION...

VFR conditions prevail over interior NorCal through the forecast
period. Breezy south-southwest winds through the Sacramento
Valley and northwest winds through the San Joaquin Valley thru 09z
Sat. Gusts up to 15-25 MPH across the Delta (thru 12z Sat) and
the Valley (thru 06z Sat).


&&

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

$$