FXUS66 KSTO 190915
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
215 AM PDT Fri Jul 19 2024

.SYNOPSIS...
Hot weather persists into next week. Thunderstorm chances along
and east of the Sierra/Cascade crest into next week as well.

&&

.Discussion...
Skies are clear other than some mid and high clouds continuing to
spread northward over the Sierra from central California. The
warming trend continues as onshore gradients slacken and the
marine layer becomes more shallow (< 1k ft deep). Current
temperatures are mostly running around 5-10 degrees milder
compared to 24 hours ago.

The hot weather pattern will continue into next week as the strong
upper ridge remains in place centered to our east over the Great
Basin. With the high center in this position, it is not expected
to be as hot as last week and a weak Delta Breeze will bring some
local cooling into the southern Sacramento Valley each night.
HeatRisk is forecast to remain mostly in the Moderate category,
though some areas of Major HeatRisk will be possible early next
week.

Another short-wave trough is forecast to lift northward off the
coast and toward the PacNW over the weekend. This will result in a
reinvigorated Delta Breeze bringing moderate relief for a couple
days to the Delta and southern half of the Sacramento Valley.
Areas further inland will remain hot with little relief from the
heat. In addition to bringing some cooling, this system will draw
moisture/instability further north as it approaches and late-day
thunderstorm chances will likely spread up into the northern
mountains over the weekend. A greater risk of more widespread
thunderstorms will occur to the north of the region.

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
Desert SW upper high extends over interior NorCal early next week
week resulting in high temperatures upwards of 10 degrees above
normal. Triple digit heat expected throughout the Central Valley
Tuesday with highs 100 to 110, hottest in the N Sac Valley.
Widespread moderate to major heat risk expected with local areas
of extreme heat risk. Upper high gradually weakens through the
week and is replaced with upper troughing resulting in a gradual
downward trend in high temperatures. By Friday, NBM forecasting
high temperatures near to slightly above normal. Monsoonal
moisture advecting around periphery of upper high could provide
potential for thunderstorms, mainly during the afternoons, over
higher elevations of the Sierra Nevada Tuesday into Thursday.

&&

.AVIATION...
VFR conditions over interior NorCal next 24 hrs. Sfc wind mainly
below 12 kts except vcnty of Delta SWly sfc wind up to 20 kts
possible aft 00z Sat.

&&

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

&&

$$