FXUS66 KSTO 262032
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
132 PM PDT Mon Aug 26 2024

.SYNOPSIS...
Warmer and drier conditions this week with cooler temperatures
later this weekend, and periods of breezy winds.

&&

.Discussion...
Current GOES-West visible satellite imagery illustrates clear
skies and abundant sunshine being observed across interior
northern California early on this Monday afternoon. Temperature
observations are currently trending approximately 5 to 10 degrees
warmer than this time yesterday afternoon, in the 80s to low 90s
in the Valley and lower foothills, and 60s to 80s in the upper
foothills and mountains, valid at 130 PM PDT.

A gradual warming trend is expected over the next few days as
upper level ridging acts as the main influence with a trough
briefly passing by to the north Tuesday into early Wednesday.
High temperatures are generally forecast to be in the 90s to
around 100 degrees in the Valley with 80s to 90s in the foothills
and 70s to 80s in the mountains over the short term. Minor HeatRisk
with areas of Moderate HeatRisk expected over the next few days.
Dry conditions will persist each day, with daytime relative
humidity around 10 to 25 percent, lowest in the northern
Sacramento Valley. Warmest and driest conditions peak
mid-week before cooling temperatures and increasing humidity
return for the extended forecast period.

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)...
Ensemble guidance and cluster analysis indicate upper level
troughing over the extended forecast period bringing a cooling
trend to the forecast area, along with increased onshore flow.
High temperatures are currently expected to generally be in the
80s to 90s for the Valley and foothills, with upper 60s to 80s for
the mountains over this timeframe, and mainly Minor HeatRisk.
Relative humidity is also expected to trend higher, with the
assistance of onshore flow. Periods of breezy conditions can also
be expected, especially through the Delta and vicinity where there
is a light signature on the Extreme Forecast Index (EFI). There
is some uncertainty in exact details but the National Blend of
Models (NBM) is also suggesting around a 5-15% probability of
isolated thunderstorms over the Sierra Nevada Crest this weekend,
however this has trended lower since previous forecasts. Stay
tuned for more details on the holiday weekend as we get closer!

&&

.AVIATION...
VFR conditions with a few high clouds over interior NorCal next
24 hrs. Sfc wind below 12 kts except vcnty of Delta SWly sfc wind
up to 15 kts possible btwn 00z-14z Tue.

&&

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

&&

$$