134
FXUS66 KSTO 262128
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
228 PM PDT Sun May 26 2024

.SYNOPSIS...
A warming trend continues this week, with generally above normal
temperatures. Minor HeatRisk is expected early in the week, with
the moderate through the week ahead. Weak onshore flow also
persists through Tuesday, before dry, northerly flow arrives from
Wednesday through the end of the week. Elevated fire weather
concerns for the northern and central Sacramento Valley Thursday.

&&

.DISCUSSION...
Upper level ridging with mostly clear skies has brought warmer
temperatures for today, with 2 pm temperatures 5 to 15 degrees
higher than the same time on Saturday. Valley highs in the mid to
upper 80s are on track.

Broad troughing aloft will continue to influence interior NorCal
as another trough from the Gulf of Alaska moves eastward toward
the Pacific Northwest early this week. A few isolated, late day
showers will be possible along the Sierra crest on Monday,
generally south of the Highway 50 corridor. Generally this
pattern will lead to warming temperatures into week, with
afternoon high temperatures rising into in the mid 80s to low
90s. This pattern will also allow south to west winds to
continue, bringing Delta breezes with some cooling in the evening
and at night for influenced areas.

Ensemble guidance continues to show the trough exiting eastward
from the Pacific Northwest mid to late week. This track will
increase northerly winds, especially over the northern and central
Sacramento Valley. There is a 45-55% probability of wind gusts
greater than 40 mph in those areas. The gusty winds with low
humidity will bring elevated fire weather concerns there and for
the adjacent foothills. Fine fuels are not completely cured,
though, which is a mitigating factor. Onshore, westerly flow
persists further southward, generally from I-80 to the south, with
higher humidity recovery at night. Temperatures overall still
look to remain slightly above normal, with Valley high
temperatures in the mid 80s to low 90s, and 70s to 80s at higher
elevations, today through Thursday. Minor HeatRisk is expected to
accompany these temperatures through Wednesday, with areas of
Moderate HeatRisk for the central and southern Sacramento Valley
on Thursday as temperatures rise a little higher.

&&

.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...
While upper level troughing will have kept the area from getting
to far above normal temperatures early in the week, by Thursday
the dominant pattern becomes transient ridging. The transition
from troughing to ridging will bring breezy winds on Thursday,
along with the potential for strong gusts. NBM currently has the
potential for 30 mph gusts or stronger in the northern Sacramento
Valley sitting around 35 to 80% probability, with highest chances
along the I-5 corridor in the northern Sacramento Valley.
Probabilities for 40 mph gusts or stronger are more localized
between Red Bluff and Dunnigan along the I-5 corridor, but are
still around 30 to 55% in that area. These winds will also likely
bring low relative humidities to the Valley, as low as the low to
mid teens, though primarily this will be in the northern
Sacramento Valley. The entrance of the ridging pattern will also
increase temperatures to above normal in the late week and into
the early weekend, with highs in the 90s in the Valley, 80s in the
foothills, and 70s in the mountains. The ridging will be
interrupted by shortwave troughing late in the weekend however,
bringing temperatures back closer to normal. //SP &&

.AVIATION...
VFR conditions next 24 hours, except for local southwest wind
gusts to 20 kts near the Delta.

&&

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

$$