000
FXUS66 KSTO 212148
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
248 PM PDT Sat May 21 2022

.Synopsis...
Periods of breezy north winds and low humidity will bring
elevated fire weather conditions through the middle of next week,
especially Tuesday. Moderate heat risk through the middle of next
week. Dry weather through next week.

&&

.Discussion...
A warming trend remains on track this afternoon with temperatures
running 5 to 12 degrees warmer than yesterday`s readings. Northerly
gradients have relaxed, although some local gusts up to 20 mph
are observed across portions of the northern Sacramento Valley.

Periods of breezy northerly winds remain in the forecast through
mid-week as disturbances pass to the east. Wind gusts from 20-25
mph will be possible through Monday, mainly in the northern
Sacramento Valley and over the mountains. The combination of
breezy northerly winds and very low humidity will likely lead to
elevated fire weather conditions.

Ensembles then show offshore winds strengthening late Monday
night into Tuesday as a shortwave drops into the Great Basin.
Model guidance indicates that the MFR-SAC gradient could peak at
around 10-13 mbs. ECMWF ensemble meteograms show mean gusts from
30-35 mph for some western Valley locations north of I-80, with
some members to around 40 mph. In addition, NBM 4.1 probabilities
show a 50-70% chance of wind gusts exceeding 40 mph across
portions of the western Sacramento Valley. This event is not
expected to be as strong as our last one. However, this could
result in additionally heightened fire weather concerns on
Tuesday.

Ensemble guidance advertises a strengthening ridge this weekend
into mid-week that will promote a warming trend across interior
NorCal. This will bring widespread 90s to the Valley early next
week. By Tuesday, Valley highs will be in the upper 90s to around
100. The heat risk will run in the moderate category across the
Valley through mid-week, impacting groups that are sensitive to
the heat.

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
The heat will continue and peak on Wednesday with Valley
temperatures around 100 degrees. Then, Thursday will see some
relief as a trough deepens and makes its way onshore. Temperatures
are expected to be about 10 degrees cooler Thursday and another 5
degrees on Friday. There is some uncertainty in the clusters on
the timing of the trough, but there is decent confidence that
along with the cooler temperatures, this sytem will bring onshore
flow and higher humidities, bringing some relief to fire weather
concerns. This system could bring light precipitation chances to
far Northern California late week.

&&

.AVIATION...
VFR conditions next 24 hours. Light winds through 10Z Sunday,
then northerly surface wind gusts 15-25 knots over the western
Valley.

&&

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

$$