FXUS66 KSTO 222134
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
234 PM PDT Sun May 22 2022
Synopsis...
Periods of breezy north winds and low humidity will bring
critical fire weather conditions through mid-week, especially
Monday and Tuesday. Moderate heat risk through the middle of this
week, with temperatures peaking Wednesday. Cooler temperatures and
onshore winds expected late week as a system passes to the north.
.Discussion...
Locally breezy northerly winds up to 20-25 mph are being observed
across portions of the Sacramento Valley this afternoon as a
shortwave moves into the Great Basin. With humidity values from the
single digits to the teens across the Valley this afternoon,
elevated fire weather conditions continue.
Ensembles show offshore winds strengthening Monday into Tuesday
as another system drops into the Great Basin. This wind event is
not expected to be as strong as our last one. However, the
combination of breezy northerly winds and very low humidity will
likely lead to critical fire weather conditions. The MFR-SAC
gradient could peak at around 10-13 mbs; strongest winds from
early Tuesday morning into Tuesday afternoon. This may lead to
northerly gusts up to 35 mph in portions of the Valley and Coastal
Range foothills. Daytime humidity values will remain low in the
single digits to teens. Therefore, a Red Flag Warning has been
issued for Monday and Tuesday. Lighter winds are expected on
Wednesday, becoming onshore Wednesday evening.
Ensemble guidance advertises a strengthening ridge that will
continue to promote hot temperatures across interior NorCal
through mid-week. Valley temperatures may reach into the triple
digits both Tuesday and Wednesday, with the hottest temperatures
on Wednesday as ridging moves overhead. Overnight lows Tuesday
into Wednesday may only cool into the upper 60s to mid 70s.
The heat risk will run in the moderate category across the Valley
through mid-week with some locally high heat risk. Therefore, a
Heat Advisory has been issued for the Valley from Tuesday
afternoon through Wednesday evening. Take precautions to prevent
heat-related illnesses. In addition, some Valley locations could
tie or break their high temperature records for both Tuesday and
Wednesday. Here are some record temperatures for Tuesday and
Wednesday:
Tue (May 24) Wed (May 25)
Redding..........102 (1982) 103 (1982)
Red Bluff........105 (1943) 105 (1982)
Downtown Sac.....100 (2001) 100 (2020 & 1951)
Sac Exec.........100 (1982) 100 (1951)
Stockton.........104 (1982) 102 (1979)
.EXTENDED DISCUSSION
(Thursday THROUGH Sunday)
...
Slightly better agreement in clusters for the timing of a trough
developing offshore on Thursday. This will bring cooler
temperatures, onshore flow, and higher humidity to the area on
Thursday continuing into late Friday. Thursday temperatures will
be roughly 8-12 degrees cooler than those hot temperatures
expected the day before, with a few more degrees of cooling
expected on Friday. A few showers are possible with this passing
system, mainly in far northern California. This system continues
east with EPAC high pressure building just offshore through the
weekend.
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