A strong ridge of high pressure expanded westward over California, bringing unseasonably hot temperatures to interior areas. Temperatures peaked in the 100s up to 110 deg on August 16.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MTR wrote it up.
A strong ridge of high pressure expanded westward over California, bringing unseasonably hot temperatures to interior areas. Temperatures peaked in the 100s up to 110 deg on August 16. A heat advisory was issued for the late morning through evening hours covering all interior mountain zones, the southern Salinas Valley, and the East Bay interior valleys.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Francisco Bay Area, CA wrote its last area forecast discussion before the first event at Aug 16, 1:52 PM PST, 1 hour 8 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
252 PM PDT Tue Aug 16 2022
...Significant Heat for Interior Areas this Afternoon...
...Isolated Thunderstorms Possible Late Tonight Into Wednesday
Morning...
.SYNOPSIS...Temperatures will peak this Tuesday afternoon with
triple digit values across interior areas of the Bay Area and
Central Coast. Gradual cooling is expected through the remainder
of the week with temperatures returning to near seasonal averages
by the weekend. Upper level moisture will move over the region
tonight and early Wednesday providing a slight chance for showers
and thunderstorms.
&&
.DISCUSSION...as of 02:40 PM PDT Tuesday...The heat is on, well
at least away from the immediate coast. The much advertised heat
has arrived for the Bay Area and Central Coast. First and
foremost, the Heat Advisory for interior portions of the Bay Area
and Central Coast remains in effect through 8 PM this evening. The
warming trend noted this morning continued this afternoon.
Generally speaking many locations are running 2-12 degrees warmer
than yesterday at this time. At the immediate coast (and SF) is a
different story where much cooler weather is being observed. In
fact, we're seeing almost a 50 degree temperature spread from the
coast to interior portions of the forecast area. Pinnacles has
reached 106 degrees as of 2 PM. Needless to say there is elevated
Heat Risk concerns today due to the heat. If you have outdoor
activities planned this afternoon plan accordingly and use
caution. Lastly, never leave people or pets in vehicles. For
tonight, some low clouds along the coast this afternoon will move
locally inland, but will remain shallow. Even with some low
clouds, not expecting much in the way of widespread relief with
overnight lows remaining relatively mild. In fact, higher
elevations will remain in the 60s/70s with a few isolated spots
near 80 degrees.
High pressure that brought the dangerous heat will begin to ease
tonight and more so later in the week. A gradual step down of
temperatures will occur over the next few days. In stead of triple
digit heat across the interior temperatures will return to more
seasonal levels and in the 90s to near 100. Closer to the coast
will also cool as onshore flow increases.
The more notable update with the afternoon forecast was the
introduction of showers and thunderstorms tonight and early
Wednesday. Previous forecast had referenced a non-zero chance for
thunderstorms, but today's model guidance has changed that
thinking. A very weak vort max off the SoCal coast is forecast to
link up with an upper level jet and strengthen as it moves toward
the Central Coast tonight. By early Wednesday morning the vort
max becomes a pronounced shortwave trough with a negative tilt.
As this happens, flow aloft shifts to more SE. This SE flow will
usher in upper level moisture. The increase in upper level
moisture will coincide with the developing shortwave setting the
stage for showers and thunderstorms. A look at a few convective
parameters show: MUCAPE > 200 j/kg, steep mid-level lapse rate,
and Modified Total Totals >32. CAMs models also show higher
forecast reflectivity and increased lighting flash rates.
Therefore, have included showers and thunderstorms beginning as
early as 06Z tonight and continue through Wednesday afternoon.
Taking a look at sounding profiles also shows the sub-cloud layer
to be rather dry so dry thunderstorms/lightning is not out of the
question. After coordinating with neighboring offices and agency
partners will not issue a Red Flag Warning. Confidence is just not
high enough. That being said, will be monitoring this situation
closely this evening and overnight. Finally, despite today being
the anniversary of the 2020 Lightning Outbreak tonight's lightning
set up is not the same as that historic event.
&&
.AVIATION... As of 10:30 AM Tuesday... For the 18Z TAFs. Low fog has
lifted in much of the Monterey Bay and Salinas Valley with IFR-LIFR
ceilings persisting at the immediate coast but VFR conditions at SNS
and WVI. Smoke from the fires farther north is also impacting the
North Bay with potential for reductions in slant visibility.
Elsewhere mostly VFR with LIFR stratus at the immediate coast. Winds
are breezy but not as strong as seen a couple of days ago with most
terminals seeing winds top out at 10-15 knots from the west.
Overnight stratus coverage should be limited to the immediate coast
in the San Francisco Bay area, with perhaps a few wisps of stratus
leaking through the Golden Gate. Further south, stratus coverage
should be extensive in Monterey Bay. Clearing time expected around
16z. Also monitoring potential for scattered showers and
thunderstorms overnight into tomorrow, although with low confidence
in general location.
Vicinity of KSFO... VFR for the TAF period. Rather breezy winds with
gusts approaching 20 knots from the west this afternoon, with little
chance of stratus coverage overnight. Winds on Wednesday afternoon
about the same as today.
KSFO Bridge Approach... Similar to SFO.
Monterey Bay... Low fog has lifted over SNS and MRY, with the former
now reporting clear skies and the latter hanging on to a scattered
ceiling, although this is expected to dissipate within the hour.
Then VFR throughout the day with breezy winds of 10-15 knots from
the west and northwest. Stratus returns overnight with clearing
expected near 16z.
&&
.MARINE...as of 10:35 AM PDT Tuesday...Strong northwest winds and
possible gale force gusts continue in the northern outer waters
this morning, while more moderate winds are expected in the near-
shore waters. Steep, hazardous short period seas also continue
but diminish through the day. Lighter winds are forecast
Wednesday but will strengthen again by Friday. Light southwest
swell from 14 to 16 seconds continuing through the week.
&&
.FIRE WEATHER...as of 02:40 PM PDT Tuesday...A passing weather
disturbance will bring a slight chance for high-based thunderstorms
late tonight into the first portion of Wednesday. While confidence
in thunderstorm development is low, any storms that develop would
be capable of creating elevated fire weather concerns due to dry
lightning. While uncertain, this potential for thunderstorms
would spread from south to north across the region. Chances begin
around midnight for the Central Coast and reach the Bay Area
during the early to mid morning hours on Wednesday. Chances will
then taper off from south to north during the late morning to
early afternoon hours. Outside of the concern for lightning gusty
and erratic winds are possible in and near thunderstorms, should
they develop. Right now confidence is too low for the issuance of
Fire Weather headlines, however a short-fused Red Flag warning is
*possible* tonight *if* thunderstorms are able to develop.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...Heat Advisory...CAZ504-510-514>518
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pt Arena to Pt Reyes 0-10 nm until 9 PM
&&
PUBLIC FORECAST: MM
AVIATION: Dial
MARINE: Dial
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www.youtube.com/nwsbayareaThe national radar mosaic for the moment the first event began.
3 heat. Local standard time, as filed.
Livermore Coop site reached a daily max record of 107 degrees, besting the previous record of 105 deg set in 1951. Other cities in the zone reached the low to mid 100s.
Both Pinnacles NP and Parkfield recorded max temperature 107 degrees. Various other stations in the zone reported highs between 100 and 106 deg.
Bradley, at the southern end of the Salinas Valley, recorded a max temperature 110 degrees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, August 2022
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1043266, 1043270, 1043271.