An upper level jet diving down the coast of California, combined with plentiful lower level moisture advected from the Pacific set the stage for an early season rain storm and strong winds around much of the Bay Area and Central Coast. The highest winds occurred along the coast, where various sites reported gusts between 35 and 50 mph.
Every event with a place to put it; 11 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.
An upper level jet diving down the coast of California, combined with plentiful lower level moisture advected from the Pacific set the stage for an early season rain storm and strong winds around much of the Bay Area and Central Coast. The highest winds occurred along the coast, where various sites reported gusts between 35 and 50 mph. A wind advisory was in effect from early Sunday morning through Sunday evening for the immediate coast and coastal hills. Highest rainfall totals were recorded in the coastal mountains from Sonoma County southward through Big Sur, resulting in localized flooding, downed trees/powerlines and debris/rocks sliding onto Highway 1 in Big Sur. A flood advisory was issued for a large portion of the Monterey Bay coastal zone and Big Sur coast from late night on the 18th through early morning on the 19th. Storm Total Rainfall measured 2 to 3.5 inches in North Bay Coastal Mountains, 1.5 to 2.2 inches in the Santa Cruz Mountains and 2 to 4.7 inches in the Santa Lucia's. Lower totals closer to an inch or less were recorded around the SF Bay Shoreline and coastal Monterey Bay.
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 Sep 18, 4:59 PM UTC, 1 minute earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
959 AM PDT Sun Sep 18 2022
.SYNOPSIS...Periods of rain with possible thunderstorms today into
tonight. Shower chances stay in the forecast Monday with an upper
low offshore though no all day rain is forecast. Threat of showers
continues into Tuesday as the low stays west of San Francisco. The
low moves inland Wednesday then high pressure builds Thursday into
next weekend with a return to dry and seasonably warm weather.
&&
.DISCUSSION...as of 9:59 AM PDT Sunday...Radar continues to show
bands of rain passing over the Bay Area with more organized bands
offshore. Heaviest rain is currently over northwest Sonoma county,
closer to the upper and surface low where upslope flow is being
maximized in the coastal hills. The Oakridge RAWS reported 0.51
last hour with a storm total of 1.65 inches so far while Cazadero
is up to 1.22 and Venado 1.06. Of course those are the usual wet
spots with lighter amounts across the rest of the North Bay and
generally much lighter so far south of the Golden Gate.
Nonetheless the forecast remain on track and more rain bands will
continue to rotate across the region this afternoon into tonight.
Have noted some lightning strikes offshore in the core of the
upper low so the current slight chance of thunderstorms remains
valid as the core of the low gets closer and combines with peak
daytime heating.
Looking at the latest HRRR and NAM model runs expect the most
widespread and steady rain to last through late tonight to around
sunrise Monday. After that band shifts eastward the upper low
still lingers offshore. Will need to wait for afternoon heating on
Monday for next round of showers to develop which look to be most
focused across the interior hills Monday afternoon.
The shower threat continues right into Tuesday with the upper low
offshore and shortwave energy rotating around that suggests more
rain chances Tuesday morning. The low will stay with us through
Weds before finally shifting eastward.
Wind Advisory still looking valid with gusts 35-45 mph being
reported. As the surface low continues to deepen offshore today
still expect persistent southerly flow to continue into tonight.
&&
.AVIATION...as of 4:39 AM PDT Sunday...For the 12Z TAFs. Cloud
bases /MVFR-VFR/ with rain from a very early season low west of
the Bay Area. Rain slowest to begin downstream of downsloping and
drying (shadowing effect) due to south or southeast winds over
mtns/hills. Increasing lower level southerly winds along the inner
coastal waters with land overlap from Sonoma County to northern
Monterey County this morning. The 12z TAFs include mention of low
level wind shear for KSTS, KSFO and KMRY today into this evening.
Instability may become a bit more focused over the North Bay this
afternoon, no mention of thunderstorms in KSTS nor KAPC TAFs yet,
but will continue to monitor satellite and radar through the day
and amend as necessary.
With the low pressure system nearly stationary over the outer
coastal waters tonight through Monday expect additional showers
and a slight chance of thunderstorms along with a mix of MVFR and
VFR. Gusty lower level southerly winds still continuing this
evening, then gradually easing late tonight and Monday. Will
monitor pireps and observations for possible additional low level
wind shear beyond what's currently advertised in the 12z TAFs.
Vicinity of KSFO...MVFR ceiling and rain likely based on recent
radar data. Wind south to southeast 5 to 10 knots. Light rain or
moderate rain developing today along with low level wind shear
beginning by 20z today. Lower level southerly wind nearing 50 knots.
Light rain transitioning to showers along with MVFR continuing
tonight and Monday morning.
KSFO Bridge Approach...Similar to SFO.
Monterey Bay...MVFR ceilings with light and variable winds at the
moment. South to southeast winds increasing to 10 to 20 knots,
stronger gusts 25 possibly locally 30 knots or higher in the
Salinas Valley. Rain shadowing effect initially due to south to
southeast winds, however with incoming rain bands precipitation
will likely begin reaching the ground through morning and
afternoon. MVFR ceilings tonight and Monday with showers.
&&
PRECIP RECORDS
Obviously, there was a big storm back in 1959 that
holds very high records for most of these places on Sept 18. One
exception is for the downtown Oakland site which didn't start
observations until October 1, 1970. At the bottom of these stats,
we provide the Sept Climate Normal based on 1991-2020 and the
September Average based on that station's entire period of record.
You can clearly see that we've been much drier in recent history.
*Forecast rain totals updated as of 4:45 AM 9/18*
Climate Site 9/18 fcst 9/18 record 9/18 normal
Santa Rosa 1.01" 2.82" in 1959 0.01"
Kentfield 1.10" 3.85" in 1959 0.00"
Napa dwntown 1.00" 1.87" in 1959 0.00"
Richmond 0.62" 2.05" in 1959 0.00"
Livermore dwtn 0.25" 0.36" in 1959 0.00"
SF downtown 0.56" 2.01" in 1959 0.00"
SFO airport 0.44" 2.29" in 1959 0.00"
Redwood City 0.26" 3.05" in 1959 0.00"
Half Moon Bay 0.66" 1.10" in 1959 0.00"
Oakland dwtn 0.47" 0.13" in 2019 0.01"
San Jose 0.34" 2.00" in 1959 0.00"
Gilroy 0.38" 0.28" in 1959 0.00"
Salinas arprt 0.18" 0.15" in 1989 0.00"
King City 0.15" 0.35" in 1989 0.00"
Climate Site 9/19 fcst 9/19 record 9/19 normal
Santa Rosa 0.30" 0.34" in 1959 0.00"
Kentfield 0.24" 1.65" in 1959 0.00"
Napa dwntown 0.43" 0.51" in 1977 0.01"
Richmond 0.25" 0.71" in 1977 0.00"
Livermore dwtn 0.27" 1.53" in 1959 0.01"
SF downtown 0.20" 0.83" in 1977 0.01"
SFO airport 0.21" 0.46" in 1977 0.00"
Redwood City 0.32" 0.82" in 1977 0.01"
Half Moon Bay 0.17" 2.56" in 1959 0.01"
Oakland dwtn 0.27" 0.59" in 2004 0.00"
San Jose 0.34" 0.58" in 1977 0.01"
Gilroy 0.27" 5.97" in 1959 0.00"
Salinas arprt 0.22" 0.20" in 1966 0.00"
King City 0.29" 0.10" in 1959 0.00"
Climate Site Fcst Storm Total Sept Monthly Record
Santa Rosa 1.48" 4.39" in 1904
Kentfield 1.46" 3.85" in 1959
Napa dwntown 1.54" 4.79" in 1904
Richmond 0.91" 2.05" in 1959
Livermore dwtn 0.50" 5.72" in 1918
SF downtown 0.79" 5.07" in 1904
SFO airport 0.71" 2.29" in 1959
Redwood City 0.47" 3.05" in 1959
Half Moon Bay 0.91" 2.56" in 1959
Oakland dwtn 0.77" 1.54" in 1986
San Jose 0.53" 6.33" in 1918
Gilroy 0.70" 5.97" in 1959
Salinas arprt 0.41" 1.22" in 1976
King City 0.46" 1.67" in 1918
Climate Site Sept Climate Normal (1991-2020) Sept Avg (all data)
Santa Rosa 0.15" 0.38"
Kentfield 0.09" 0.27"
Napa dwntown 0.09" 0.31"
Richmond 0.03" 0.15"
Livermore dwtn 0.09" 0.21"
SF downtown 0.10" 0.25"
SFO airport 0.07" 0.13"
Redwood City 0.07" 0.13"
Half Moon Bay 0.21" 0.20"
Oakland dwtn 0.10" 0.23"
San Jose 0.07" 0.22"
Gilroy 0.04" 0.25"
Salinas arprt 0.05" 0.11"
King City 0.06" 0.09"
&&
.MARINE...as of 09:11 AM PDT Sunday...A very early season low
pressure system is located over the outer coastal waters west of
Point Reyes. The low will become stationary over the outer waters
until late Tuesday and Wednesday when the low will begin moving
northeast away from the coastal waters and bays. A new northwest
swell arrives by Tuesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...Wind Advisory...CAZ006-502-503-505-509-512-529-530
SCA...SF Bay
SCA...Mry Bay from 3 PM
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
&&
PUBLIC FORECAST: RW
AVIATION: Behringer
MARINE: Behringer
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www.youtube.com/nwsbayareaThe national radar mosaic for the moment the first event began.
11 strong wind, 3 flood. Local standard time, as filed.
Strong gust 44 mph measured by PG&E Mill Creek Vineyard weather station.
Minor flooding due to heavy rain on Rt-17 offramp.
Highway 1 closed between Point Lobos and Ragged Point due to highway flooding and weather conditions.
Strong gust 46 mph measured by PG&E Stewarts Point weather station on Highway 1.
Six to eight inch diameter branches blocking road at Bear Creek Rd and Huckleberry Ln.
Peak gust measured at 43 mph by Woodacre RAWS.
Tree fell down onto roadway at Carmel Valley Rd and Carmel Rancho Blvd.
Tree collapsed near roadway, blocking lanes. Law enforcement closed both lanes on Highway 17 north of Scotts Valley.
Peak gust 47 mph measured by PG&E weather station at Pt Reyes.
Tree down blocking road at 3042 Soquel San Jose Rd.
Tree fell down onto northbound lane of Highway 1 between Dolan and Esalen.
Tree and power lines down in roadway on highway at top of western in Ben Lomond.
Maximum gust 50 mph measured by CalFire Portable RAWS at 743 ft elevation.
Social media report of flooding in roadways in pacific grove after 45 minutes of heavy rainfall.
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, September 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: 1059308, 1059193, 1059221, 1059298, 1059241, 1059295, 1059259, 1059269, 1059294, 1059250, 1059256, 1059282, 1059291, 1059206.