A strong front entered Western Washington, bringing another round of heavy mountain snow.
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 SEW wrote it up.
A strong front entered Western Washington, bringing another round of heavy mountain snow.
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 Seattle, WA wrote its last area forecast discussion before the first event at Feb 13, 3:33 AM PST, 2 hours 27 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
333 AM PST Mon Feb 13 2023
.SYNOPSIS...A passing front will move through Western Washington
today bringing cooler air and strong onshore flow, along with
additional lowland rain and mountain snow. Snow levels continue to
fall into Tuesday morning with some light snow showers possible to
sea level as moisture tapers. Drier conditions are expected midweek,
with temperatures returning to near seasonal normals.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...Current satellite shows the
front just along the coast and gradually making its way inland,
which is confirmed by current radar showing the main band of precip
there. A point of interest ahead of this though is what looks to be
a SW to NE running convergence zone over central Snohomish County
extending into the Cascades of Skagit. This helps to shore up some
degree of confidence in the headlines that will be discussed below.
As the front passes through the area today and its parent upper
level low right behind it, a wet period is on tap through much of
the day today. This one-two punch may be enough to import some
slight instability to the area. LIs look a little bit better than 24
hours ago...but still not terribly impressive, as values only get as
low as zero...maybe -0.5. Still, some weak CAPE will be present, not
only along the coast and coastal waters but also over the Cascade
foothills...where this combo of slight instability, the passing
front and mechanical forcing may prove just enough to trigger an
isolated thunderstorm here or there.
Returning to the aforementioned convergence zone, inherited headlines
included a Winter Storm Warning for the Central Cascades as well as
a Winter Weather Advisory for the Cascades of Pierce and Lewis
Counties...the reasoning for the difference being that the Central
Cascades are expected to see more snowfall thanks to the expectation
of a convergence zone as snow levels fall throughout the day. Given
the current orientation of the already present convergence zone,
feel better about including the North Cascades into the headlines as
well since the forecast still shows expected snowfall amounts right
around the low end of Winter Weather Advisory criteria.
While speaking of headlines, it is worth mentioning that the frontal
passage will result in breezy to locally windy conditions throughout
W WA this afternoon and evening. The coast as well as the Eastern
Strait and Admiralty Inlet area are likely to see the highest wind
speeds, meeting Wind Advisory criteria and as such, that inherited
headline will remain in place. Additionally, for the coast the
combination of these winds and high seas will make for high surf
conditions along the coast and as such, a High Surf Advisory will
also remain in effect.
But wait...there is more. Colder temperatures after FROPA will
translate into lowering snow levels, with most locations seeing snow
levels below 500 feet by midnight tonight. These will continue to
fall during the overnight period, reaching Sea Level for much of W
WA by Tuesday morning. Although precipitation chances will diminish
as this is occuring, there appears to be enough overlap to entertain
the prospect of some lowland snow showers. Data continues to suggest
minimal accumulation...if any...for most locations. However, the
Southwest Interior may see PoPs linger there long enough for some
accumulation by early Tuesday morning. Latest models suggest amounts
between a half-inch and an inch being strictly confined to portions
of Lewis County. Confidence is not there for amounts that would
warrant any kind of Advisory down there at this time, but it is a
situation that will definitely need to be monitored as a short-fused
headline is not out of the question.
Conditions are expected to be dry by late Tuesday morning/early
Tuesday afternoon as an upper level ridge works its way into the
area, although daytime highs will only creep into the lower to mid
40s. These dry conditions are expected to extend throughout
Wednesday as well, with high temps generally in the mid 40s
throughout the CWA. 18
.LONG TERM /THURSDAY THROUGH SUNDAY/...Deterministic models are in
some agreement keeping even Thursday dry for the most
part...although the GFS is more progressive with the exit of the
ridge and has precip starting as early as Thursday evening.
Deterministic ECMWF keeps conditions dry even into Friday. Ensemble
solutions are a bit scattered, mainly due to disagreement on the
track of the next incoming system. Deterministic ECMWF wants to take
the system down along the coast into CA, likely the driest scenario.
Ensembles appear to be leaning in that direction, however not quite
as clear cut with some precip working inland into portions of W WA.
The extended forecast follows this trend, more dry than wet, meaning
higher PoPs along the coast while only 20-40 pct for inland
locations. Thus, not a wet forecast, certainly, but still lacking
the confidence to remove precip entirely.
For as fuzzy as all that seems, at least temperatures will be on the
upswing, even approaching seasonal normals by the end of the week.
Daytime highs will start off in the mid to upper 40s Thursday before
getting into the upper 40s to lower 50s for the weekend. Overnight
lows will remain a little brisk, generally in the lower to mid
30s...perhaps creeping into the upper 30s to around 40 over the
weekend. 18
&&
.AVIATION...The air mass will remain cool, moist, and unstable
today with strong onshore flow and an upper level trough. Showers
will mostly impact the coast and mountains with a slight chance of
thunderstorms. However, heavier showers may be found in Snohomish
and King counties today due to a Puget Sound Convergence Zone.
Showers will taper down tonight as onshore flow weakens. 33
KSEA...Showers in the vicinity today with strong onshore flow. The
convergence zone may shift south over the terminal late this
afternoon and evening. The air mass will remain cool with low snow
levels overnight but the chance of accumulating snowfall (1" or
greater) is low at 10-15 percent. Otherwise, drier conditions
expected Tuesday afternoon. 33
&&
.MARINE...Strong onshore flow will continue today with gales
or small craft advisories over all waters. A large swell train will
reach the coast tonight with 17 to 22 foot seas. The flow will ease
on Tuesday then turn weakly offshore on Wednesday (with seas
subsiding under 10 feet). A second, weaker, frontal system will move
through the area Thursday and Thursday night. 33
&&
.HYDROLOGY...No river flooding is expected through the next seven
days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from noon today to midnight PST tonight for
Admiralty Inlet Area-Central Coast-Eastern Strait of Juan
de Fuca-North Coast.
High Surf Advisory from noon today to 4 AM PST Tuesday for
Central Coast-North Coast.
Winter Weather Advisory until 10 PM PST this evening for West
Slopes North Cascades and Passes.
Winter Storm Warning until 11 PM PST this evening for West
Slopes North Central Cascades and Passes.
Winter Weather Advisory from 7 AM this morning to 10 PM PST this
evening for West Slopes South Central Cascades and Passes.
PZ...Small Craft Advisory until 4 AM PST Wednesday for Grays Harbor
Bar.
Gale Warning until midnight PST tonight for Admiralty Inlet-
Coastal Waters From Cape Flattery To James Island Out 10 Nm-
Coastal Waters From James Island To Point Grenville Out 10
Nm-Coastal Waters From Point Grenville To Cape Shoalwater
Out 10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 10 PM PST this evening for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
Small Craft Advisory until 4 AM PST Tuesday for Northern Inland
Waters Including The San Juan Islands.
Small Craft Advisory until 10 PM PST this evening for Puget
Sound and Hood Canal.
Gale Warning until 10 AM PST Tuesday for Coastal Waters From
Cape Flattery To James Island 10 To 60 Nm-Coastal Waters
From James Island To Point Grenville 10 To 60 Nm-Coastal
Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.
&&1 heavy snow. Local standard time, as filed.
Observations show that during a 12 hour period in the Central Cascades, within a 12 hour period, 12 inches of snow fell when a Winter Storm Warning was in place. Totals also increased afterwards due to the presence of the Puget Sound Convergence Zone.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2023Every state in 2023This day in weather historyWarnings in Washington, February 2023
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: 1084581.