A band of showers over the northern Washington brought heavy snow amounts to the Methow Valley. Many locations across Eastern Washington received snow amounts of one to four inches.
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The episode as NWS OTX wrote it up.
A band of showers over the northern Washington brought heavy snow amounts to the Methow Valley. Many locations across Eastern Washington received snow amounts of one to four inches.
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 Spokane, WA wrote its last area forecast discussion before the first event at Mar 5, 2:21 AM PST, 29 minutes earlier.
Area Forecast Discussion
National Weather Service Spokane WA
221 AM PST Sun Mar 5 2023
.SYNOPSIS...
Periods of snow today with generally light accumulations.
Blustery northeast winds Sunday into Monday will deliver a
reinforcing shot of chilly air into our region with cooler than
average temperatures expected to persist next week. Intermittent
snow showers will continue throughout the week and weekend.
&&
.DISCUSSION...
Today through Monday: A tricky and complicated forecast this morning
and afternoon as a band of precipitation slowly pivots around an
offshore low and lifts through the Inland Northwest. As of 2AM,
the band of precipitation stretched from the Blue Mountains and
Camas Prairie northwest across the Columbia Basin into the Methow
Valley with lighter, "satellite" showers rotating ahead of the
main band across the Palouse and Okanogan Highlands. Shortwave
energy lifting northward from around Mt St Helens will begin
interacting with this moisture band within the next 2-6 hours and
we should begin to see precipitation intensity increasing with
narrow bands of moderate to heavy rates. These intensities will
not be widespread across the entire precipitation band so some
areas could receive well over a quarter of an inch of liquid and
others under a tenth. The second component that complicates
matters are the temperature profiles near the surface. Current
temperatures within most lowlands from the L-C Valley to south of
Ritzville to Moses Lake and East Wenatchee are running between
33-37F. This will result in very wet, non accumulating snow or
even rain/snow mix limiting accumulation potential unless the
precip intensity can reach moderate to heavy rates. For most
locations above 1500 feet, snow has been observed on cams with
light accumulations at times. Northeast winds are being drawn into
the low and are quite breezy across the North Idaho Panhandle and
Northeastern WA. Wind gusts near 25 mph have been common
throughout the evening and will continue into Sunday afternoon.
This is drawing drier air and dewpoints into the region which will
assists in lowering snow levels from wet bulb cooling.
My main uncertainty at this time is how much of the precipitation
will backfill into the Wenatchee Mountains, Wenatchee River
Valley, and southern Douglas County. The band currently seen on
radar has lifted north of these areas. The NAM/RAP suggest these
areas are done and the aforementioned interaction with the
shortwave will take place further north. The HREF, HRRR, GFS, and
ARW suggest this will begin to fill back in the next hour or two.
Will need to closely monitor trends in the next few hours and
adjust the forecast as necessary.
Otherwise, the band of precipitation largely falling as snow will
slowly drift northward through the day reaching the Canadian
border Sunday evening. Snow covered roads will be possible through
the morning but the early March sun angle should limit additional
travel impacts to the mountains by the afternoon hours. The band
will likely struggle to actually lift north of the border and
mostly fall apart over the northern mountains Sunday night. A
second wave pivoting around the low will cross the WA/OR border
early Monday morning. This wave looks weaker but could bring a
renewed threat for light snow Monday morning and mix of rain/snow
Monday afternoon. General consensus is for this wave to shear
apart as it crosses into the region then afternoon heating
triggering a resurgence of hit or miss showers Monday afternoon,
especially in the Cascades, Blue Mountains, and lower Idaho
Panhandle. /sb
Tuesday through Thursday: Main story is below average temperatures
during the workweek and intermittent rain/snow showers. Impacts will
be minimal in the lowlands where temperatures will be too warm for
snow. Snow showers could lead to slick road conditions at the
Mountain Passes.
Friday/Saturday/Sunday: It is looking increasingly likely that a
storm system impacts the INW by the end of the week. 68% of the
global ensembles indicate a deeping low NW of Vancouver Island
slowly meandering SE towards Washington. The east slopes and
Cascades look to be favored for this event with upslope flow.
Impacts will be minor with the drawn out nature of the system and
marginal surface temperatures in the lowlands. 72 hour snowfall
probabilities through Sunday morning are below:
Lowlands: >1", >4", >6", >8"
-Spokane - 50%, 10%
-Sandpoint - 50%, 15%
-Methow Valley - 70%, 60%, 40%, 25%
-Wenatchee - 50%, 20%
Mountain Passes: >6", >8", >12", >18"
-Stevens Pass - 75%, 70%, 60%, 25%
-Blewett Pass - 70%, 50%, 30%, 5%
-Lookout Pass - 40%, 25%, 15%, 3% /Butler
&&
.AVIATION...
06Z TAFS: A band of snow over the Cascades down through the Blue
Mountains will slowly lift north and east into Sunday morning.
Runway accumulations are most likely for Wenatchee, Chelan,
Winthrop, and Pullman given the snow will be occurring overnight
into early Sunday morning. For Moses Lake and Lewiston an earlier
start as well but temperatures may be marginal for runway
accumulations. For Spokane, Coeur d'Alene, Colville, and Sandpoint
most of the snow is expected during the day on Sunday which will
make runway accumulations difficult given the early March solar
energy. An increase in areal snow will result in a deteoriation of
conditions from VFR to MVFR with IFR conditions possible under
heavier snow bands, as well as the East Slopes of the Cascades
under moist easterly boundary layer flow. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 37 23 36 20 36 15 / 70 20 20 0 10 0
Coeur d'Alene 37 22 35 18 37 13 / 70 40 10 0 10 0
Pullman 37 25 34 22 36 17 / 90 20 30 10 10 10
Lewiston 45 30 40 25 40 19 / 90 10 20 10 10 0
Colville 37 23 35 20 35 11 / 30 50 10 0 10 0
Sandpoint 34 22 30 19 32 11 / 10 20 10 10 20 0
Kellogg 35 20 32 17 32 11 / 80 40 40 10 30 0
Moses Lake 42 29 41 25 42 24 / 70 10 10 0 0 0
Wenatchee 37 28 33 25 31 17 / 100 20 10 0 10 0
Omak 37 27 33 23 32 15 / 70 50 0 0 10 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 10 AM PST this morning for Lewis
and Southern Nez Perce Counties.
WA...Winter Weather Advisory until noon PST today for Central Chelan
County-Waterville Plateau-Wenatchee Area-Western Chelan
County.
&&The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Observer nine miles west of Twisp reported 8.7 inches of snow at 0700PST. Other reports in the area ranged from 5 to 9 inches.
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, March 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: 1089287.