Another cold area of low pressure moved south along the Oregon coast and produced significant snow from the coast to the Cascades with snow levels around 500 feet at the Coast Range and 1000 feet east of the Coast Range to the Cascades.
Every event with a place to put it; 6 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 MFR wrote it up.
Another cold area of low pressure moved south along the Oregon coast and produced significant snow from the coast to the Cascades with snow levels around 500 feet at the Coast Range and 1000 feet east of the Coast Range to the Cascades.
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 Medford, OR wrote its last area forecast discussion before the first event at Feb 21, 2:46 AM PST, 1 hour 14 minutes earlier.
Area Forecast Discussion
National Weather Service Medford OR
246 AM PST Tue Feb 21 2023
SHORT TERM...Today through Thursday...Radar imagery shows
precipitation spreading into southern Oregon from the north and
west. This is the start of an active and potentially very
impactful week of weather, and the strong cold front producing
this precipitation will pass through the forecast area this
morning. Winter Storm Warnings are already up for the mountains.
These will continue, along with additional Warnings and
Advisories, over the next 24 to 36 hours.
A strong mid-level jet (50-60kt) will cause some gusty winds over
the East Side today, so we have Wind Advisories up for that at
NPWMFR. Usual suspect locations over there like Summer Lake could
have a peak wind gusts of 55+ mph, but the majority of the area
will have gusts in the 45-55 mph range (this includes Klamath
Falls).
Most of the precipitation will be post-frontal and associated
with a sharp upper trough passing through the area around midday.
Strong WNW orographic lift into the Cascades and Siskiyous will
maintain periods of heavy snow there, perhaps with rates of 1" per
hour at times. All told, we're expecting 10-20 inches of snow in
the mountains by Wednesday morning, though a bit lower totals of
4-8 inches over the Siskiyou Summit. There will be some spillover
east of the Cascades, especially from the intersection of highway
138 northward up highway 97 to La Pine (3 to 6 inches), but the
vast majority of the East Side will be in a downslope flow and
snow amounts will be drastically lower. Even so, they won't be
without impacts since winds will blow around any snow that does
fall or is still on the ground.
Meanwhile, snow levels will be crashing west of the Cascades,
falling to around 1500 feet by late Tuesday morning. We have
Winter Storm Warnings up for elevations above 1500 feet Tuesday
afternoon since there are concerns about possible snow
accumulations on the lower I-5 passes north of Grants Pass and
surrounding higher terrain of Jackson/Josephine counties before
the evening rush. It will take some time for the snow levels to
fall low enough in the valleys west of the Cascades, but we do
expect them to come down to around 1000 feet Tuesday evening, then
500 feet overnight into Wednesday morning. At least a few inches
are likely for the aforementioned passes and surrounding higher
terrain, but where there's more upslope in eastern Jackson County
(up toward Butte Falls/Prospect), there could be more than 6
inches of snow. For here in Medford, Grants Pass and the lower
valley locations around Roseburg, precipitation amounts are
trickier due to its showery nature. Most locations down to 500
feet will have at least some snow accumulation by Wednesday
morning, but it's not out of the question that some areas get
totally missed. That's how it works around here. With snow levels
so low and showers around, we need to be forecasting at least some
small amounts. Winter Weather Advisories are up for elevations
below 1500 feet in Jackson/Josephine Counties, and down to around
500 feet in Douglas County. We also have Winter Weather Advisories
up for the coastal zones above 500 feet. It should be noted that
it will get quite convective around here Tuesday afternoon into
Tuesday evening with model instability showing a decent chance at
lightning pretty much anywhere west of the Cascades beneath the
cold pool aloft. Small hail is possible in any of the heavier
showers, especially over the ocean and along the coast.
By Wednesday afternoon, there should be enough solar insulation to
send road surface temperatures above freezing for most of the
lower elevations (below 2500 feet) west of the Cascades, even
while the air mass remains cold enough to support snow showers.
This should result in melting of any falling snow on roads (though
the exception will be in heavier snow showers where it could
result in brief slushy roads, before melting once again as heavier
showers move away or ease up in intensity). High temperatures
during this period will be 10 to 20F below normal in most cases,
which may challenge record low maximum temperature values in some
locations.
Models continue to show surface low pressure just off the NW
Oregon Coast Wednesday evening, and a closed upper low wobbling
southward just offshore Wednesday night into Thursday. The cold
air mass is already in place, and we expect a continuation of
showers to develop surrounding the periphery of the low. These
will likely be focused along the coast. It is pretty difficult to
predict this in advance, because, frankly, there just aren't that
many times in the historical record of accumulating snow at the
beaches. However, there is enough evidence today to issue a Winter
Storm Watch for coastal zones 21 and 22 during this time period.
NBM probabilities of 1" or more of snow are fairly high 60-80%
along the Highway 101 from North Bend down to Brookings and there
is even a decent chance at 2" or more with higher amounts above
500 feet. Extreme forecast indices and shift of tails data from
the ECMWF are also showing decent values along the coast, which
indicates that this could be a rare event with respect to the
climatological record. Felt it was a good idea to get out ahead
of it and issue the watch. Farther inland, since we already have a
lot of headlines out, in the interest of clarity, we opted not to
add any more, but I envision at least some other winter products
will be out for this time period, for low elevation areas west of
the Cascades.
Cold low pressure continues to drop south along the NorCal coast
Thursday night, and this puts much of our area under diffluent
flow aloft. The associated lift will continue to produce at least
light snow over most of our area for a period of time Thursday
night. However, at the same time, much drier air will be working
in from the north with snow ending from north to south. The lift
and snow potential is most pronounced over Northern California,
but with low pressure and associated dynamics still so close by,
we are all at risk of some snow impacts continuing into Thursday
night. It's too early to sort these details, but as we get closer
these details will begin to emerge.
Snow ends by Friday as dry, cold air settles in across the area.
Friday morning's low temperatures will likely be quite cold with
temperatures down to near zero east of the Cascades to the upper
teens west of the Cascades. This cold air will also impact the coast
with low temperatures Friday morning in the low to mid 20s in most
locations. These temperatures will also be affected by snow pack,
and those locations with fresh snowpack (which many be many by that
point ), may very well see temperatures lower than we currently have
forecast. Saturday will also feature a cold start, but then some
temperature moderation will occur during the afternoon.
Just when you think maybe it's over, another system spreads rain and
mountain snow back into the area Sunday, and this will be followed
by more cold air which will probably have us worried about potential
valley snow AGAIN early next week. -Spilde/Wright/BPN
&&
.AVIATION...21/06Z TAFs...A warm front is currently pushing into the
forecast area with LIFR ceilings along the coast and MVFR ceilings
farther inland. These should persist for most of the overnight
hours with rain showers persisting through the TAF period. Rain may
be heavy at time when the cold front moves through later Tuesday
morning. A few rumbles of thunder remains possible behind the front
as the airmass becomes unstable. Snow levels will lower to the
valley floors near the tail end of the TAF period with snow in the
forecast for MFR Tuesday evening into Tuesday night.
-Smith
&&
.MARINE...Updated 200 AM Tuesday, February 21, 2023...A very
strong northwest swell moves into the outer coastal waters today and
pushes to the inner waters tonight. This will be accompanied by a
strong cold front moving down the coast today.
This front will bring northwest gales and very high and steep seas
to the area today, with seas continuing to build into Wednesday. The
swell that will arrive behind this front has been consistently shown
to arrive at a period of 13 to 14 seconds, keeping it 1 to 2 seconds
below our criteria for a long period swell. However, the forecasted
peak of 22 to 30 feet Tuesday night into Wednesday afternoon would
meet the criteria for very high and very steep seas. Seas will
remain very steep into Thursday and unsettled weather will continue
through the week.
-Smith/CSP
&&
.BEACH HAZARDS...Updated 200 AM Tuesday, February 21, 2023...
Heavy swell will lead to high surf conditions this afternoon and
last through Wednesday night. While the entire Southern Oregon
coastline is expected to have average breaker heights of 20 to 25
feet, northwest facing portions of the shoreline are anticipated to
have the highest breaking waves. These breaking waves are expected
to create hazardous conditions along and within the surf zone, and
could inundate beaches and low lying shorelines, leading to erosion
in those areas. Take action now to reinforce or remove
infrastructure from the surf zone, as waves this size may also
damage exposed infrastructure.
&&
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 4 PM PST this afternoon for ORZ029>031.
High Surf Advisory from 1 PM this afternoon to 4 AM PST Thursday
for ORZ021-022.
Winter Weather Advisory from 4 PM this afternoon to 10 AM PST
Wednesday above 500 feet for ORZ021-022.
Winter Storm Watch from Wednesday evening through Thursday
morning for ORZ021-022.
Winter Storm Warning from 10 AM this morning to 10 AM PST
Wednesday above 1500 feet for ORZ023-024-026.
Winter Weather Advisory from 4 PM this afternoon to 10 AM PST
Wednesday above 500 feet for ORZ023.
Winter Weather Advisory from 4 PM this afternoon to 10 AM PST
Wednesday below 1500 feet for ORZ024-026.
Winter Storm Warning until 10 AM PST Wednesday for ORZ025-027.
Winter Storm Warning until 10 AM PST Wednesday for ORZ028.
Winter Storm Warning until 4 AM PST Wednesday for ORZ030.
CA...Winter Storm Warning from 10 AM this morning to 4 PM PST
Wednesday above 2000 feet for CAZ080.
Winter Weather Advisory from 1 PM this afternoon to 4 PM PST
Wednesday for CAZ080.
Winter Weather Advisory from 1 PM this afternoon to 4 PM PST
Wednesday for CAZ081-082.
Wind Advisory until 4 PM PST this afternoon for CAZ084.
Wind Advisory from 7 AM this morning to 4 PM PST this afternoon
for CAZ085.
PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST this
morning for PZZ350-356-370-376.
Small Craft Advisory from 4 AM to 10 AM PST Thursday for PZZ350-
356.
Hazardous Seas Warning from 10 AM this morning to 4 AM PST
Thursday for PZZ350-356.
Gale Warning from 10 AM this morning to 4 PM PST Wednesday for
PZZ370-376.
Hazardous Seas Warning from 10 AM this morning to 10 AM PST
Thursday for PZZ370-376.
&&The national radar mosaic for the moment the first event began.
6 heavy snow. Local standard time, as filed.
National gridded snowfall analysis indicated 5 to 10 inches of snow at elevations above 500 feet.
The national gridded snowfall analysis indicated 2 to 8 inches of snow at elevations above 1000 feet.
The national gridded snowfall analysis indicated 2 to 6 inches of snow in valleys and 5 to 10 inches of snow in the surrounding mountains.
The national gridded snowfall analysis indicated 6 to 12 inches of snow at elevations above 1500 feet, and 2 to 6 inches in the lower elevation western portion of the zone.
The national gridded snowfall analysis indicated 4 to 8 inches of snow at elevations above 1500 feet.
Crater Lake reported 21.6 inches of snow. Willamette Pass reported 15.5 inches of snow. National gridded snowfall analysis indicated 10 to 18 inches of snow in the zone.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2023Every state in 2023This day in weather historyWarnings in Oregon, 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: 1084070, 1084071, 1084072, 1084073, 1084074, 1084075.