Heavy Snow in Oregon, February 15 to 17, 2025

Area Forecast Discussion
National Weather Service Portland OR
354 PM PST Sat Feb 15 2025

.SYNOPSIS...A frontal system returns widespread rain and Cascade
snow through Monday. Heavy snow and hazardous travel expected for
the Cascade passes tonight through Monday morning. The Upper Hood
River Valley will also see another round of winter weather impacts
tonight into Sunday morning, mainly from snow and/or freezing rain.
Expect more milder temperatures early next week, with another
weather system arriving mid-week. Likely drier and trending warmer
late next week.

&&

.SHORT TERM...Now through Monday Night...A Pacific weather system
will bring widespread rain and mountain snow to the region tonight
through Monday. A warm front currently lifting across NW Oregon is
expected to push snow levels up to 4000-5000 ft by Sunday morning.
Temperatures are warming this afternoon into the upper 30s to lower
40s, except to around 50 degrees near Eugene and along the coast
from Tillamook southward. With cloudy skies and increasing southerly
winds overnight, temperatures aren't expected to fall much below 40
degrees, except in the Hood River Valley and the high Cascades.
Precipitation increases tonight ahead of a trailing cold front
associated with a strong, southwest upper level jet pushing into
western Oregon. The cold front will stall out along the coast Sunday
morning before the next upper shortwave trough moves across the area
later Sunday, which is expected to enhance precipitation rates Sunday
night through Monday morning and lower snow levels slightly to
around 3500-4000 ft. Another upper shortwave trough in more
northwest flow aloft brings one more round of enhanced precip for
Monday afternoon.

Most of the area will see total 48-hour rainfall amounts of around
0.50 to 1.50 inches, higher amounts along the coast and lower end
amounts inland. Higher terrain, including the Coastal Mountains,
Willapa Hills and the Cascade foothills below 3500 ft are more
likely to see 48-hour rainfall amounts of around 2 to 4 inches. This
will likely bring a rise in local rivers, but hydro concerns remain
low as there is less than a 5% chance of reaching action stage.
Above 3500 ft, heavy snow is expected. This includes the Cascade
passes where a Winter Storm Warning is in effect from 10 PM this
evening through Monday morning. Expect total snowfall amounts of 1
to 2 feet in the Cascades, with a 5-10% chance of 2 feet or more at
pass-level. Those traveling through the Cascades should prepare for
winter weather and refer to ODOT/WSDOT for the latest road
conditions and restrictions.

Another area of concern with the initial push of this system will be
across the central Columbia River Gorge, east of Cascade Locks, and
the Upper Hood River Valley. Surface temperatures, currently in the
lower to mid 30s, are forecast to fall below freezing tonight, which
would support another round of wintry precipitation. Confidence
remains high in wintry precip occurring, likely starting out as
snow, before transitioning to sleet/freezing rain Sunday morning,
and then to rain as surface temperatures rise above freezing. The
latest HREF indicates a 60-70% chance of at least 1 inch of snow,
and a 10-20% chance of at least 0.10 inch of ice. Will maintain the
Winter Weather Advisory in place for the Upper Hood River Valley
through Sunday morning, with 1 to 3 inches of snow and up to a tenth
inch of ice possible for elevations above 500 ft. There is a little
more uncertainty in wintry precipitation for the central Gorge,
including I-84, as temperatures likely hover around 32-33 degrees.
Will likely see snow fall, but significant accumulations are not
expected at this time.

Winds also become breezy this evening, but will likely be short
lived. Southerly winds along the coast are expected to gust up to 35-
45 mph between 6 PM and Midnight, while easterly winds near the
Columbia River Gorge see gusts up to 20-30 mph.  /DH

&&

.LONG TERM...Tuesday through Saturday...By Tuesday, ensemble
guidance is in good agreement in a shortwave ridge shifting over the
Pacific NW between weather systems. Mostly dry weather is expected
through Tuesday afternoon, except for a few showers over the
Cascades and Coast Range. Temperatures also continue to warm with
lowland high temperatures in the lower to mid 50s and overnight
temperatures only dropping to the 40s with morning fog.

Models and their ensembles suggest another Pacific weather system
brings additional widespread precipitation to the region late
Tuesday through Wednesday. Once again rain is expected for most
locations west of the Cascades, including the lowlands, but snow is
possible once again in the Upper Hood River Valley and central
Columbia River Gorge. There is lower confidence in specifics at this
time on snow probabilities and amounts. Snow is also likely to
return over the Cascades. No significant impacts are expected with
this system at this time, but keep an eye on the forecast as details
change.

Ensemble guidance generally in good agreement through late next week
as well with various degrees of upper level ridging being shown the
the clusters. Most clusters keep the area dry, although there is
around a 20% chance the ridge breaks down and allows more rain
across NW Oregon and SW Washington. If the drier solutions win out,
then more likely temperatures are expected to continue to trend
warmer, potentially into the mid 50s. /DH

&&

.AVIATION...A warm front was continuing to lift northward over
northwest OR and southwest WA, bringing isolated light rain
showers with it. That being said, most of these rain showers were
only producing virga as of 22z Saturday, meaning precipitation is
evaporating before reaching the ground with most of these
showers. Cigs have also lifted to VFR thresholds at all TAF sites,
aside from KHIO and KSLE where where a broken cloud deck was
lingering at 400 and 700 ft, respectively. Suspect low clouds to
linger throughout the TAF period at these two TAF sites, however
cigs may temporarily lift to low-end MVFR thresholds towards
03-04z Sunday.

As the aforementioned warm front continues lifting northward, a
cold front over the coastal waters will continue pushing eastward
towards the coast. This will bring widespread stratiform rain to
the coast beginning sometime between 00-03z Sunday before pushing
across the Willamette Valley and Portland/Vancouver metro between
03-06z Sunday. This should bring lowering cigs at the coast,
likely lowering to IFR thresholds (80-90% chance) by 06-09z
Sunday. Widespread MVFR cigs with isolated pockets of IFR cigs
will likely occur for the inland terminals with this next round
of stratiform rain.

PDX AND APPROACHES...Fog and low clouds have lifted at the KPDX
terminal as of 22z Saturday, giving way to VFR high clouds. Another
round of rain will move in towards 04z Sunday, bringing
increasing chances for MVFR cigs (50% chance by 06z Sunday
increasing to a 90% chance towards 09z Sunday). Chances for MVFR
cigs decrease to 30% by 15z Sunday as precipitation transitions
from a steady stratiform rain to off-and-on rain showers. -TK

&&

.MARINE...At 2:30 PM Saturday, a frontal system was beginning to
move over the coastal waters, bringing increasing southerly winds.
Buoy observations showed seas around 7 to 8 ft at 12 to 15 seconds
with winds around 15 to 20 kt with gusts up to 25 kt. Expect wind
gusts to increase to 30 kt Saturday evening over the outer waters
and Saturday night over the inner waters. Brief and isolated gale
force gusts up to 35 kt will be possible in all marine zones,
including the Columbia River Bar. However, wind gusts of this
magnitude are not expected to be widespread or prolonged enough to
justify the issuance of a Gale Warning. Therefore, a high-end
Small Craft Advisory remains in effect.

Seas will gradually build through the weekend, reaching 13-15 ft
Sunday night into Monday before lowering a bit on Tuesday.
Another frontal system arrives Tuesday night into Wednesday,
bringing another round of increased winds and elevated seas.
Similar to Saturday evening/night, expect this frontal system will
once again bring widespread wind gusts up to 30 kt with brief and
isolated gale force wind gusts up to 35 kt possible. -TK

&&

.BEACH HAZARDS...A long period westerly swell is entering our
coastal waters late today around 9 ft at 14 to 15 seconds,
building towards 12 ft at 13 seconds by Sunday morning. It appears
the dominant wave period will increase back to 15 seconds Monday
morning with swell heights around 13 to 14 ft. This will result
in an increased threat for sneaker waves along all coastal
beaches, with the highest threat being Sunday night through Monday
morning. Therefore, a Beach Hazards Statement remains in effect
through Monday morning to help raise awareness regarding the
increased threat for sneaker waves. Beachgoers should remain
vigilant for waves occasionally running up much farther onto the
beach than background wave conditions. Stay off of rocks, jetties
and logs. Never turn your back on the ocean. -42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Winter Weather Advisory until 1 PM PST Sunday for ORZ121.

     Winter Storm Warning from 10 PM this evening to 10 AM PST Monday
     for ORZ126>128.

WA...Winter Storm Warning until 10 AM PST Monday for WAZ211.

PZ...Small Craft Advisory until 10 PM PST Sunday for PZZ210.

     Small Craft Advisory until 4 AM PST Monday for PZZ251>253-
     271>273.
&&

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