High Wind in Oregon, January 12 to 13, 2023

Area Forecast Discussion
National Weather Service Pendleton OR
305 AM PST Thu Jan 12 2023

.SHORT TERM...
Today through Saturday night....An area of low pressure well of
the coast will continue to move northward. Southwesterly flow
today will become strong southerly as warm front moves across the
region today, bringing precipitation, mainly this morning, before
tapering off during the afternoon and evening hours, except over
the Cascades. Generally dry weather is expected Friday, outside of
the Cascades.

An area of low pressure will approach the coast of Oregon from the
south on Saturday and will touch off another round of
precipitation, mainly over the mountains though there is a chance
in the lower elevations as well. There is some uncertainty still
with the path of this low, with the GFS and ECMWF bringing the low
up the coast of Oregon and Washington, while the NAM brings it
inland over northern California. None of the QPF amounts look to
be all that much and snow amounts with the next system look light
as well. Snow levels will quite high today. This morning, they
will initially be 5000-6000 feet across the Washington Cascades
and Wallowas and 6500-7500 feet elsewhere. By afternoon,
everywhere should be over 7000 feet. Snow levels will remain
between 5500 and 6500 feet on Friday but will begin to fall on
Saturday as the next system approaches. Snow levels will mainly be
between 4500 and 5000 feet by Saturday morning and 3500 to 4000
by Sunday morning.

Confidence continues to be high (70-90%) for gusty winds across
the Blue Mountain foothills through this evening and potentially
even into Friday. However, confidence is lower (50%) as to exactly
how high winds will get. Latest model suite has come in a bit
lower for winds with NBM (and even NBM 4.1) and ECMWF backing off
their initial numbers. Just for comparison, 24 hours ago, roughly
90% of the ECMWF ensemble members indicated wind gusts of 45 mph
or more at MEH and now its about 66%. At ALW, the current number
of ensemble members with wind gusts of 45 mph or more is roughly
20%. GFS guidance has much lower guidance, with wind gusts in the
20s and seems too low. The ECMWF EFI keys in on wind speed for
today across the Oregon Blue Mountain foothills, with an area
between 0.7 and 0.8, and a smaller region of 0.8 to 0.9.
Interestingly, it is not highlighting wind gusts.

The guidance also suggest that the winds could remain gusty into
tonight and Friday afternoon, with another peak possibly later
tonight. For now, will not extend the headlines due to the lagging
confidence as mentioned above.

High temperatures are going to be above normal through the
the period, in many cases 5 to 10 degrees, above normal. There is
high confidence (80-90%) of this occurring. High temperatures will
mainly be in the 50s today through Saturday, with 40s, in
portions of the Columbia Basin, Gorge and colder valleys.
Overnight lows will mainly be in the 30s and 40s. In fact, in
some areas, the lows will be not too far from what the normal
highs should be heading into mid-January. The ECMWF EFI highlight
some of these areas with0.6 to 0.7 for highs across mainly the
Blue Mountain foothills today and Friday. However, for the lows,
there is a much larger area of 0.6 to 0.7 tonight and a smaller
area 0f 0.7 to 0.8 along the foothills. Friday night, sees
virtually all of eastern Oregon and much of eastern Washington in
0.8 to 0.9 and some locations of 0.9 to 0.95. Virtually all
(~100%) of the ECMWF and GFS ensemble members have a high 50
degrees or higher on Friday at PDT. At PSC, its about 20% of the
GFS ensemble members and 33% of the ECMWF. At RDM, its almost all
ECMWF ensemble members (~100%) but about 50% of GFS ensemble
members.

.LONG TERM...
Sunday through Thursday...Not much has changed in the
guidance over the last 24 hours. Pattern remains progressive with a
series of troughs swinging through the West Coast, with the bulk of
the moisture falling to our south as conditions are kept
unseasonably mild for mid-January. SW flow aloft will keep this
relatively warm air mass in place through at least the next week,
with some slight chance PoPs in the mountains as a result of the
weak moisture advection favored by the synoptic pattern, but still
not anticipating any impactful precipitation to occur until a more
organized low is forecasted to arrive in our area sometime around
the Tuesday to Wednesday timeframe. The active, progressive nature
of the synoptic pattern has resulted in great disparities across
ensemble members as far as timing is concerned, but guidance remains
in good agreement on the overall SW pattern and above-normal
temperatures forecasted through the period.

Snow levels will begin to dip toward the 2000-3000 ft range by
midweek next week as the aforementioned more-organized low looks to
pull in cooler, more northerly air into the PacNW, but overall
expectation is that our lower elevation areas and population centers
will be free of wintry precip concerns given the unseasonably warm
conditions we've experienced over the past week. Only real concern
would be in the Kittitas Valley and central OR, but even then early
QPF ensemble guidance isn't suggesting anything significant as of
now. This, of course, could change as models better converge on the
strength of this mid-week system, but still expecting wintry impacts
to mostly be isolated to our mountain zones. Otherwise, messaging
remains consistent in that mild conditions are expected for our
area, with temps in the 40s to low 50s across our population
centers, with only light precip impacts anticipated, primarily for
our mountain zones, until that mid-week system brings the threat for
more area-wide precipitation. Evans/74

&&

.AVIATION...
12z TAFs...Light rain will impact most sites through the
day today. While shower intensity is expected to be on the lighter
end, MVFR to even locally IFR conditions are possible through the
course of the day Thursday. Showers may let up at times during the
day, but MVFR cigs will likely prevail even under drier conditions.
Rain is expected to end by around sunset, leaving low clouds through
Thursday evening, cigs less than 5 kft for most sites. BDN/RDM
expected to remain mostly dry with south winds 10-15 kts. PDT/ALW
could see breezy downsloping winds off the mountains Thursday
afternoon, but confidence is low. Evans/74

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  55  44  54  41 /  70  10  10  10
ALW  55  44  52  41 /  70  10  10  10
PSC  45  37  47  38 /  70  20  10  10
YKM  40  34  42  32 /  60  60  20  30
HRI  50  40  50  38 /  60  10  10  10
ELN  39  34  40  32 /  60  70  30  30
RDM  52  42  52  36 /  30  10  10  20
LGD  43  39  45  36 /  70  10  10  10
GCD  48  38  47  35 /  50   0  10  10
DLS  46  42  48  40 /  60  50  40  60

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 7 PM PST this evening for ORZ049-508.

     High Wind Warning until 7 PM PST this evening for ORZ507.

WA...Wind Advisory until 7 PM PST this evening for WAZ029.

&&

SHORT TERM...77
LONG TERM....74
AVIATION...74