Strong gradient winds through the Grande Ronde Valley produced gusts in excess of 60 mph at the La Grande Airport.
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The episode as NWS PDT wrote it up.
Strong gradient winds through the Grande Ronde Valley produced gusts in excess of 60 mph at the La Grande Airport.
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 Pendleton, OR wrote its last area forecast discussion before the first event at Dec 17, 8:07 AM PST, 1 hour 13 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
807 AM PST Tue Dec 17 2019
.UPDATE...A ridge of high pressure over the area today will shift
eastward followed by a shortwave trough on Wednesday. Following
the trough will be a fast and moist westerly flow that will bring
significant precipitation to the Cascades. In the near term the
main concern is patchy freezing fog. Still have the freezing fog
advisories going in several places until noon and will evaluate
in the coming hours to see if they can be let go. The wind
advisory in the Grande Ronde Valley is already verifying so will
keep it in place. Temperatures will remain cold today underneath
the stratus deck in the Columbia Basin if it does not break up.
Current forecast is on track and just made some minor adjustments
for this forecast package. 78
&&
.PREV DISCUSSION... /issued 325 AM PST Tue Dec 17 2019/
SHORT TERM...Today through Thursday night...A ridge of high
pressure will remain over the area through tonight. This will lead
to continued fog and stratus around the Lower Columbia Basin with
cold air trapped beneath the stratus. On Wednesday the ridge will
move to the east allowing a decaying upper level low to into the
Pacific Northwest followed by a wetter warm front on Thursday. This
will bring some light precipitation into the Cascades Wednesday and
begin spilling over onto the east slopes in the afternoon with
initial precipitation type as primarily snow. By evening and
overnight this light precipitation will spread across the rest of
the forecast area and be accompanied by some warmer air aloft
resulting in a transition to some wintery mixed precipitation across
north central Oregon and then spreading into the Lower Columbia
Basin of Washington overnight and early Thursday. Snow levels over
central and eastern Oregon will also be on the rise late Wednesday
night and Thursday. Cold air trapped along the east slopes of the
Washington Cascades will keep precip type as snow before changing
over to a wintery mix on Thursday or Thursday night. Travel along I-
90 between Ellensburg and Snoqualmie Pass will be most impacted by
this system with several inches of snow Wednesday night through
Thursday followed by some wintery mixed precipitation. By Thursday
night snow levels will be 3000 to 5000 feet with some travel over
the mountains still being impacted by snowfall.
LONG TERM...Friday through Tuesday...A warm front lifts through the
area during the day Friday, shifting best rain chances to far
northern portions of the forecast area as well as along the Cascade
crests. This lull in activity will be short lived as the main system
begins to move onshore by Saturday afternoon bringing additional
scattered to widespread rain and mountain snow. By Monday the system
will begin to weaken and break apart with only slight chances for
precipitation, mainly across the higher terrain of central and
northeast Oregon. Snow levels through Saturday expected to remain
between 3500-5500 feet before dropping to near 1000-2500 feet by
Monday as the system exits. At this time, the area looks to be dry
heading into the Christmas holiday, but will need to keep an eye on
a potential system off the coast. Temperatures through Saturday will
be rather warm for this time of year with afternoon highs climbing
into the low to mid 50s for central Oregon into the lower Columbia
Basin. As the main front pushes east of the region Sunday through
Tuesday, we will see high temperatures return to normal with mid 30s
to lower 40s expected. Richards
AVIATION...12z Tafs. Dense fog/freezing fog will continue to impact
both KPDT & KALW with lifr conditions expected and visibilities of
1/4 SM. Patchy fog will also impact KYKM, but visibilities should
generally remain above 1 1/2 SM. Fog will gradually lift into a low
stratus deck this afternoon and evening before patchy dense freezing
fog becomes possible again overnight, possibly affecting PDT, ALW,
and YKM. KBDN/KRDM are expected to maintain vfr conditions through
the period. Richards
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 33 27 33 32 / 0 0 0 50
ALW 35 27 32 31 / 0 0 0 50
PSC 33 28 32 30 / 0 0 10 50
YKM 35 24 31 26 / 0 0 20 60
HRI 32 28 32 30 / 0 0 0 50
ELN 35 23 32 23 / 0 10 20 70
RDM 38 25 42 31 / 0 0 20 60
LGD 34 25 35 29 / 0 0 0 50
GCD 33 26 37 30 / 0 0 10 50
DLS 36 29 36 34 / 0 0 20 80
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Freezing Fog Advisory until noon PST today for ORZ044-507.
Wind Advisory until 4 AM PST Wednesday for ORZ049.
WA...Freezing Fog Advisory until noon PST today for WAZ026-027-029.
&&
78The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
Peak wind gust measured at La Grande AWOS.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2019Every state in 2019This day in weather historyWarnings in Oregon, December 2019
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: 868053.