065 
FXUS66 KPDT 262221
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
221 PM PST Tue Nov 26 2019

.SHORT TERM...Tonight through Thursday night...Strong, compact
crashing onshore near the OR/CA border by early evening and will 
slowly drift eastward through the next couple of days. Winds will 
pick up out of the south across central OR and then turn more 
easterly later this afternoon. Snow, moderate to heavy at times, 
will lift north into central OR this evening and then tonight 
spread north into north-central OR and east towards the the
Ochoco-John Day Highlands, Southern Blues and Wallowas. Up in 
Washington, north and east facing slopes of the Cascades and 
Simcoe Highlands will see a prolonged period east to northeast 
winds and upslope snow. Have issued a Winter Wx Adv for Simcoe 
Highlands. Not enough spatial coverage for WA Cascades zone for 
Adv at this time, but higher elevations, including White Pass, 
could see 6 to 12+ inches. Snow showers continue tomorrow and 
then slowly diminishes tomorrow night before ending on 
Thanksgiving as the low slowly kicks east and weakens. Snow 
amounts outside of WA Cascades will range from 4-10 inches 
central OR (higher in mountains) to less around an inch or less 
in the Lower Columbia Basin as drier air is channeled in from the 
north. In addition, breezy to windy conditions expected as a 
strong pressure gradient exists across the CWA. Strongest winds 
will develop tonight and continue through most of tomorrow from 
the north to northeast across WA zones down into north-central OR 
into the Bend/Redmond area. This will likely lead to areas of 
blowing and drifting snow that will greatly impact holiday travel.
Cooling trend begins tomorrow with highs in the mid 20s to near 40,
only climbing into the low 20s to mid 30s on Thanksgiving as the 
cold Canadian air dives south behind the departing system. 84

.LONG TERM...Friday through Sunday...As Friday begins, the region
will be just west of the longwave trough axis induced by the 
current coastal low/shortwave. Cold temperatures will prevail, 
particularly in the high desert of central and southern Oregon 
where single digits to teens are expected. Scattered cloud cover 
is likely to linger as moisture from the weakening low is slow to 
exit the region. Models are in modest agreement on the development
of a new jet streak and associated low off the Pac NW coast 
Friday into Saturday. This shifts the area to a southwest flow 
regime likely to promote a warming trend Saturday into Sunday. 
Though this system is considerably weaker than our current low and
there remains some model disagreement, precipitation is expected 
for many areas over the weekend. Areas of central Oregon may see 
snow showers while the potential exists for a snow/rain mix for 
parts of the Columbia Basin. 76

Sunday night through Tuesday...Models showing some variation in a
system to move through Sunday night with best area for 
precipitation along the mountains and central Oregon. Sunday night
and early Monday, cold air will remain in the Columbia Basin with
the warmer air moving in from the southwest. It appears that most
of the precipitation for this area will be over by that time, but
will need to be monitored for any possible freezing rain. Mainly 
dry then Monday night and Tuesday with models indicating a flat 
ridge. 93

&&

.AVIATION...00Z TAFs...IFR conditions with light snow/blowing 
snow and strong winds at BDN/RDM through the period. MVFR cigs 
with a mix of rain/snow at DLS with mainly VFR for other sites. 
Increasing winds through the evening with very windy conditions at
YKM/PSC from 06z through Wednesday. Winds will becoming southeast
to east 15- 20kt this evening and then turn north/northeast on 
Wednesday 20-30kts with higher gusts. 93


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  30  40  23  32 /  20  30  20  10 
ALW  28  40  24  34 /  10  20  10   0 
PSC  32  41  29  37 /  20  20  20   0 
YKM  26  38  22  35 /  30  30  40  10 
HRI  30  43  26  36 /  30  30  30  10 
ELN  24  35  19  34 /  30  30  40  10 
RDM  20  28  12  25 /  90  90  70  20 
LGD  27  36  23  33 /  50  60  20  10 
GCD  28  35  21  32 /  60  70  30  10 
DLS  31  37  25  35 /  60  60  50  20 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 4 AM PST Thursday for ORZ506-508-510.

     Winter Storm Warning until 4 AM PST Thursday for ORZ509-511.

WA...Winter Weather Advisory until 4 AM PST Thursday for WAZ521.

     Wind Advisory from 1 AM Wednesday to 1 AM PST Thursday for 
     WAZ026>028-521.

&&

$$

84/76/93/93