Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus66 kpdt 172239 

Area forecast discussion
National Weather Service Pendleton or
239 PM PST sun Feb 17 2019

Short term...tonight through Wednesday...a large trough remains
over most of the Continental U.S. This afternoon. An upper low is moving
south over northern California and Nevada and its influence over
our area is steadily decreasing. Another low pressure area in
southern Alberta is sending a cold northerly flow into the area.
Moisture is limited with the incoming Arctic air but radar is
showing some returns over the Columbia Basin and Blue Mountain
foothills. Am expecting isolated light snow showers mainly over
the Washington Cascades, Blue Mountain foothills and northeast
Oregon mountains but anywhere aside from the Washington Columbia
Basin and central Oregon could see a stray shower. Snow amounts
will be less than an inch. Snow showers will taper off tomorrow
morning and the area will get a break Monday afternoon through
Tuesday morning. The main story will be colder temperatures as
lows tonight will be in the teens and in the mid single digits to
mid teens Monday night. Tomorrow will have high temperatures
mainly in the 20s though central Oregon should reach the lower
30s. The next concern will be a system out of the Gulf of Alaska
arriving Tuesday afternoon and impacting the area through
Wednesday. The entire area will have snow with this system and
winter weather highlights appear probable Tuesday night and
Wednesday over the Blue Mountain foothills, Grande Ronde Valley
and Wallowa County (2-5 inches) and eastern Oregon mountains (4-9
inches). The rest of the area will get 1-3 inches. Future shifts
will have to monitor to see when the confidence is there for any
watches, advisories and warnings to be issued. With increased
cloud cover, lows Tuesday night will be in the 20s and highs
Wednesday will be in the mid 20s to mid 30s. Perry

Long term...Wednesday night through Sunday. Snow showers will
linger over the area Wednesday night as the upper level system
starts to move east. It will continue to be cold through the week,
but should be drier Thursday into Friday as a ridge of high pressure
moves through. Another low pressure system will be approaching the
area Friday night with a chance of light snow across the area
Saturday with a cold front Saturday night. The upper level trough
remains over the area Sunday with another low dropping down the
coast. This will turn the flow more zonal and keep some area just
east of the Cascades more shadowed from light snow but most area
will continue to see some periods of light snow. Temperatures will
remain below normal. 93


Aviation...00z tafs. IFR/LIFR low clouds and fog will continue
through the evening at PDT/alw/psc as band of low clouds continue
to move south over the area and bank up against the Blue
Mountains. Ykm will also see slight upslope flow with light snow
and MVFR conditions overnight. Northerly flow will continue on
Monday with some clouds banked along the foothills with MVFR at
alw/PDT and mainly VFR at other locations. 93


Preliminary point temps/pops...
PDT 16 26 11 30 / 30 10 0 20
alw 18 26 13 30 / 30 10 0 20
psc 17 26 15 29 / 10 0 0 20
ykm 20 28 15 30 / 20 10 0 20
hri 19 28 15 31 / 20 10 0 20
eln 15 27 11 30 / 20 10 10 30
rdm 18 33 16 36 / 10 10 10 20
lgd 16 27 11 31 / 30 10 0 30
gcd 19 29 14 33 / 10 10 10 20
dls 25 33 24 37 / 20 10 10 30


PDT watches/warnings/advisories...

National Weather Service Glossary of Abbreviations