Scientific Forecaster Discussion
fxus66 kpdt 142052
Area forecast discussion
National Weather Service Pendleton or
152 PM PDT Mon Oct 14 2019
Short term...tonight through Thursday...weak high pressure will
bring dry and stable conditions for the next 24 hours. It will be
another clear and chilly night, and Tuesday will be about 5-10
degrees warmer than today. A strong low level inversion will be
hard to break, and some of the valleys and lowest elevations will
struggle to see the warming on Tuesday until late afternoon...if
at all. Clouds will increase Tuesday ahead of a Pacific front
with skies mostly cloudy west and partly cloudy east in the
afternoon. The thickening altostratus/altocumulus clouds on
Tuesday may squeeze out sprinkles or a light shower over south
central and southeast Washington in the afternoon.
The front will gradually move onshore Wednesday morning.
Precipitation ahead of the front will spread to the Cascade crest
Wednesday morning then as far east as Hanford, Arlington, Condon,
and Prineville Wednesday afternoon. The eastern half of the
forecast area will not observe precipitation until Wednesday
evening when the leading edge of the front makes it way east of
the Cascades. The front will remain over eastern Washington/or for most of
Wednesday night then finally exit the region Thursday morning.
Based on the north-south orientation of the front and lack of
upper level support, there are no major concerns for Wednesday
and Wednesday night. Most elevations will observe light rain (snow
above 7000 feet) and it will be breezy in some areas, but nothing
to warrant highlights.
A westerly flow will follow on Thursday, and surface high pressure
building behind the system will cause a relatively tight pressure
gradient with 15-25 mph sustained winds in many areas. A moist
westerly flow aloft will keep scattered to numerous showers over
the mountains and isolated to scattered showers elsewhere. Snow
levels will lower to around 5500 feet. Wister
Long term...Thursday night through Monday. Active weather pattern
for the Pacific northwest. Strong westerly flow will push several
upper level troughs and associated fronts through the region.
Satellite showing a good moisture feed across the Pacific as
well. This will result in periods of rain with higher elevation
snow mostly above 4-5k feet. The Cascades will receive fairly
heavy precipitation through the period with current forecasts
indicating 2-4 inches of rainfall with significant snowfall
accumulations likely above 5k feet. Downslope flow will bring
limited rainfall to the Columbia Basin with another upslope Max of
precipitation for The Blues. Models have been consistent in
showing the Saturday and Sunday systems being fairly strong with a
140kt northwest jet providing good dynamics. Frontal passages and
mixing down of winds aloft will bring breezy to locally windy
conditions at times.
Aviation...00z tafs. Mid and high level clouds for the next 24
hours. Sct-bkn 150-250. Winds 5-10kt.
Preliminary point temps/pops...
PDT 38 64 44 66 / 0 0 0 10
alw 41 64 48 68 / 0 0 0 10
psc 40 63 45 65 / 0 10 0 10
ykm 37 60 40 60 / 0 10 10 40
hri 39 63 44 65 / 0 0 0 10
eln 36 59 40 58 / 0 10 20 40
rdm 35 70 42 65 / 0 0 0 40
lgd 37 66 45 68 / 0 0 0 10
gcd 39 70 47 68 / 0 0 0 10
dls 42 62 47 60 / 0 0 0 50