Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 251019
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
219 AM PST Sun Feb 25 2018

.SHORT TERM...Strong upper low moving southeast along the BC coast
this morning. Satellite shows solid cloud cover out ahead of the
low moving across the Pacific northwest. This will continue through
the morning and into the afternoon with increasing coverage of
precipitation. Expecting mostly snow for the mid and higher
elevations with a mix of snow and rain at the lower elevations.
Strong onshore flow will result in heavy snow for the Cascades
with another area of significant snow over the northeast Oregon
mountains. Advisories will remain in effect through the day and
into the evening. Another concern will be gusty westerly winds.
Strong flow aloft will mix down creating windy conditions. Expect
20-40 mph winds for many locations late morning into the afternoon.
Precipitation and winds will diminish overnight with the upper
trough moving across the region. Colder temperatures likely with
lows in the teens and 20s. A break in the active weather pattern
Monday with partly cloudy skies. Very cold air aloft will likely
result in some instability cumulus during the day. The next weaker
system will be approaching Mon night with increasing clouds.
Should be another cold night with teens and 20s. Tuesday will be
mostly cloudy with a chance of snow and lower elevation rain/snow.
94

.LONG TERM...Tuesday night through Saturday.  Active winter
weather will continue through the extended period with the models in
overall agreement on major features through much of the period. West
to northwest flow will be over the area Tuesday night ahead of the
next system to move into the northwest on Wednesday with moisture
and some wind ahead of the cold front expected to move through
Wednesday night. The upper level low pressure area pivots down the
coast and into the region Thursday and Friday carving out a broad
area of low pressure across much of the Pacific Northwest that
remain through Saturday with some pieces of energy rotation around
the trough and with cold air aloft will be unstable with rain and
snow showers.  Snow levels will rise to near 2000 to 3000 feet
Wednesday ahead of the cold front and then snow level will lower and
remain near the surface through most of the week and into the
weekend. Temperatures will be near normal Wednesday and then cool
back to below normal levels through the rest of the period. 93

&&

.AVIATION...12Z Tafs.  Current VFR conditions will degrade as
the next round of rain/snow moves in reaching KYKM around 12z and
then spreading south to KDLS/KPSC/KALW/KPDT between 15-18z and then
KRDM/KBDN after 18z.  Cigs/vsby will be dropping to IFR/MVFR and
possibly to LIFR with the heaviest snow and wind. Winds will be on
the increase after 12z with southwest 20-25 kts with gusts 30-35
kts. Conditions will start improving from the north after 21z, but
IFR may be possible at KRDM and KBDN until 06z Monday. 93

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  25  40  22 /  60  40  10  10
ALW  47  27  42  26 /  60  40  10  10
PSC  49  26  46  26 /  30  20  10   0
YKM  47  20  44  23 /  40  20  10  10
HRI  48  26  45  25 /  30  20  10   0
ELN  42  20  42  23 /  50  20  10  10
RDM  43  17  36  11 /  80  80  20  10
LGD  37  21  34  14 /  90  70  20  10
GCD  39  21  32  11 /  70  80  20  10
DLS  45  26  46  27 /  80  60  10  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 7 AM this morning to 1 AM PST
     Monday for ORZ506.

     Winter Weather Advisory until 1 AM PST Monday for ORZ049-050-502-
     503-509.

WA...Winter Weather Advisory until 1 AM PST Monday for WAZ030.

     Winter Weather Advisory until 10 PM PST this evening for WAZ520.

&&

$$

94/93/93



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