Area Forecast Discussion
Issued by NWS Pendleton, OR

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491
FXUS66 KPDT 200539 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1030 PM PDT Sat Oct 19 2019

updated the aviation discussion

.UPDATE...A weather system was slowly moving away from the
region and pressure gradients were decreasing across the area and so
were the winds.

Meanwhile a nw upslope flow was pounding the blue mountains with
over ten inches of snow at elevations above 5k feet where winter
storm warnings remain in effect. The latest radar was continuing
to show pcpn falling over this region and further east into the
Wallowas. Elsewhere the wa/or crest was also receiving rain and
snow showers.

As the pcpn decreases overnight from west to east...another
weather system will push into the pacnw tomorrow and showers are
expected.

Otherwise minor changes were done to pops and sky and temps that
are forecast to fall into the 30s and 40s tonight.

&&

AVIATION...A weather system was moving away from the area and
mainly vfr conditions can be expected. Another weather system
approaches the region tomorrow and lcl mvfr conditions may develop
at taf sites kdls...kykm...krdm...kbdn after 15z especially in
showers. As the system moves east taf sites kpdt...kpsc and kalw may
experience lcl mvfr conditions after 18z.

&&

.PREV DISCUSSION... /issued 510 PM PDT Sat Oct 19 2019/

SHORT TERM...Expect showers to continue through this evening
with steady upslope rain/snow continuing in the mountains in the
moist, upslope northwest flow. Moderate to heavy snow expected
over the northern Blues and in Wallowa county above 4500-5000ft.
Breezy to windy conditions continue behind the front as surface
gradients tighten and strong 850 winds mix down. Strongest winds
over central to northeast OR. Improving conditions tonight as the
disturbance kicks east, but a few mountain snow showers will
continue.

Sunday through Monday night will still see moist, northwest flow
aloft with a couple of weaker shortwaves traversing the region. A
warm front will bring an increasing chance of rain and mountain
snow on Sunday with snow levels around 4500 feet over eastern
OR/WA sloping upwards to 6000-7000 feet over central OR.
Precipitation amounts will be light, but there will likely be 1-3
inches of new snow over the eastern mountains. Another front will
pass overhead on Monday, but precip likely relegated to the
mountains with only the highest peaks seeing snow. Localized
breezy winds still possible Sunday into Monday, mainly on the
peaks.

Moderating temps through the period with highs today in the 40s
to mid 50s, climbing to the 50s to lower 60s by Monday. Lows
tonight in the upper 20s to low 40s, rising the the mid 30s to
upper 40s by Monday night.

LONG TERM...Tuesday through Saturday...Models in good agreement
through Thursday, but then begin to diverge thereafter.  Northwest
flow aloft will continue into Tuesday resulting in a chance of
showers along the Cascade crest as well as the Blue Mountains. These
showers will decrease Tuesday night as an upper level ridge builds
over the eastern Pacific.  The upper ridge will be pushed southward
as the next system moves out of the Gulf of Alaska by Friday. There
are some discrepancies in how the GFS and ECMWF handle this system.
The GFS keeps much of the energy over BC while the ECMWF pushes into
Washington.  At this time, will lean more towards the drier GFS.
However, there could be some light rain Friday night over the
Washington Cascades. Temperatures will remain near normal through
the period.  Earle

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  39  55  44  61 /  30  40  20  20
ALW  41  56  46  61 /  80  50  40  30
PSC  43  58  47  62 /  10  40  10  10
YKM  34  55  39  60 /   0  60  10  30
HRI  42  59  47  63 /  10  40  10  10
ELN  35  50  37  55 /  20  60  20  40
RDM  31  55  35  62 /  20  30  10  10
LGD  35  47  38  53 /  60  50  50  30
GCD  34  50  37  57 /  50  50  30  10
DLS  44  54  46  59 /  20  50  20  30

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 4 AM PDT Sunday for ORZ502.

     Winter Weather Advisory until 4 AM PDT Sunday for ORZ050.

WA...Winter Storm Warning until 4 AM PDT Sunday for WAZ030.

&&

$$

97/97/



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