Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 072243
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
243 PM PST Sun Mar 7 2021

Updated aviation discussion

.SHORT TERM...TONIGHT THROUGH TUESDAY...An upper level trough off
the coast will continue to influence the regional weather by
inducing periods of showery weather. At the heart of the trough is a
closed low pressure currently off the coast of Canada. This low will
slowly drop southward and be along the Oregon coast by Tuesday. In
doing so it will send some occasional impulses across the forecast
area under a southwest flow aloft. It will also increase shallow
Spring time instability helping enhance shower activity during the
afternoons. Snow levels will range from 2000 to 3000 feet but
occasional dip lower in the overnight periods. However, the showery
nature of the precipitation means that snow accumulations will be
spotty and will quickly melt.

One of those impulses will arrive early Monday and spread some
light showery precipitation mainly across central and eastern
Oregon. Some of this could be snow showers producing some light
accumulations which is expected to melt quickly once the sun is up.
This will be followed by increasing shallow instability midday and
afternoon producing more convective showers. These showers will
begin to decrease around sunset with most ending by midnight with
possible exception of far eastern mountains. Showers will then
return on Tuesday midday and afternoon as the heating of the day
induces the shallow instability which in turn develops into
showers. These showers to will begin to fade out around and after
sunset Tuesday.

.LONG TERM...WEDNESDAY THROUGH SUNDAY...The upper level low off the
Oregon Coast will eventually drop down into California on Wednesday.
This will push the upper level trough across the region for one last
day of cool showery weather. The trough will exit to the east on
Thursday with just a few lingering showers over the eastern
mountains. Meanwhile, an upper level ridge will build into and over
the region Thursday through Saturday for a stretch of warmer and dry
weather. A high degree of model uncertainty begins going into next
weekend. The GFS wants to begin breaking down the ridge and have the
next upper level trough arriving late Saturday into Sunday with
possible precipitation. However, the ECMWF wants to hold the ridge
in position over the region through Saturday and then just flatten
the ridge on Sunday but stay dry. Opted to keep a dry forecast
through Saturday and then introduce just a slight chance of showers
on Sunday.

&&

.AVIATION...00Z TAFs...VFR conditions will continue for all location
with the possible exception of BDN and RDM where some rain/snow
showers will become possible Monday locally reducing VSBYs and CIGS
to possible MVFR to IFR briefly. 10-20kts winds will drop to less 10
kts after sunset.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  34  44  31  51 /  10  30  10  20
ALW  35  47  33  53 /  10  30  10  20
PSC  36  50  33  55 /   0  10   0  10
YKM  31  49  29  51 /   0  10  10  10
HRI  35  49  31  55 /  10  20  10  10
ELN  28  47  28  46 /   0  10  10  20
RDM  27  46  25  48 /  20  20  20  20
LGD  30  40  26  42 /  20  50  20  20
GCD  31  44  27  44 /  20  40  20  20
DLS  35  49  34  51 /   0  20  20  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

$$

SHORT TERM...91
LONG TERM....91
AVIATION...91



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