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622
FXUS66 KPDT 261524
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
824 AM PDT Sat May 26 2018

.SHORT TERM...Upper level low pressure continues to move
slowly eastward across the Great Basin, with a weak surface
trough/frontal boundary across NE Oregon producing scattered
to numerous showers across mainly the higher elevations. The upper
low will continue to move gradually east to the eastern portions
of the Great Basin by Sunday. With the mid/upper level forcing
decreasing across the local area, precip coverage will decrease
this afternoon/evening, with all precip to the east by the late
evening hours. With some residual instability across Wallows
county this afternoon, an isolated thunderstorm or two will be
possible. Do not expect strong/severe storms as deep layer shear
will be minimal where the instability is present, with rainfall
rates lower than yesterday. With a rather tight surface pressure
gradient field, breezy to windy conditions will prevail across the
Columbia Basin/Gorge as well as the Kittitas Valley through this
evening. Cool high temperatures in the upper 60s to mid 70s can be
expected for the lower elevations today.

&&

.AVIATION...12Z TAFS...VFR conditions will occur for the next 24
hours. Skies will clear from the west over KDLS, KYKM, KRDM and
KBDN, then by late morning and afternoon at KPSC, KPDT and KALW.
Otherwise, winds will be breezy at times, especially at KDLS.
Light rain showers will continue over the Blue Mountains southward
across Grant County this morning and into this afternoon and then
taper off and end by 01Z.


&&

.PREV DISCUSSION... /issued 600 AM PDT Sat May 26 2018/

SHORT TERM...Today through Monday...An upper low pressure system
which brought strong to severe thunderstorms, and showers with
abundant rainfall in some areas to northeast Oregon is moving out
and the precipitation is rapidly decreasing at this time. Will let
the flood products expire at 5 AM as scheduled. High pressure ridge
aloft will begin to build into the Pacific Northwest beginning later
today and on Sunday and continue into Monday. This will bring back a
warming and drying trend to the CWA. There will be some remnant
instability and moisture over extreme northeast Oregon on Sunday,
but all areas will be dry on Monday. It will become breezy to windy
in open areas such as the eastern Columbia River Gorge, the Kittitas
Valley, the Lower Columbia Basin and possibly the Foothills of the
northern Blue Mountains. The upper ridge will continue into the
extended forecast period. Winds will become light on Sunday, but
then they will increase again in open areas on Monday...mainly in
the eastern Columbia River Gorge. Temperatures will rise back into
the 80s for Sunday in the Basin, and more widespread 80s in the
lower elevations on Monday. 88

LONG TERM...Monday night through Friday...A mid-upper level trough
arrives on the coast Tuesday afternoon spreading mid level moisture
into central Oregon for a chance of showers and a slight chance of
late afternoon and evening thunderstorms. The trough swings rapidly
through the forecast are Tuesday night and Wednesday morning thus
keeping a chance of showers over the lower Columbia Basin, the Blue
Mountain foothills and the eastern Oregon mountains. Trough remains
over the interior Pacific Northwest Wednesday night for a chance of
mountain showers in eastern Oregon. Friday another disturbance move
into the region, but this one will be dry.  Polan

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  72  47  79  54 /  20   0  10  10
ALW  74  48  79  54 /  20   0  10   0
PSC  78  48  83  55 /  10   0   0   0
YKM  77  48  83  56 /   0   0   0   0
HRI  76  48  82  54 /  10   0   0   0
ELN  72  47  81  53 /   0   0   0   0
RDM  65  36  76  43 /  10   0   0   0
LGD  65  44  74  48 /  40  10  10  10
GCD  64  42  74  48 /  50  10  10  10
DLS  70  50  82  56 /   0   0   0   0

&&

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

$$

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