937 
FXUS66 KPDT 210337
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
837 PM PDT Fri Aug 20 2021

.UPDATE...Showers and thunderstorms continue across the eastern 
mountains of Oregon and Washington as the cold front pushes east
of our forecast area. The main activity is now pushing northeast
into the Idaho Panhandle region, and north into north-central
Washington. As such, have reduced PoPs across the Yakima and 
Kittitas Valleys in the near term, and made slight adjustments to 
sky cover across central Oregon based on satellite imagery.
Otherwise, no major changes to the forecast. 86/88

&&

.PREV DISCUSSION... /issued 440 PM PDT Fri Aug 20 2021/ 

AVIATION...00z TAFs...Main impacts continue to be smoke and haze,
primarily over YKM/PSC/PDT/ALW. Conditions could be IFR at times 
at YKM. There will be some mid and high-level clouds today and 
overnight and some possible thunderstorms in the vicinity of 
YKM/PDT/ALW, but not included in TAFs at this point as most
activity is expected to be in the mountains. Winds expected to be
5-15kts. 86

PREV DISCUSSION... /issued 121 PM PDT Fri Aug 20 2021/ 

SHORT TERM...Today through Sunday...An upper low approaches the
region and will move across through the early weekend. This low
brings with it chances of precipitation along with a risk of some
storms possible, primarily near Kittitas County as well as Wallowa
County in our CWA. The lightning potential remains low enough that
it precludes a risk of fire initiation at this time. Further into
the borders of WA and OR, the chances of precipitation decline, 
but a slight chance at some rain could occur as this low moves 
through. Also with the low, breezy winds are expected.

The low continues eastward into Sunday, with another low expected
to move across southern BC Sunday into Monday. The low will remain
north of our region with no precipitation activity expected out of
it, but will tighten the pressure gradient and promote widespread
gusty westerly winds. The combination of these features are 
expected to keep our high temperatures below average over the next
several days, with 70's into the mid 80's expected through the 
weekend.

Finally of note, smoke models continue to indicate little in the
way of respite from the ongoing haze and localized smoke. Have
reflected this in the forecast with haze nearly all weekend as
models show drifting smoke across the region, but there is the
chance precipitation may aid in wildfire issues. Goatley/87

LONG TERM...Monday through Friday...An upper level closed low will 
be over southwest Canada on Monday with the Pacific Northwest being 
under the influence of a slightly cyclonic flow. This will be a dry 
pattern with some locally breezy areas and temperatures slightly 
below normal. The low moves off into central Canada on Tuesday which 
allows a continued westerly flow across the forecast area Tuesday 
through Friday. There will be impulses passing to the north through 
Canada with some occasional weak trough passages impacting the 
Pacific Northwest generating some periods of locally breezy 
conditions. Temperatures will remain around normal during this time 
with no precipitation expected. 

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  51  74  49  80 /  30  20   0   0 
ALW  55  77  55  82 /  40  30   0   0 
PSC  59  80  58  83 /  20  20   0   0 
YKM  56  79  51  81 /  20  20   0   0 
HRI  56  79  56  82 /  20  20   0   0 
ELN  56  77  53  75 /  40  30   0   0 
RDM  43  72  41  80 /  10  10   0   0 
LGD  50  71  47  81 /  60  50  10   0 
GCD  48  75  46  85 /  30  20   0   0 
DLS  58  79  57  79 /  10  10   0   0 

&&

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

$$

SHORT TERM...86/88
LONG TERM....91
AVIATION...86