157 
FXUS66 KPDT 211349 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
737 AM PDT Sat Aug 21 2021

updated the aviation discussion 

.SHORT TERM...Saturday through Monday...The axis of an upper-level 
low will swing through the forecast area today, bringing another 
chance of showers and storms primarily for the eastern mountains, 
however a slight chance exists for the Yakima and Kittitas Valleys 
as well. CAMs showing a sufficient amount of lift and moisture along 
the eastern mountains as the upper-level low taps into moist Pacific 
air, providing the area with more much-needed rain. Expecting the 
bulk of any precip to occur in Wallowa County, with the HREF 
depicting on and off spotty shower coverage over the area. HREF also 
shows just enough MUCAPE for isolated storms, however current 
thinking is that best chance for storms exists north and east of the 
CWA, with the atmosphere too moisture-laden to justify any fire 
weather headlines.

For the Yakima and Kittitas Valleys, there's consistent portrayal of 
spotty showers in the HREF for the area through late afternoon 
Saturday, however models have included the overnight hours tonight 
for chances of showers, which have thus far only materialized well 
to the north. Models show sufficient instability and mid-level 
moisture for precip, however with the back end of the low passing 
through later in the day, thinking that drier, northwesterly flow 
will dominate and make PoPs pretty limited, however will keep slight 
chance in for the area given cross-model agreement on at least 
isolated showers.

Sunday and Monday expected to be dry as the trough moves to our east 
and more zonal flow dominates. Skies will clear and RHs will drop in 
light of dry westerly flow, however temps expected to remain 
relatively mild, keeping fire weather concerns above critical. Haze 
and smoke look to persist through much of the weekend, especially in 
the Yakima Valley with the ongoing Schneider Springs fire, however 
westerly flow should push a decent amount of haze/smoke to the east, 
allowing for some clearing heading into Monday. 74

.LONG TERM...Tuesday through Saturday...A weak ridge of high 
pressure on Tuesday is forecast to push east with a trough of low 
pressure expected to track across the two state area Wednesday. This 
should bring an increase in clouds mainly over our WA zones that 
could also produce a few showers along and near the crest. The 
trough may tighten pressure gradients creating breezy conditions for 
the area Wed/Thur. The F1 variance were in good agreement with the 
timing and strength of the systems forecast through the week with 
moderate to high confidence. The trough moves away from the two 
state area Friday as a high pressure system builds into the pacnw 
into Saturday with a warming trend expected. 


&&

.AVIATION...lcl mvfr conditions expected at taf site 
kykm in smoke Saturday. Otherwise most other taf sites should 
experience mostly vfr conditions through the period while taf site 
kalw may experience vicinity showers through 16z.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  75  53  79  46 /  20   0   0   0 
ALW  76  57  81  50 /  40   0   0   0 
PSC  79  59  83  51 /  10   0   0   0 
YKM  79  54  80  46 /  30   0   0   0 
HRI  79  57  82  49 /  10   0   0   0 
ELN  76  55  74  47 /  40   0   0   0 
RDM  73  41  79  39 /   0   0   0   0 
LGD  67  48  81  44 /  50  10   0   0 
GCD  71  47  85  45 /  20  10   0   0 
DLS  78  58  78  50 /  10   0   0   0 

&&

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

$$

SHORT TERM...74
LONG TERM....97
AVIATION...97