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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 250336

Area Forecast Discussion
National Weather Service Pendleton OR
836 PM PDT Sat Aug 24 2019

.UPDATE...A weak disturbance moving near to the area was
tightening pressure gradients and creating breezy west winds. 
As the disturbance drifts away tonight the winds are expected to 
lessen. Meanwhile some mid and high level clouds were passing 
through the area and this should decrease as well and the forecast
was modified to reflect this. Also overnight low temps were 
adjusted and are expected to fall into the 50s with 40s in the 


.PREV DISCUSSION... /issued 420 PM PDT Sat Aug 24 2019/ 

SHORT TERM...Tonight through Monday night. Upper level trough and
strong jet moving across the Pacific northwest. Main impacts for 
today and this evening are breezy to locally windy conditions. 
These winds will diminish after sunset. Otherwise plenty of high 
level clouds evident on satellite with partly cloudy conditions 
expected tonight into Sunday morning. Upper ridge starts to build
back into the area later Sunday with clearing skies. The ridge 
becomes stronger Monday and Tuesday with warming temperatures and 
mainly clear skies. Locally breezy westerly winds Sunday then 
lighter Mon and Tue. 94

LONG TERM...Tuesday through Thursday Night...Models are in good 
agreement in having a ridge over the area Tuesday and Tuesday night 
with clear skies and fair weather expected. However, by Wednesday, 
models have a weak wave approaching from the southwest and shoving 
the ridge eastward. It also pulls subtropical moisture northward on 
a south to southwesterly flow. Wednesday afternoon and evening the 
front edge of the moisture is in central Oregon and the John-Day 
Ochoco Highlands. The moisture is at around 12-15 thousand feet and 
I do not see much instability, so have kept the forecast dry for 
now. Moisture drops to 5-10 thousand feet overnight and models start 
showing showers in the overnight period. Will take a wait and see 
approach on nocturnal showers but have added a slight chance of 
showers and thunderstorms in central Oregon and the eastern Oregon 
mountains Thursday afternoon and evening. The wave and most of the 
moisture is moving out of the area overnight Thursday night so have 
a dry forecast. Tuesday will have temperatures in the 80s and lower 
90s and Wednesday and Thursday will warm to the mid 80s to mid 90s. 
Winds will be light through the period. Perry

Friday through Saturday...Overall quiet pattern will persist across 
the region as broad southwest flow brings near to above normal 
temperatures in the upper 80s to lower 90s. Will need to watch a 
system for overnight Saturday into Sunday morning that may bring a 
few showers to the Washington Cascades, but most of this energy 
looks to impact areas north of the region. Richards

AVIATION...Mainly vfr conditions will persist. However brief 
gusty winds between 20 kts to 25 kts may develop at some taf sites
after 20z tomorrow. 


PDT  54  81  47  82 /   0   0   0   0 
ALW  58  83  52  85 /   0   0   0   0 
PSC  57  85  51  86 /   0   0   0   0 
YKM  52  84  47  86 /   0   0   0   0 
HRI  57  85  50  87 /   0   0   0   0 
ELN  55  77  47  84 /   0   0   0   0 
RDM  45  82  41  84 /   0   0   0   0 
LGD  51  77  43  80 /   0   0   0   0 
GCD  49  82  44  84 /   0   0   0   0 
DLS  57  82  52  88 /   0   0   0   0