Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 202037

Area Forecast Discussion
National Weather Service Pendleton OR
137 PM PDT Fri Sep 20 2019

.SHORT TERM...Rest of today through Monday...Northerly flow
continues to result in a few upslope showers over the 
Blue/Wallowa Mountains. Expect coverage to continue to decrease 
through the evening before ending overnight. Upper level ridge 
will set up overhead for Saturday with partly cloudy skies and 
temperatures warming into the middle to upper 70s across the 
Columbia Basin with 60s for the mountains. Next system arrives 
Sunday with showers arriving along the Cascades near dawn then 
gradually spreading east through the forecast area by the early 
afternoon. Rain amounts will be highest in the mountains ranging 
from 0.1-0.3" with amounts of only a few hundreths of an inch 
expected across the Columbia Basin. Any lingering showers 
associated with the frontal boundary end before sunrise Monday 
with a more westerly, mainly dry, flow pattern setting up for 
early next week. Richards

.LONG TERM...Monday night through Friday...Models in fairly good 
agreement through mid-week. Short-wave ridging shifts south and east 
Monday night as the region falls under fast northwest flow aloft. 
Expect drier conditions through mid-week. However there will be 
variable cloud cover and possible mountain showers, especially over 
the WA Cascades, as Pacific moisture and a couple of quick moving 
fronts try to clip the region. Models differ a bit for late week, 
but there is increasing confidence for a strong cold front to swing 
through on Wednesday night or Thursday, followed by a deepening 
upper-level low dropping south and setting up over the western US 
Thursday night into Friday. Expect a good chance of showers for the 
region, but overall model spread and run-to-run variability in the 
upper-low strength, timing and location make it difficult to nail 
down any high end probabilities nearly a week out. Mountain snow a 
strong possibility for late week as freezing levels expected to drop 
significantly. Some breezy to windy conditions possible as stronger 
winds aloft mix down with each frontal passages, especially Tuesday. 
Seasonal temps expected through mid-week with highs in the 60s to 
mid 70s. Well below normal temps expected Thursday and Friday.


.AVIATION...00Z TAFs...Mountain showers still possible through
evening. Mainly VFR conditions expected. SCT-BKN at 040-080 with BKN 
mid and high clouds will decrease and transition to just high clouds 
later this evening. Winds generally 10kts or less through the 
period, but a bit stronger at DLS 12-16g20-24kts through evening. 
Just a few high cirrus tomorrow with lighter winds.


PDT  48  74  50  72 /   0   0   0  30 
ALW  52  76  54  76 /   0   0   0  30 
PSC  53  78  54  76 /   0   0   0  30 
YKM  47  76  49  71 /   0   0   0  50 
HRI  51  78  52  75 /   0   0   0  30 
ELN  48  75  50  69 /   0   0   0  60 
RDM  41  73  45  67 /   0   0   0  60 
LGD  43  70  47  72 /  10   0   0  40 
GCD  43  71  47  71 /  10   0   0  40 
DLS  53  76  55  71 /   0   0   0  60