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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 230343

Area Forecast Discussion
National Weather Service Pendleton OR
843 PM PDT Sun Sep 22 2019

.UPDATE...The latest radar was showing the showers slowly
decreasing with the higher concentration over the eastern forecast
area. Elsewhere showers were along the wa/or cascades. A long wave
trough responsible for the pcpn and isolated tsra earlier...was 
moving east of the area and the showers are expected to lessen 
overnight but linger over the area mountains. Minor changes were
done to sky and pops and temps that are forecast to fall into the
50s with 40s and some 30s in the higher elevations.


.PREV DISCUSSION... /issued 350 PM PDT Sun Sep 22 2019/ 

UPDATE...Isolated thunderstorms were developing over Grant county
and the models were suggesting some instability in this area along
with central Oregon and the blue mountains. Therefore the 
forecast for this evening was updated to reflect this.

PREV DISCUSSION... /issued 130 PM PDT Sun Sep 22 2019/ 

SHORT TERM...Tonight through Wednesday...A weakening cold front 
will move across the forecast area this evening and exit into Idaho 
by Monday morning. The front will produce some light precipitation 
across the forecast area generally on the order of a tenth of an 
inch or less. Following the frontal passage, the forecast area will 
be under a west to northwest flow. As a warm front passes to the 
north Monday night and Tuesday there will be some moisture passing 
through the region which could bring some light precipitation to the 
Washington Cascades, otherwise dry through Wednesday afternoon. This 
will also lead to some breezy conditions on Tuesday for the forecast 

LONG TERM...Wednesday night through Sunday...Models 
continue to remain in agreement with deep upper level trough 
arriving by the end of the week. A front will arrive by late 
Wednesday evening bringing slight chances for a few rain showers 
primarily across the higher elevations of the Blues & Wallowas. 
Behind the passage of this front expect breezy conditions Thursday 
for much of the Columbia Basin & through the Gorge as well as 
through the mountain gaps. Trough really starts to dig into the west 
coast by Friday and remains in place through the weekend. This will 
keep unsettled weather across the region with showers possible each 
day. As of now, greatest chances for precipitation look to be along 
the higher terrain of central and northeast Oregon; however, most 
locations will have slight chances for showers at any given time 
through the weekend. Unseasonably cold air will accompany this 
trough with snow levels dropping down to ~3500 feet by Sunday 
morning. While widespread snow is not expected, some minor 
accumulations are certainly possible across the highest elevations. 

AVIATION...00z TAFs...Band of showers and light rain will continue 
to move east through the region with all activity exiting to the 
east by 06z tonight. VFR conditions are expected for all TAF sites 
with ceilings gradually rising behind the passage of the frontal 
boundary. Richards


PDT  51  72  52  74 /  50   0   0   0 
ALW  54  72  55  77 /  60   0   0   0 
PSC  53  75  54  80 /  20   0   0   0 
YKM  45  72  48  76 /  10   0   0   0 
HRI  52  74  54  78 /  30   0   0   0 
ELN  48  66  50  70 /  10   0  10  10 
RDM  37  72  44  75 /  30   0   0   0 
LGD  47  69  49  71 /  70   0   0  10 
GCD  47  68  47  72 /  70   0   0  10 
DLS  48  71  53  75 /  10   0   0  10