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FXUS66 KPDT 240953

Area Forecast Discussion
National Weather Service Pendleton OR
253 AM PDT Sat Jun 24 2017

.SHORT TERM...Today through Monday...An upper level ridge will 
continue to slowly shift east into and over the Pacific Northwest 
today. This ridge will become centered over the region tonight, then 
continue to shift east on Sunday. As a result the region will be 
fair, dry and very warm to hot today and Sunday. Sunday will be the 
warmest day, as a thermally induced surface trough shifts east 
across the Cascade crest into the Interior Northwest by Sunday 
afternoon. High temps Sunday afternoon will be 15 to 20 degrees 
above seasonal. A southerly upper level flow will become 
established Sunday afternoon, as the upper ridge axis shifts east 
to extreme eastern Washington and Oregon. This south flow will allow 
moisture to move into the region. Instability due to the heating 
over the area will combine with the moisture to cause the 
development of a few thunderstorms over central Oregon Sunday 
evening. A few storms could linger into the early morning hours of 
Monday over central Oregon, otherwise will see clouds spread north 
and northeast across the Interior Northwest. An upper low currently 
centered near 31N/135W will weaken and move into the region Monday. 
This system will increase moisture and energy across the region. 
Thus isolated to scattered showers and thunderstorms will be 
possible over the area in the afternoon, mainly from central Oregon 
to northeast Oregon and extreme southeast Washington. Winds will 
increase through the Cascade gaps late Monday afternoon. High temps 
will be cooler than on Sunday over much of the area Monday afternoon 
due to increased cloud cover and the increasing influence of marine 
air. 90 

.LONG TERM...Monday night through Saturday...An upper trough will 
continue to move across eastern areas of the CWA Monday night and 
Tuesday. There will be enough instability and moisture to warrant 
the mention of evening showers and thunderstorms which will continue 
through most of the night Monday night...but will decrease after 
midnight. The upper trough will linger on Tuesday with a slight 
chance of showers and thunderstorms again in the far northeast 
portion of the CWA. Temperatures will cool down as the trough moves 
across the area and cooler marine air from the Pacific moves into 
the region. A northwest flow will develop behind the trough on 
Wednesday with a continuation of the cooler temperatures. High 
temperatures in the lower elevations will drop from the mid to upper 
90s on Monday to the 80s on Tuesday and Wednesday. This will be near 
normal on Tuesday and Wednesday. It will become breezy to windy 
Monday evening and again on Tuesday with this system. There may 
possibly be a need for wind highlights...mainly in the Kittitas 
Valley and the eastern Columbia River Gorge. From Thursday through 
Saturday an upper ridge will redevelop off the coast and keep a dry 
and stable northwest flow over the CWA. Temperatures will be on a 
warming trend once again...starting out in the 80s in the lower 
elevations on Thursday...warming to near 90 by Saturday. Winds will 
be light through that period. 88 


.AVIATION...12Z TAFs...VFR conditions with mostly clear skies and 
light winds will prevail through the next 24 hours. 88


.FIRE WEATHER...Previous Discussion...Hot and dry conditions this 
weekend will be followed by active thunderstorms in central and 
northeast Oregon and southeast Washington on Monday. Talking with 
neighboring land management agencies, the fine fuels such as grasses 
and shrubs in central and southeast Oregon have cured or almost 
cured. Therefore, any new lightning starts could result in rapid 
fire spread. Fire weather watches will be issued for Monday in fire 
weather zones 640 and 644 which covers the Prineville District, ODF 
John Day, and Heppner District. Thunderstorms in the Blue Mountains 
and Wallowa County will also produce abundant lightning, but the 
fuels are still green or showing signs of curing. Winds will also 
increase in the Eastern Columbia River Gorge and the Lower Columbia 
Basin on Monday and will become windy in some areas, but the 
humidities will also increase to around 18-28 percent. At this time, 
I will hold off on any watches but forecasters will monitor closely 
for changes that may warrant highlights. 


PDT  91  55  99  65 /   0   0   0   0 
ALW  91  61  99  70 /   0   0   0   0 
PSC  94  56 100  65 /   0   0   0   0 
YKM  94  57 100  67 /   0   0   0   0 
HRI  94  54 101  66 /   0   0   0   0 
ELN  94  55 100  65 /   0   0   0   0 
RDM  92  51  99  58 /   0   0   0  10 
LGD  86  49  94  57 /   0   0   0  10 
GCD  92  53  99  61 /   0   0   0  10 
DLS  99  58 102  69 /   0   0   0   0 


OR...Fire Weather Watch from Monday morning through Monday evening 
     for ORZ640-644.


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