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FXUS66 KPDT 241138 AAA

Area Forecast Discussion
National Weather Service Pendleton OR
300 AM PDT Wed May 24 2017


.SHORT TERM...Today through Friday...Water vapor imagery shows a 
trough moving into the area with an upper low moving southeast along 
the Canadian Rockies towards northern Washington. A cold front is 
just about ready to move into Idaho. The front is very moisture 
starved and there has been no precipitation and few if any clouds. 
The main impact is increased winds though some areas are having a 
lull during the overnight hours. Ellensburg airport continues to 
have northwesterly winds at 25 to 35 mph with gusts to 45 mph so 
current wind advisory for Kittitas county looks good. The rest of 
the area will have west to northwest 15 to 30 mph winds with gusts 
to 35 mph through this afternoon. Do not think winds will reach 
advisory levels elsewhere, though it could be close for a few hours 
this afternoon in the Columbia Gorge, Columbia Basin and Blue 
Mountain Foothills. The other main impact will be temperatures as 
high temperatures today will be around 20 degrees cooler than 
yesterday. Highs will be in the upper 60s to mid 70s with upper 50s 
to mid 60s in the mountains. Tonight the upper low will move rapidly 
east into Manitoba but the trough will remain over our area with a 
northwest flow. Models show some moisture moving in this evening and 
a slight chance of showers developing in the Washington Cascades and 
eastern Oregon mountains in the late night and Thursday morning 
hours. A wave and instability under the trough will create a slight 
chance of showers and thunderstorms Thursday afternoon in the 
Cascades and from the Blue Mountain 06Z TAFs...VFR conditions will 
prevail during the next 24 hours. The main concern will be 
increasing winds this evening...especially at 
KDLS...KPSC...KALW...KPDT and KYKM. Winds in these locations will 
increase to at least 10 to 20 mph but more likely 15 to 25 kts...but 
likely staying below wind advisory criteria. Further south KRDM and 
KBDN will see an increase in wind as well...but not as much as the 
stations over the northern two thirds of the area. 88Foothills and 
Ochoco-John Day Highlands eastward. Do not expect any strong or 
severe thunderstorms. Rain amounts will be light and just a few 
hundredths of an inch in general. Showers will taper off in 
northeast Oregon during the evening. The trough will drift slightly 
eastward Thursday night and Friday and an offshore ridge will begin 
to build ashore. There will still be a moist northerly flow over the 
eastern half of the area and there will be a slight chance of 
showers and thunderstorms Friday afternoon over the northern Blue 
mountains and Wallowa county while the rest of the area is dry. 
Temperatures Thursday will warm a couple of degrees to the lower to 
mid 70s with mainly 60s in the mountains. Friday will be in the mid 
70s to lower 80s with mid 60s to lower 70s in the mountains. Perry 

.LONG TERM...Friday night through Wednesday...GFS and EC models in 
good agreement. Both show upper level trof in ID with residual 
moisture and instability over the eastern mountains Friday evening. 
Upper level ridge builds over the area during the weekend with above 
normal temperatures and dry stable conditions.  A southwest flow 
will return enough moisture for the slight chance of thunderstorms 
again Monday afternoon and also Tuesday and Wednesday afternoons. 
Upper level ridge combined with weak surface pressure gradient will 
keep winds light through the period. About the only impacts will be 
the much above normal temperatures resulting in high level snowmelt 
and increase runoff into some of the streams coming off the 
Cascades. 79


.AVIATION...12Z TAFs...Wind will continue to be main factor in 
TAFs.  Upper level trof combined with moderate to strong pressure 
gradient at the surface will produce west winds with g20-30kts 
diminishing after 03z. Mid and high clouds rotating around the back 
side of the trof will begin to affect eastern TAF sites after 00z. 


PDT  67  44  67  46 /   0  10  20  20 
ALW  70  49  70  51 /  10  10  20  20 
PSC  74  47  75  49 /   0  10  10  10 
YKM  73  47  76  49 /   0  10  10  10 
HRI  72  46  72  47 /   0  10  10  10 
ELN  66  44  73  47 /   0  10  10  20 
RDM  69  34  70  38 /   0   0   0  10 
LGD  64  41  63  41 /  10  10  20  20 
GCD  68  39  67  42 /   0  10  20  20 
DLS  69  48  78  51 /  10   0  10  10 


WA...Wind Advisory until 10 PM PDT this evening for WAZ026.

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