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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 181525

Area Forecast Discussion
National Weather Service Pendleton OR
825 AM PDT Thu Apr 18 2019

.SHORT TERM...Today and tonight...A ridge of high pressure will 
remain over the region with a southwest flow bringing some moisture 
into the Washington Cascades. There will be a few showers along the 
Washington Cascade crest but remain dry across the rest of the 
forecast area. Some mid and high clouds will filter over the region 
and temperatures will be warmer today being in the 60s and 70s with 
light winds.

AVIATION...18Z TAFs...Clear to partly cloudy skies today. Mid to 
high clouds increasing overnight into tomorrow morning and could see 
a few showers over the mountains, but dry weather at terminals. 
Winds around 5-10kts.


.PREV DISCUSSION... /issued 239 AM PDT Thu Apr 18 2019/ 

SHORT TERM...Today through Saturday night. Upper level ridge over
the area today with mostly sunny skies and much warmer temperatures.
Satellite indicates some cirrus will be moving through at times.
Highs in the 70s. The ridge will start to weaken tonight as a
system approaches the Pacific northwest. Clouds will be increasing.
An upper level trough will push a cold front through the region
Friday with rain likely and cooler temps. Most of the rainfall 
will be in the afternoon and evening. There is a slight chance of 
thunderstorms over the northeast Oregon mountains late. The front 
is slow to move out of the region and rain will linger into Friday
night over the southeastern portion of the forecast area. Upper 
level ridge builds in Saturday with clearing skies. 94

LONG TERM...Sunday through Thursday...Sunday should be a rather 
pleasant day with only partly cloudy skies and daytime highs 
slightly above normal. Will see a return to a slight chance of 
mountain showers Monday/Tuesday with moistening westerly flow, 
primarily in the Washington Cascades but could see a shower or two 
in the Blues and Oregon Cascades. A stronger system looks to arrive 
Wednesday afternoon in the form of a cold front with at least a 
slight chance of some lower elevation rain for much of the area with 
better precipitation chances limited to the Cascades and Blues. Both 
00Z GFS and EC should steepening of mid-level lapse rates ahead of 
the front with mixed layer CAPE in the 400-800J/kg range from 
southeastern Deschutes county northeast through southern Wallowa 
County. Will include a mention of slight chance for thunderstorms in 
this package although a quicker or slower FROPA than currently 
indicated would likely detract from this. Gradients along and behind 
the front will also at least breezy if not windy conditions with 
FROPA Wednesday afternoon/evening. Ensemble means suggest the front 
stalling along the southeastern edge of the CWA with some lingering 
showers possible Thursday. Peck


PDT  76  51  66  43 /   0   0  60  60 
ALW  77  53  66  46 /   0   0  70  50 
PSC  79  54  68  45 /   0   0  40  30 
YKM  75  51  67  40 /  10  10  40  10 
HRI  79  52  69  44 /   0   0  50  40 
ELN  70  48  59  38 /  10  20  40  10 
RDM  77  45  63  39 /   0   0  50  50 
LGD  71  45  65  42 /   0   0  80  60 
GCD  73  46  68  42 /   0   0  70  60 
DLS  77  51  64  44 /   0  10  40  20