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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 221710 AAA

Area Forecast Discussion...Updated
National Weather Service Pendleton OR
1010 AM PDT Sat Jun 22 2019

Updated aviation discussion

.SHORT TERM...Today and tonight...A flat ridge of high pressure is 
moving into the region bringing warmer temperatures today but also 
increasing westerly winds. Temperatures will be 5 to 10 degrees 
warmer today with westerly winds increasing along the east slopes of 
the Cascades which will spread out into the Columbia Basin this 
afternoon and evening before decreasing a little overnight. There 
will be some lingering moisture and very weak instability over 
Wallowa county from the departing weather system which will lead to 
a few showers mainly over the mountains. Temperatures will also be a 
little warmer overnight.  


.AVIATION...18Z TAFs...Skies will generally have scattered cirrus 
above 20K feet through the next 24 hours though the Columbia Basin 
sites KALW, KPDT and KPSC will have scattered clouds tonight around 
6K feet as clouds bank up against the Blue Mountains. A few showers 
will be possible over Wallowa county this afternoon. Winds will 
increase this afternoon with TAF sites having west to northwest 
winds of 10 to 20 kts with gusts to 30 kts before decreasing to 
below 12 kts around 06Z. Winds will begin increasing again after 15Z 
tomorrow morning. An exception will be KDLS which will have 
northwest winds of 15 to 25 kts with gusts to 35 kts for the next 24 
hours with only a slight decrease tonight. Perry


.PREV DISCUSSION... /issued 208 AM PDT Sat Jun 22 2019/ 

SHORT TERM...Today through Monday night. Satellite showing 
mainly clear skies across the forecast area early this morning. 
Upper ridge building into the Pacific northwest today with a 
northwest flow aloft. Expecting mostly sunny skies with warmer 
temperatures. Highs will be in the 70s to mid 80s. A weak 
disturbance moving through the ridge late today could bring a few 
showers to the Blues or Wallowa county. The flow aloft becomes 
more westerly on Sunday. Another mostly sunny day with 
temperatures a few degrees cooler. An upper low approaching the 
area on Monday will then turn the flow southwesterly. Some mid and
high level clouds moving through with partly cloudy skies. 
Surface gradients will continue to result in breezy westerly winds
each day especially along the Cascade east slopes into the 
Columbia basin. Sunday looks to be the strongest winds. 94

LONG TERM...Tuesday through Saturday...An active pattern is 
expected Tuesday through Thursday with southwesterly/southerly flow 
over the area along the eastern periphery of an upper level low 
offshore. Decent lapse rates will be in place over much of the 
eastern and central mountains of Eastern Oregon the big questions 
are how much surface based heating will occur, and what will the 
surface moisture fields look like. Based on current model solutions 
the best combination of these fields look like they'll remain mostly 
confined to Crook/Wheeler/Grant/Umatilla/Union and Wallowa County 
and have confined a slight chance of thunderstorms each afternoon. 
Given rather meager instability, even with some surface heating, do 
not have enough confidence to include thunderstorms for points 
further west, up to the Cascades at this time. Stronger flow 
associated with the aforementioned low will yield cloud layer shear 
60-80KTs Tuesday and Wednesday with some potential for a stronger 
storm or two should updrafts manage to avoid getting sheared off. 
Model and ensemble families begin to diverge significantly beyond 
Friday with eventual ejection of the low and will nudge to the blend 
beyond Friday. As flow turns more westerly in response to the 
exiting low should see some breezy 15-25 mph winds returning to the 
Cascade gaps. Peck


PDT  79  54  77  47 /   0   0   0   0 
ALW  81  56  78  50 /   0   0   0   0 
PSC  85  57  82  50 /   0   0   0   0 
YKM  82  53  78  46 /   0   0   0   0 
HRI  83  57  80  50 /   0   0   0   0 
ELN  74  56  70  47 /   0   0   0   0 
RDM  77  45  74  41 /   0   0   0   0 
LGD  74  48  71  43 /   0   0   0   0 
GCD  73  46  71  43 /   0   0   0   0 
DLS  76  58  73  51 /   0   0   0   0