449 
FXUS66 KPDT 020523 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1023 PM PDT Mon Aug 1 2022

...UPDATED AVIATION DISCUSSION...


.UPDATE/FIRE WEATHER...Smoke and debris clouds from thunderstorms
last night spread north across the forecast area today and played
a strong role in many of the sensible weather elements, including
temperatures, RHs, and thunderstorms--or lack thereof. It was 
cooler than we previously expected, and all of the Excessive Heat 
Warnings were cancelled earlier. Although there were scattered 
thunderstorms with significant CG lightning over south central OR,
storms have been isolated in our central OR zones. Thunderstorms 
did not materialize in northeast Oregon. The forecast was updated 
to remove the thunderstorm threat along the east slopes of the OR 
Cascades as well as the central Blue Mountains and Wallowa County.


Although not a strong onshore flow and marine push, cross Cascade
gradients have resulted in windy conditions through the eastern
Columbia River Gorge and the Kittitas Valley. These will continue
through the night, and the forecast will be updated to reflect
slightly stronger winds than currently in the forecast. A large
fire near Vantage will continue to experience gusty winds that
will be problematic for fire control. 

Weather concerns have also shifted into air quality, as the
McKinney fire near Yreka, CA has pushed a lot of smoke across the
forecast area. There is also a 41 acre fire near Crescent. Looking
at air quality monitors, central Oregon is not experiencing a 
significant deterioration in air quality but will be monitored.
Wister/85


&&


.PREV DISCUSSION... /issued 500 PM PDT Mon Aug 1 2022/ 

SHORT TERM... Tonight through Wednesday night...An area of low 
pressure off the coast will gradually move southward through 
midweek. Over the Pacific Northwest, there will mainly be a 
southwest that will become more westerly flow and northwesterly by
Wednesday and will tighten as well. 

Smoke from the McKinney Fire in northern California has been 
moving into our area, and once again today has helped suppress 
high temperatures. 

As a result, the excessive heat warning is being cancelled.
Temperatures will decrease a few degrees each day through 
midweek, and by Thursday it will feel downright pleasant! 

Models have been very consistent in developing afternoon
thunderstorm activity in southwestern and central Oregon today and
again on Tuesday. The majority of it remains south of our region,
but keys on Deschutes, Jefferson, and Crook Counties. One 
question is, if the smoke will suppress convective development as
well. 

There is decent instability, but the best CAPE is is over central
Oregon. Based on an overwhelming consensus in the models, have
backed off areal coverage of thunderstorms today and Tuesday.

The Red Flag Warnings currently in effect will remain unchanged. 
There could still be a few thunderstorms, mainly across central 
Oregon, though confidence in the rest of the region is low. 

Model guidance also does suggest increasing winds across the
Basin/Gorge/Kittitas Valley through Tuesday and then decreasing a
bit on Wednesday. 

The combination of winds and low RH values will bring red flag
conditions to the to these areas through Tuesday. Wednesday is
less cut and dry, as winds may decrease enough and RH may rise
enough that red flag conditions are not met, but obviously the
situation will continue to be monitored. With temperatures will
falling a bit each day, humidity values will slowly creep up.  

Today will be the warmest day of the next couple, but confidence
in high temperatures over the next few days is lower than average
due to smoke continuing to impact high temps. Overnight lows will
also become more comfortable.

LONG TERM...
Thursday through Monday...Ensemble guidance continues 
to keep the cut-off low centered off the California coast in place 
through most of the period, however the arrival of an upper-level 
trough from the NW will disrupt the continuous SW flow over the area 
and usher in a cooler airmass, offering more of a respite from the 
recent heat than the incoming smoke layer aloft already has. 
Ensemble clustering solutions in much better agreement on depicting 
this upper-level low, with its impacts expected to remain mostly 
north of the forecast area, except for the central WA Cascades which 
may see a light shower Thursday afternoon. The net effect of this 
oncoming system will be to shift the winds aloft more westerly, 
which may help to push the smoke layer away from our area. The 
cooler NW air coming in from behind this system will also help keep 
temps around seasonal averages, with highs Thursday and Friday 
expected to be primarily in the 80s through mid 90s.

Ensembles not doing much to budge the offshore low further inland by 
next week, with some members developing a ridge between the offshore 
low and the departing upper-level trough by the weekend. Consensus 
across guidance seems to follow this solution, as temperatures look 
to warm up over the weekend, inching closer back to the century mark 
in the lower Basin by Sunday. The tilt of this ridge may allow for a 
reintroduction of SW flow over the eastern mountains, with some QPF 
ensemble members suggesting a slight chance of showers for the area 
Friday onward. Signal for precip is pretty weak, however, so leaning 
towards a primarily dry forecast for now. The orientation of the 
potential ridge over the weekend will also impact whether or not we 
see a more extended period of smoke aloft from the wildfires over 
southern Oregon and northern California as well. Evans/74

AVIATION...06z TAFs...VFR conditions expected through the forecast 
period with continued haze from the N. California fire. Mostly bkn-
ovc CIGs ranging from 10-15 kft overnight increasing to 25 kft with 
an elevated smoke layer mixed in. Winds will continue to increase 
through the forecast period with sustained winds around 10-20 kts 
and gusts up to 20-30 kts possible. 90

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  67  95  61  96 /  10   0   0   0 
ALW  69  97  65  98 /  10   0   0   0 
PSC  71 100  64 100 /  10   0   0   0 
YKM  61  96  56  96 /   0   0   0   0 
HRI  71  99  65  99 /  10   0   0   0 
ELN  62  91  59  93 /   0   0   0   0 
RDM  62  93  57  94 /  10  10  10  10 
LGD  63  91  58  93 /  10  10   0   0 
GCD  65  92  59  95 /  20  10  10  10 
DLS  69  93  64  94 /  10   0   0   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT this evening for ORZ640-642.

     Red Flag Warning until 9 PM PDT Tuesday for ORZ641.

WA...     Red Flag Warning until 9 PM PDT Tuesday for WAZ690-691.

&&

$$

SHORT TERM...77
LONG TERM....74
AVIATION...90