Scientific Forecaster Discussion
fxus66 kpdt 200530 aaa
Area forecast discussion
National Weather Service Pendleton or
1030 PM PDT Wed Jun 19 2019
Updated aviation discussion
Short term...a 130+ knot northwest jet aimed directly over the
Pacific northwest has aided in strong winds aloft and down to the
surface. For those who Love to look at satellite photos, take a
look at the impressive wave clouds and thick band of cirrus from
Bend to Sunriver, especially on water vapor. A strong marine push
caused winds to reach 30-40 mph with higher gusts along the
eastern valleys of the Washington Cascades, the eastern Columbia
River gorge, and north central Oregon where wind advisories were
in effect. Even a few locations in the lower Columbia Basin had
gusts 40-45 mph this afternoon. Despite the cooling temperatures,
humidity was low and down into the teens over central Oregon.
Latest observations show winds gradually decreasing and humidity
climbing. I will let the Wind Advisory and red flag warning
expire at 9 PM. No major changes were made to the forecast except
to tone down the winds from 03z-06z. It will be a chilly night for
the mountains and wind-protected valleys with temperatures in the
A fairly strong shortwave will swing across the region overnight
and Thursday morning. A few showers and thunderstorms are possible
from the Blue Mountains east to the Idaho border. The SBCAPE
should only be around 250-350 j/kg and bulk shear of 20-30 knots--
not exciting but could be enough for a heavy downpour or small
hail. Breezy winds will continue on Thursday, but it will be about
5-7 degrees cooler than today and the relative humidity will be
in the 20s and 30s with no red flag warning threats. Showers will
end Thursday night, and it will be chilly again with lows in the
30s mountains and 40s elsewhere. A few typically cold spots like
Seneca, Sunriver, and La Pine will be near freezing.
The large upper level trough will travel east on Friday, and
eastern Washington/or will be under a dry northerly flow aloft. High
pressure will return for a dry and warm Saturday with high
temperatures in the 70s to mid 80s. Wister
Aviation...06z tafs...main aviation concern for the next 24 hours
will be the winds that may decrease briefly tonight but increase
again tomorrow with west-northwest winds 10-20 knots and gusts 25-30 knots.
For all sites except rdm and bdn, low level clouds will thicken
tonight to broken-overcast around 5k feet associated with an approaching
shortwave trough. Alw and PDT may observe a few hours of light
showers around sunrise on Thursday. Low level clouds will decrease
behind the shortwave trough Thursday evening. Rdm and bdn will have
scattered-broken high level clouds tonight and Thursday. Wister
Previous discussion... /issued 217 PM PDT Wed Jun 19 2019/
Long term...Saturday night through Wednesday...models are in good
agreement for the long term. Expect weak transient ridging to move
east Saturday night and give way to more westerly flow by Sunday,
bringing a chance of showers for the mountains. Southwesterly flow
aloft sets up by next week with the approach of a closed upper-level
low that will drift south off the coast of British Columbia and set up shop near
the pacnw coast. There will be a chance of showers or thunderstorms,
especially over the mountains, as instability and moisture increases
through the week. Best potential looks to be Tuesday and Wednesday.
Expect temps to be a bit below average for the long term with highs
in the 70s to lower 80s and lows in the 40s to mid 50s. Winds will
likely be breezy at times with a persistent onshore flow and thermal
troughing creating a stronger surface pressure gradient over the
area, strongest on Sunday.
Preliminary point temps/pops...
PDT 46 68 45 72 / 10 20 10 10
alw 51 72 51 75 / 10 40 20 10
psc 53 74 52 78 / 10 10 10 10
ykm 47 72 47 77 / 0 0 0 0
hri 51 73 49 77 / 0 10 10 0
eln 48 66 48 72 / 10 0 0 0
rdm 39 63 37 69 / 0 10 0 0
lgd 44 61 44 65 / 10 40 10 10
gcd 42 62 41 65 / 0 20 10 10
dls 53 69 52 75 / 0 0 0 0
or...Wind Advisory until 9 PM PDT this evening for orz041-508-510.
Red flag warning until 9 PM PDT this evening for orz640-641.
Washington...Wind Advisory until 9 PM PDT this evening for waz024-026.
Red flag warning until 9 PM PDT this evening for waz641-675.