Area forecast discussion...update
National Weather Service Pendleton or
330 PM PDT Wednesday Jun 19 2013
Updated for aviation discussion
Short term...today through Saturday. Stationary low pressure over
the pacnw will continue to pump moisture into our area tonight and
especially over the eastern County Warning Area. There could be some clearing in the
sky cover over central Oregon to make the atmosphere unstable enough
to produce an isolated thunderstorms and rain. Otherwise windy conditions will continue
over the Kittitas Valley where a Wind Advisory is in effect this
evening.
The low pressure slowly tracks across our area tomorrow before
moving into western Montana Thursday afternoon. Still the clouds and
showers will persist across the area with isolated thunderstorms and rain possible over
the blue/Wallowa Mountains
The low remains nearly stationary and the unsettled weather
continues into Friday and temperatures will remain below normal. By
Saturday a ridge of high pressure builds into the region and most of
our area should be drier while afternoon temperatures rebound to
around 80 degrees in portions of the basin.
Long term...Saturday night through Wednesday...a brief break in
systems as weak high pressure will be over the area Saturday night
into Sunday. By Sunday evening precipitation chances will once
again increase as the next upper level disturbance approaches the
area. Models are hinting at a negative tilt with this system...and
that there is a slight chance for thunderstorms along the mountains
of northeast Oregon on Sunday evening. As the low slowly moves down
the Gulf of Alaska and closer to the coast...precipitation chances
will increase on Monday and Tuesday. There will continue to be a
slight chance of thunderstorms along the mountains of northeast
Oregon...and southeast Washington Monday and Tuesday.
Tuesday Onward...right now models hold the low off the
Seattle...Vancouver Island coast. This will continue to bring waves
of precipitation to the area. The main differences in the models
are...the European model (ecmwf) model begins to build a Four Corners high towards
the middle week...which would bring temperatures up and precipitation
chances down. GFS model has the high pressure more over the center
of the US...and the ridge is less amplified. This would suggest a
milder and possibly moister extended...with both showers and
thunderstorms possible. Confidence in Tuesday Onward forecast is
currently low for both the precipitation and temperature.
Weber
&&
Aviation...previous discussion...18z tafs...an upper level low will
remain over the region for the next 24 hours providing broken middle
level clouds with on and off showers. For the most part taf sites
can expect VFR conditions but...MVFR conditions will not be ruled
out and will likely be on and off at kpdt...kalw...krdm...and kbdn.
Isolated thunderstorms will be possible over central Oregon and the
eastern Oregon mountains until 05z. West winds 10 to 20 kts gusting
to 30 kts...except 15 to 25 kts with gusts to 35 kts at kdls and
kpdt. Winds will remain at 10 to 20 kts with a few gusts to 25 kts
after 06z with the exception of kykm...krdm...and kbdn which will
drop below 10 kts. Winds will pickup again after 15z tomorrow and
be gusting in the 20 to 30 knots range. Showers vcsh will also be
possible after 18z tomorrow for most taf sites. Weber
&&
Preliminary point temps/pops...
PDT 47 66 46 67 / 40 40 30 30
alw 51 66 50 68 / 50 40 30 40
psc 52 69 51 71 / 40 40 30 30
ykm 50 67 48 69 / 40 40 30 30
hri 51 69 50 71 / 40 40 30 30
eln 52 64 49 68 / 40 40 30 40
rdm 35 65 36 67 / 30 20 20 20
lgd 44 61 43 61 / 70 40 30 30
gcd 39 61 38 61 / 50 30 20 20
dls 52 69 52 71 / 40 30 30 30
&&
PDT watches/warnings/advisories...
or...none.
Washington...Wind Advisory until 8 PM PDT this evening waz026.
&&
Threat index
Thursday : green
Friday : green
Saturday : green
Green: none or limited need for watches, warnings, or advisories.
Yellow: a few watches, warnings, or advisories possible or in effect.
Red: numerous watches, warnings, or advisories possible or in effect.
For additional weather information, check our web site at...
www.Weather.Gov/Pendleton
$$
97/89/89
