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fxus66 kpdt 162320 

Area forecast discussion
National Weather Service Pendleton or
420 PM PDT sun Jun 16 2019

Updated aviation discussion

Short term...tonight through Wednesday...main weather concern
during the short term period with be the breezy to windy
conditions and how winds will impact fire behavior for any new
and existing fires. There is also a potential for winds to reach
advisory criteria in the Kittitas Valley and the eastern Columbia
River gorge Tuesday and Wednesday. A weak marine surge is already
causing 20-25 mph winds in the eastern Columbia River gorge. The
marine layer west of the Cascades is quite shallow-- approx. 2800
feet on the 12z Quillayute sounding. However, the marine layer
will deepen over the next 48 hours aiding in a stronger marine
push by Tuesday. The high pressure ridge has flatten and increased
a westerly flow aloft this afternoon, along with the increasing
onshore flow. From Monday through Wednesday, high pressure will
strengthen between 130-140w and the Pacific northwest will be on the east
side of the ridge and under a west-northwest flow aloft. Monday's
winds will be about the same or a little stronger than today. On
Tuesday, an upper level shortwave and surface cold front will
bring dry but windy conditions to many areas. At this time, it
does not appear to be critical fire weather conditions due to the
cooler temperatures and higher humidity. But, there are areas that
need to be closely monitored, particularly the Hanford district
and Yakima training center. A strong westerly flow aloft and tight
pressure gradients on Wednesday will mean another day of gusty
winds on Wednesday. The air mass will be dry above the boundary
layer despite the increasing surface humidity due to the strong
marine push. Fire weather highlights may be in order for
Wednesday, and this will be addressed in future discussions.

Towering cumulus have developed in The Blues and wallowas this
afternoon but too shallow for any convection today. However, on
Monday, a shortwave traveling southeast will encounter some
instability in this area and may bring a few showers or
thunderstorms in Wallowa County. This was included in the
forecast. The remainder of the short term period will be dry.

Long term...Tuesday night through next Sunday...a dry and stable
northwest flow will dominate at least the first part of the extended
period through at least Friday. There will be weak disturbances in
the flow which may bring clouds and breezy to windy conditions at
times. There could be a few showers from time to time in the
mountains. It will be too stable for least at the
beginning of the extended period. The combination of wind and low
humidity with very warm conditions may pose a fire weather threat at
times and may possibly need highlights for fire weather hazards. By
Saturday the long range models will differ more significantly from
each other with one showing a ridge and another showing a closed
upper low at the same time. During these times (the latter part of
the extended forecast period) did not make too many changes due to
the model uncertainty. It will remain warm and mostly dry with
breezy to windy conditions at times. The chances for showers and
possibly afternoon thunderstorms will increase by Sunday. It will be
warm through Wednesday and then there will be a cool down into the
70s to around 80 in the lower elevations for Thursday and Friday.
Then it will warm up again back into the 80s for all lower
elevations by Saturday and Sunday. 88


Aviation...00z tafs...VFR conditions will prevail during the next
24 hours. Winds will be under 10 kts, except they will be
locally breezy through this evening along the east slopes of the
Cascades and then decrease overnight. Winds will increase again
Monday afternoon in these same areas but remain less than 10 kts
rest of the forecast area.


Preliminary point temps/pops...
PDT 58 85 58 83 / 0 0 0 0
alw 61 88 60 87 / 0 0 0 0
psc 62 92 61 90 / 0 0 0 0
ykm 60 89 58 85 / 0 0 0 0
hri 61 90 60 88 / 0 0 0 0
eln 57 80 58 75 / 0 0 0 0
rdm 48 84 48 82 / 0 0 0 0
lgd 54 82 53 81 / 0 0 0 0
gcd 52 82 52 81 / 0 0 0 0
dls 59 82 60 79 / 0 0 0 0


PDT watches/warnings/advisories...

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