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Area forecast discussion...updated 
National Weather Service Pendleton or
151 PM PDT Thursday Jul 31 2014

Updated aviation discussion

Short upper ridge will continue over the western
U.S. Through Friday. The ridge axis will largely run through Nevada
into Idaho, east of Oregon and Washington during this period. The
upper level flow over the pacnw will become more south to
southwesterly today. As such, lingering subtropical moisture will
gradually work into our Washington zones. Weak disturbances within
the upper flow will continue to cause the development of showers and
thunderstorms through the next 24 hours. A wave moving through the
area this morning is causing a few showers and the odd lightning
strike over portions of our Oregon zones. Have updated morning
forecasts to cover the area of showers associated with this wave. A
second wave will move through the region late today and tonight.
This will keep varying amounts of showers and storms going over our
Oregon zones through tonight. Will have to look at the potential of
at least a few showers drifting into south-central Washington
overnight for the afternoon issuance. High temperatures will remain very
warm, but should be 2-3 degrees cooler than yesterday due to
increased cloud cover. Updates other than those already mentioned
included adjustments to sky cover and tweaks to high temperatures and
winds. 90


Aviation...18z tafs...VFR conditions will prevail through the next
24 hours. Expect mostly broken-overcast high clouds from cumulonimbus thunderstorm
anvil debris in central Oregon and the ochoco-John Day Highlands
beginning later this afternoon and scattered-broken middle level clouds over
NE Oregon and southeast Washington associated with scattered showers and
isolated thunderstorms over the Blue Mountains, the Elkhorn
Mountains and in Wallowa County through this afternoon into this
evening. Thunderstorms will develop this afternoon starting around
22z in central and east central Oregon. Kbdn and krdm have thunderstorms in the vicinity
beginning around 22z and thunderstorms in the vicinity will be possible for several hours
with thunderstorms likely to be nearby. Sustained winds will be
light upslope less than 10 kts, except at kdls where winds this
afternoon will be 12-15 kts with gusts to 20 kts. Polan


Long term...previous discussion...eastern Oregon and Washington
will remain on the western side of an upper level ridge Saturday
night and Sunday. A wave will move through the area and trigger
thunderstorms Saturday night and Sunday in eastern Oregon and along
the Washington Cascades. Monday and Tuesday dry westerly flow will
develop and push the monsoonal moisture south and east. However
enough instability and moisture may linger over the northeast Oregon
mountains to trigger thunderstorms again during the


Fire weather...warm and dry conditions continue under a ridge of high
pressure with overnight humidity recovery poor to moderate.
Thunderstorm chances will increase and spread north and east each
day through the weekend. Most storms should stay south of the
Washington border until Friday and Saturday. Storms that develop
will be a mixture of wet and dry with precipitation ranging from a
few hundredths of an inch to around a quarter of an inch. Red flag
warnings are in effect for abundant lightning across central Oregon
through Saturday. Scattered thunderstorms will be possible across
the mountains of northeast Oregon and far southeast Washington
starting this afternoon. The red flag warning for the northeast
mountains starts this afternoon and GOES through Saturday. Dmh


Preliminary point temps/pops...
PDT 100 67 97 66 / 20 20 20 20
alw 101 72 99 71 / 10 10 20 20
psc 103 67 100 67 / 10 10 20 20
ykm 99 66 98 67 / 0 10 20 20
hri 101 66 100 66 / 10 10 20 20
eln 100 61 95 61 / 0 10 20 20
rdm 95 56 92 55 / 30 30 30 30
lgd 95 59 92 60 / 30 30 30 30
gcd 97 62 93 60 / 30 30 30 30
dls 97 67 97 67 / 10 10 20 20


PDT watches/warnings/advisories... flag warning until 11 PM PDT Saturday orz503-505-506-509>511.

Red flag warning from 1 PM this afternoon to 11 PM PDT Saturday

Red flag warning until 11 PM PDT Saturday orz049. flag warning from 1 PM this afternoon to 11 PM PDT Saturday


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