Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pendleton or
230 PM PDT Tuesday Jul 22 2014
Short term...tonight through Friday. Thunderstorms starting to
develop across central and northeast Oregon this afternoon. Airmass
becoming more unstable now as middle and high level clouds clear. Also
lift will be increasing through the afternoon and evening in
response to approaching California short wave and jet streak. Based
on this expect coverage of showers and storms to increase through
the afternoon and continue into the evening as they move northward.
Jet dynamics will likely result in some stronger storms with hail
and wind. Precipitation should diminish for a while later tonight
before increasing again Wednesday as a large upper low moves into
the Pacific northwest. Expect additional showers and thunderstorms
to move through the area. Models have been consistent showing some
heavier rain possible over the Washington Cascades and east slopes.
As the low moves inland winds will be increasing becoming breezy by
afternoon. Based on the strength of the low level cold advection
many areas may see there highs early in the day with temperatures
becoming steady in the afternoon. Precipitation will diminish
Wednesday night as the low moves off to the east. A dry westerly
flow aloft Thursday with mostly sunny skies, cooler temperatures and
breezy conditions. Westerly flow continues into Friday with another
sunny day. Temperatures will be warmer with less wind. 94
Long term...Friday night through Tuesday. High pressure over the SW
United States will ridge north and influence the regions weather
with dry conditions into the weekend along with warmer temperatures.
Some moisture moves up into the Oregon Cascades Monday afternoon
that could produce isolated thunderstorms and rain over this area into the evening.
Otherwise the dry conditions will persist into next week.
Aviation...local MVFR conditions will persist across all taf sites
and especially over central Oregon until 04z. Showers and
thunderstorms in and near taf sites will create areas of MVFR and
local IFR conditions. Otherwise conditions will improve to mostly VFR
after 10z for all taf sites only to return to local MVFR conditions in
and near kykm after 15z.
Fire weather...a low pressure system moving into the region will cause
widespread showers and thunderstorms. Although some storms may
produce wetting rain...abundant lightning can be expected which
could start new fires in very dry fuels. Storms have begun
developing over central Oregon and the northeast mountains and will
move north into the lower Columbia Basin. Scattered thunderstorms
could potentially last through the night in some places. As the low
moves inland Wednesday...occasional scattered thunderstorms will
again be possible through the evening. Red flag warnings therefore
remain in effect. Cobb
Preliminary point temps/pops...
PDT 62 81 53 78 / 40 40 20 10
alw 65 84 56 79 / 50 40 20 10
psc 64 84 56 82 / 30 30 20 10
ykm 62 77 53 77 / 30 50 20 10
hri 64 83 55 80 / 30 30 20 10
eln 59 74 50 73 / 30 60 30 10
rdm 55 74 42 74 / 50 30 20 0
lgd 57 82 50 72 / 60 40 30 10
gcd 57 83 45 75 / 60 30 20 10
dls 64 73 56 78 / 30 40 30 10
or...red flag warning until 11 PM PDT Wednesday
Red flag warning until 5 PM PDT Wednesday orz509-511.
Washington...red flag warning until 11 PM PDT Wednesday
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