Scientific Forecaster Discussion
Area forecast discussion...update
National Weather Service Pendleton or
437 am PDT Wednesday Jul 23 2014
Updated for aviation discussion
Short term...today through Friday night...lightning strikes have
decreased over the past 3 hours. Infrared satellite indicates that the
colder cloud tops have moved north of the County Warning Area. However models
indicate that another wave will rotate around an offshore upper
level low into eastern Oregon and Washington this afternoon. This
will keep moist unstable over the area. Expect thunderstorms to
redevelop this morning...particularly over central Oregon and
Washington...then spread east in the afternoon. The low will move
into northwestern Washington this evening...with diminishing
precipitation through the night. Winds will become breezy to windy
this afternoon as higher winds aloft mix to the surface. A dry
westerly flow aloft Thursday will bring mostly sunny skies...cooler
temperatures and breezy conditions. Westerly flow continues into
Friday with another sunny day. Temperatures will be warmer with less
Long term...Saturday through Tuesday night...west flow will shift
to the southwest Saturday as a Four Corners high strengthens. Flow
will quickly shift to be southerly...and monsoonal moisture from the
south will make its way to the forecast area. Models don't put out
to much quantitative precipitation forecast with this moisture...so have only gone with a slight
chance of thunderstorms. Right now the slight chance thunder is
over central Oregon on Monday and will spread to northeast Oregon as
well Tuesday Onward. Temperatures will be fairly hot with highs in
the middle 90s to lower 100s starting Sunday and continuing through the
Aviation...12z tafs...expect another day of convective weather for
all taf sites. With convection as early as 18z for the western taf
sites. A low pressure system will move further inland today.
Forcing along with shear and moderate instability will aid in the
potential for strong thunderstorms between 18z-03z. Taf sites will
be breezy with winds 10-15kts gusting 20-25kts. Conditions should
begin to improve after 06z as clouds become more scattered...and the
flow shifts more westerly...as the low moves overhead. Weber
..fire weather...(previous discussion)...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 82 53 79 51 / 40 30 10 0
alw 85 57 78 57 / 40 30 10 0
psc 86 59 82 54 / 30 30 10 0
ykm 78 53 78 54 / 50 30 10 10
hri 84 56 80 53 / 30 20 10 0
eln 75 51 74 52 / 60 30 10 10
rdm 74 38 74 39 / 40 20 0 10
lgd 83 50 72 45 / 40 30 10 0
gcd 82 49 75 48 / 30 20 0 0
dls 74 57 77 56 / 50 30 10 10
or...red flag warning until 11 PM PDT this evening
Red flag warning until 5 PM PDT this afternoon orz509-511.
Washington...red flag warning until 11 PM PDT this evening
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