Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 232113
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
213 PM PDT Sun Jul 23 2017

.SHORT TERM...Tonight through Wednesday...Main weather concern is
thunderstorm development associated moisture moving north out of
CA east of upper level low moving onshore by Tuesday. Models in
pretty good agreement on slow movement of upper low onshore Monday
night and then opening up into a wave and moving across central
and eastern Oregon Tuesday night and Wednesday. Pretty distinct
line where westerly flow shunts moisture to the east. Will have a
slight chance or chance of thunderstorms tonight into Wednesday
mainly south of a line from Madras to Enterprise Oregon. This will
be a critical fire weather event on Monday, so see fire weather
discussion for additional details. Rest of area from northern
Oregon through eastern Washington will remain dry due to the
westerly flow aloft. Though temperatures will be not as hot as
today, they will still average above normal. Winds should not be
much concern after this evening, except of course, locally gusty
near thunderstorms.


.LONG TERM...Wednesday night through Sunday. Hot and dry conditions
will be seen through the extended period. The upper low will
continue to move east Wednesday night with a little lingering
moisture over the extreme east.  Southwest flow will return to the
area for Thursday through the weekend as the western ridge returns
to the area. The GFS model shows some moisture and instability
moving through the ridge over the Blue Mountains at times, but the
ECMWF has dry conditions.  The GFS hasn`t been very consistent with
the moisture features, so have gone with the dry forecast. This will
need to watched as the ridge sets up to see if any moisture will be
available to be transported over the area.  Saturday and Sunday the
ridge shifts further northwest, centered over Nevada and will push
temperatures in the lower elevations near 100. 93

&&

.AVIATION...00Z Tafs. VFR conditions will prevail over the next 24
hours. Mid and higher level moisture will continue to spread into
central Oregon with some isolated showers and thunderstorm over the
Cascades through the evening, but not expected to impact KRDM and
KBDN this evening, then clearing. Isolated showers and
thunderstorms will be possible in this area again Monday afternoon
and evening. Mostly clear skies will continue over the remainder
of the sites. Gusty winds will be seen at the tafs sites through
06z with west to northwest wind 10-15 kts with gusts to 20-25 kts,
then decreasing 06Z. 93

&&

.FIRE WEATHER...Breezy conditions can be expected late this
afternoon and evening across the Columbia Gorge/Basin. With RH`s too
high in the Gorge and winds remaining 15 mph or so in the Basin,
will highlight the risk in the planning forecast and not issue a Red
Flag Warning. This leaves the main concern being thunderstorms
tonight through midweek. For tonight, think limited deep moisture
will cap coverage at isolated across Central Oregon. Moisture
will increase Monday/Monday night, and with sufficient
instability, think scattered thunderstorms will prevail across the
Central Oregon plateau and highlands. Thus, will issue a Red Flag
Warning for abundant lightning for zones 611, most of 642, and
the southern portion of 640 Monday afternoon and evening. Expect
additional thunderstorms Tuesday, but looks like coverage will
remain isolated. For Wednesday, the upper low will open up as a
trough and cross the eastern OR mountains for a slight chance of
thunderstorms. Ridging is progged to rebuild over the area for
late week into next weekend for dry and hot conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  62  91  61  95 /   0   0   0   0
ALW  65  93  65  96 /   0   0   0   0
PSC  63  94  59  97 /   0   0   0   0
YKM  62  93  62  96 /   0   0   0   0
HRI  64  93  61  97 /   0   0   0   0
ELN  57  90  58  94 /   0   0   0   0
RDM  56  89  55  92 /  20  20  20  20
LGD  57  90  54  92 /   0   0  10  10
GCD  62  93  59  93 /  20  30  30  20
DLS  64  94  63  96 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning from 2 PM to 11 PM PDT Monday for ORZ611-640-
     642.

WA...None.
&&

$$

79/93/93



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