Freeze Warning 7, NWS Pendleton, OR

Area Forecast Discussion
National Weather Service Pendleton OR
217 PM PDT SUN SEP 11 2016

.SHORT TERM...Tonight through Wednesday...A weak cold front is
moving into MT this afternoon. Breezy winds have developed in parts
of the eastern Columbia Basin and Deschutes Plateau this afternoon
behind the front. Scattered cumulus clouds have developed north of a
Hanford to La Grande line. These clouds will diminish after the
atmosphere stabilizes near sunset.

Dry northerly upper level flow will slowly shift northeast Monday as
the upper level trough stretches out and a cutoff low develops over
northern CA. Pressure gradients will tighten again Monday
afternoon...resulting in breezy to windy conditions for the Columbia
Basin and surrounding valleys. There may be patchy blowing dust
Monday afternoon across the Basin. Seasonably cool high temperatures
will continue Monday.

Pressure gradients will decrease Monday night. Clear skies and light
winds will allow good radiational cooling to occur. Nighttime
temperatures will be chilly...with lows around 40 in the lowest
elevations. Central Oregon will be near 30 Monday Night. A Freeze
Watch has been issued...with several hours of freezing temperatures
possible.

Dry northeast flow will continue Tuesday and early Wednesday. Most
of the moisture rotating around the cutoff low will remain south of
the CWA though a few clouds are possible from Grant to Wallowa
Counties. Coonfield

.LONG TERM...Wednesday night through Sunday...Models are in good
agreement in building an upper level ridge over the area through
Saturday. There are discrepancies in the amplitude and position of
the ridge...but overall the weather will remain dry with a warming
trend.  By Saturday...the ridge gets flattened/pushed east in
response to the next upstream trough.  As a result...the upper level
flow becomes more zonal Saturday night into Sunday.  This flow may
produce some isolated showers over the Washington Cascades Sunday
afternoon. Daytime highs will remain above normal through the
period.  Earle

&&

.AVIATION...00Z TAFS...VFR conditions will continue through the
period. A few mid/high level clouds will drift through the area.
Winds will generally be W-N 10-20 kts with higher gusts through the
early evening...decreasing overnight. Winds will increase again
Monday afternoon to 10-20 kts and gusty.  Earle

&&

.FIRE WEATHER...A deepening trough with a low developing in Northern
California will cause strong northerly winds on Monday. Relative
humidity will also be less than 20 percent across portions of the
Columbia Basin, and Red Flag Warnings are being issued for Monday
afternoon and evening. The fine fuels, which include grass and
brush, are very dry, and any new fires will spread rapidly.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  70  41  72 /   0   0   0   0
ALW  46  73  45  75 /   0   0   0   0
PSC  49  75  42  76 /   0   0   0   0
YKM  44  76  39  78 /   0   0   0   0
HRI  47  75  40  76 /   0   0   0   0
ELN  42  73  39  77 /   0   0   0   0
RDM  34  66  29  71 /   0   0   0   0
LGD  41  67  37  71 /   0   0   0  10
GCD  38  66  31  72 /   0   0   0   0
DLS  47  78  44  81 /   0   0   0   0

&&

.PDT Watches/Warnings/Advisories...
OR...Red Flag Warning from 11 AM to 9 PM PDT Monday for ORZ641.

     Freeze Watch from late Monday night through Tuesday morning for
     ORZ511.

WA...Red Flag Warning from 11 AM to 9 PM PDT Monday for WAZ639-641-
     675.

&&

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