Wildfire in Washington, July 18 to 22, 2019

Area Forecast Discussion
National Weather Service Pendleton OR
139 PM PDT Thu Jul 18 2019

.SHORT TERM...Tonight through Sunday. Upper low centered over
southern BC with westerly flow into Washington and Oregon. Visible
imagery shows cumulus is decreasing as airmass mixes out.
Expecting clear to partly cloudy skies through the evening and
overnight. Most of the cloudiness will be along the Cascades with
onshore flow. Westerly winds have increased today and this will
continue through evening then diminish. The upper low is moving
east out of the region on Friday. Westerly flow is decreasing and
winds will be lighter. Some morning clouds over the mountains
otherwise a sunny day. Heights are rising Saturday and Sunday as
the upper ridge builds northward. The thermal trough will also be
moving into the area and this will bring a warming trend over the
weekend. Highs Saturday in the 80s with upper 80s to mid 90s Sunday.
Skies will be mainly clear. 94

.FIRE WEATHER...Red flag warning remains in effect into the
evening for gusty winds and low RH across the Columbia basin.
Westerly winds 15-30 mph will diminish after sunset. 94

.LONG TERM...Sunday night through Thursday...Upper ridge will become
established over the central Rockies and build westward into the
Pacific NW late in the weekend into early next week bringing
increasing heat. Meanwhile an upper trough just offshore will nudge
into the region by Tuesday night and Wednesday bringing cooler
weather and perhaps a slight chance for Thunderstorms. For Monday it
should remain mostly dry and hot with high temperatures well into
the 90s in the lower elevations. There is a minor concern for high
based thunderstorms over the eastern Mountains late Monday given
some instability. However soundings seem a bit dry to get much going
and large scale forcing for ascent appears minimal. For these
reasons have kept POPS in the 10-14% range for now on Monday with
some time yet for further evaluation. On Tuesday the threat for
isolated storms over the eastern mountains appears just a bit higher
as the trough moves inland. If the operational GFS is correct a
strong shortwave trough moves through Tuesday night which could lead
to evening/nighttime thunderstorms. By Wednesday the limited
moisture gets pushed to the east and it should be dry with more
seasonable temperatures through Thursday. 78

.AVIATION...00Z TAFS...VFR Conditions with mostly clear skies will
prevail through the forecast period. West to northwest winds of
15G30 kt will diminish after 06Z. Winds Friday afternoon will be
mostly 6-12 kt except 10-20 kt at KDLS. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  48  79  48  86 /   0   0   0   0
ALW  51  81  51  87 /   0   0   0   0
PSC  51  83  50  88 /   0   0   0   0
YKM  46  81  49  87 /   0   0   0   0
HRI  50  83  50  88 /   0   0   0   0
ELN  47  75  47  83 /   0   0   0   0
RDM  40  78  41  84 /   0   0   0   0
LGD  44  75  43  82 /   0   0   0   0
GCD  43  77  44  85 /   0   0   0   0
DLS  51  81  52  88 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 9 PM PDT this evening for ORZ641.

WA...Red Flag Warning until 9 PM PDT this evening for WAZ641-675.

&&

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