Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 170926
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
226 AM PDT Tue Jul 17 2018

.SYNOPSIS...
High temperatures will soar into the mid 90s to around 100
degrees again this afternoon. A Heat Advisory remains in effect
for much of central Washington through this evening. Temperatures
won`t be as hot Wednesday through Friday, but will remain above
average. The arrival of a cold front over the weekend should bring
readings down close to normal.

&&

.DISCUSSION...
Today through Wednesday Night: The trough that brought some high
clouds to the region overnight is moving into western Montana.
Some of this wrap around high level moisture will remain across
the region today, but still sunny or mostly sunny skies are
expected. Another wave will move in with the westerly flow late
this afternoon bringing a slight chance of thunderstorms to the
northern Cascades along the Canadian border through early evening.
The westerly flow on the west side means a growing marine layer.
Today it will be fairly shallow. This will produce a pressure
gradient across the Cascades and bring increasing winds in the
late afternoon and through the evening. Wednesday the marine layer
deepens more creating a stronger gradient for even slightly
stronger winds than today. These winds in combination with very
low daytime relative humidities means fire weather concerns. Will
keep the red flag warning going for today through Wednesday
evening. Today will be the last hot day before we start to see
some relief. A heat advisory remains in effect for central WA
through 8pm. Temps in the mid 90s to low 100s is expected with a
cool down Wednesday of 4 to 6 degrees. /Nisbet

Thursday and Friday: The hot high pressure ridge over the Western
US and southern Plains will be suppressed by an upper low
organizing along the BC coast Thu and Fri. As 500mb heights
decrease over the Pacific Northwest and onshore flow increases,
high temps across eastern Washington and north Idaho will gradual
"cool" into the mid 80s to low 90s. Look for late afternoon and
early evening gap winds around Wenatchee, Chelan, Waterville, and
Vantage leading to heightened wildfire danger. The GFS and ECMWF
are in good agreement that humidity levels will be particularly
low on Friday with most lowland areas experiencing afternoon
relative humidity in the teens.

Saturday through Monday: The BC low is forecast to track into
southern Alberta over the weekend. At this time, it looks like the
low passing to our north will do little to increase our chances
for rain. Unfortunately, breezy north winds will likely develop as
our surface pressure gradient stack up along the Canadian border.
MOS from the GFS and ECMWF forecast breezy north winds down the
Okanogan Valley onto the Waterville Plateau over the weekend and
possibly into Monday. The good news is the north winds should
knock temperatures down into the 80s Sat and Sun...about average.
The not so good news will be the heightened grass and brush fire
threat for areas of central Washington prone to north winds.
/GKoch

&&

.AVIATION...
06Z TAFS: VFR conditions for the area through the next 24 hours.
High cirrus will spread over region through Tuesday afternoon. Much
of this cloud cover will be over southeast WA and into the southern
to central ID Panhandle. Winds will generally be light, but drainage
winds will be a bit breezier from the northwest into KEAT late
Tuesday afternoon and evening with gusts to around 20 kts expected.
/SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        95  62  89  60  88  57 /   0   0   0   0   0   0
Coeur d`Alene  94  57  88  56  86  54 /   0   0   0   0   0   0
Pullman        92  57  85  55  86  53 /   0   0   0   0   0   0
Lewiston      100  65  94  63  94  60 /   0   0   0   0   0   0
Colville       96  57  92  56  92  53 /   0   0   0   0   0   0
Sandpoint      91  54  85  53  86  52 /   0   0   0   0   0   0
Kellogg        91  55  84  54  85  53 /   0   0   0   0   0   0
Moses Lake    101  59  94  58  92  56 /   0   0   0   0   0   0
Wenatchee      98  66  92  63  91  59 /   0   0   0   0   0   0
Omak          101  61  95  59  93  56 /   0  10   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Red Flag Warning from 1 PM this afternoon to 8 PM PDT this
     evening for East Washington South Central Cascade Valleys
     (Zone 676).

     Red Flag Warning from 4 PM this afternoon to 10 PM PDT Wednesday
     for East Washington Central Cascade Valleys (Zone 677)-East
     Washington Northern Columbia Basin (Zone 673).

     Heat Advisory until 8 PM PDT this evening for Moses Lake Area-
     Okanogan Valley-Upper Columbia Basin-Waterville Plateau-
     Wenatchee Area.


&&

$$



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