Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 301120
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
420 AM PDT Sat Jul 30 2016

.SYNOPSIS...
The passage of a dry cold front today will produce dry and breezy
conditions. Winds will peak this afternoon and early this evening
raising concerns for rapidly spreading wildfires. Sunday will be
cooler with afternoon highs in the 80s. Another potent cold front
is expected on Tuesday, and will likely produce more windy weather
as well as the chance for thunderstorms along the Canadian border.
A dry weather pattern with less wind is expected Wednesday
through Friday.


&&

.DISCUSSION...

Today through Sunday night...The transition from a flat ridge of
high pressure to a general trof of low pressure due to numerous
disturbance passages moving through it occurs through this time
interval. Models continue to depict most of the convection
associated with the disturbance passages to remain within close
proximity to the Southern British Columbia Border with not much
extent south of it except perhaps over part of the Northern
Panhandle Mountains of Idaho, otherwise the disturbances will mostly
generate breezy winds. These winds combined with dry conditions
continue to be highlighted with red flag warnings in parts of the
forecast area this afternoon and evening. The cooling trend brought
about this scenario continues through the weekend as well with
forecast temperatures of upper 80s and 90s falling 8 degrees or so
down into the 80s for Sunday. /Pelatti

Monday: Our temperatures are expected to climb to near average
(mid to upper 80s) on Monday as the Inland Northwest experiences
a relatively tranquil day. Chances for showers and thunderstorms
will increase over the northern Cascades Monday evening and into
the overnight hours as a compact low pressure system moves into
western Washington. The resident air mass over the Pacific
Northwest will be very dry in advance of this low. Convection will
likely be tight to the center of the low Monday night into
Tuesday since cooling aloft will be necessary to generate the
instability given the limited moisture availability.

Tuesday: Tuesday will be another day to watch for heightened
wildfire concerns. Gusty winds will be possible region-wide and
lightning along the Canadian border may an issue. A blend of the
ECMWF and GFS was used for the Tuesday`s vigorous cold front.
Strong cold advection combined with a tight westerly surface
pressure gradient will have the potential to produce gusty winds
from the early morning through the evening. At this time, it looks
like sustained winds of 15 to 20 mph with gusts to 30 mph will be
common with localized gusts of 35 mph in the lee of the Cascades
late in the afternoon. Tuesday`s temperature should be about 10
degrees below average with humidity levels on the rise. However,
an all-day wind event will have the potential to push fires,
especially those over the grass/sage country of central/eastern
Washington.

The potential for scattered showers and thunderstorms will be a
concern under the core of the upper low on Tuesday. At this time,
the track of the upper low gives the best shot of lightning along
and north of Highway 2 in Washington and over Bonner and Boundary
counties in north Idaho.

Wednesday: The surface pressure gradient weakens markedly by
Wednesday. Look for decreasing winds, seasonably warm
temperatures, and dry weather on Wednesday. /GKoch

Wednesday night through Saturday... Models start off in pretty
good agreement with a closed low dropping out of the Gulf of
Alaska and sliding down the BC coast. They diverge however by
Thursday night with the GFS and GFS ensemble pushing the low
eastward into BC while the ECMWF and Canadian continue to dive it
southward. In either solution, expect a mainly dry forecast.
While I can`t completely rule out a stray mountain shower,
forecast soundings appear too dry to include in the forecast.
Perhaps the bigger impact as to which model solution verifies is
the temperature and wind forecast for next weekend. Until that
point, I expect temperatures near their seasonal norms in the mid
80s to low 90s for the Thursday/Friday time period. /Kalin

&&

.AVIATION...
12Z TAFS: VFR conditions expected at all TAF sites through 12Z
Sunday. A weak cold front will push across the region tonight.
Precipitation along the front will limited to along the Canadian
border in eastern WA and in the Northern Panhandle. Winds will
become breezy on Saturday. Expect sustained winds of 12-18 kts
with gusts up to 25 kts at most TAF sites. A tighter pressure
gradient across the Cascade Mtns will result in windier conditions
at KEAT with gusts to between 30-35 kts possible, especially for
the afternoon into early Saturday evening.


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        90  58  82  58  86  57 /   0   0   0   0   0  10
Coeur d`Alene  89  55  81  54  86  54 /   0   0   0   0   0  10
Pullman        88  49  81  50  85  52 /   0   0   0   0   0   0
Lewiston       97  60  90  60  94  60 /   0   0   0   0   0   0
Colville       91  54  84  51  88  52 /   0   0   0   0   0  10
Sandpoint      86  52  79  49  82  50 /   0   0   0   0   0  10
Kellogg        87  53  78  51  84  51 /   0   0   0   0   0  10
Moses Lake     95  58  88  57  90  58 /   0   0   0   0   0  10
Wenatchee      92  63  86  61  88  61 /   0   0   0   0   0  10
Omak           93  59  88  59  89  59 /   0   0   0   0   0  20

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
     evening for East Washington Central Cascade Valleys (Zone
     677)-East Washington Northern Columbia Basin (Zone 673)-
     East Washington Palouse and Spokane Area (Zone 674).

&&

$$


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