Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 042137
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
237 PM PDT SAT JUL 4 2015

.SYNOPSIS....
Hot and dry weather will be featured for the Independence Day
weekend. Saturday night into Sunday winds will shift to the north
and increase as a front sags in from Canada. Aside from isolated
shower chances toward the Idaho Panhandle, conditions looking dry
and warm into the first half of next week. A slight chance of
showers and thunderstorms returns late next week.


&&

.DISCUSSION...
Tonight through Saturday: The Inland NW will be in a west to
northwest flow through the middle of next week. This will be
accompanied by the occasional shortwave passage with breezy to
windy conditions and minor shower chances. Toward later next week
low pressure off the California coast begins to shift inland,
bringing the potential for more scattered showers and
thunderstorms. As a whole the pattern remains dry, with moderating
but still above normal temperatures.

Between tonight and Sunday night the first shortwave crosses the
Inland NW. That feature was dropping across BC this afternoon and
it`ll usher the cold front across the Canadian border this
evening. This will lead to strengthening northerly winds through
the evening into Sunday. Just in time to heighten the concern
around the Fourth of July evening, speeds will be or rise into in
the breezy category. Directions turn north-northwest over much of
the region Saturday night, before they gradually shift north-
northeast into Sunday. We will continue to see some channeling and
higher winds down the Okanogan Valley and out through the Purcell
Trench. Speeds then begin to subside Sunday afternoon and
especially Sunday night.

There is a marginal increase in layer moisture and instability
along the front and just ahead of the mid-level shortwave,
especially toward the ID/MT border. Look for a band of clouds to
drop by Saturday evening into Sunday morning, with slight
shower/thunderstorm chances along the ID/MT border. For Sunday
afternoon shower and thunderstorm chances will continue across
portions of the lower Panhandle, including southeast Shoshone
county and possibly toward the Camas Prairie. However in that
latter region confidence is very low. In general, however, a
reinforcing shot of drier air starts to spread down from Canada
overnight into Sunday just on the heels of the mid-level
shortwave. So most of the region will stay precipitation-free.

Between Monday night and Tuesday night the second substantial
shortwave drops through. This system carries slightly more
moisture and instability and overall has a better threat of
showers and thunderstorms. Some clouds increase Monday night,
with the threat for a few showers nudging toward the northern
Panhandle. The better chances develop across the northern
mountains through northern Panhandle going into Tuesday
afternoon, before waning through the evening and overnight.

From Wednesday to Saturday the pattern begins to evolve a bit,
with low pressure off the CA coast migrates inland through the end
of the week. Some instability wraps around the mountains, while
the deeper Columbia Basin remains relatively stable. Where models
disagree is over whether how much energy coming around that
incoming low drifts north into our region to bring at least an
isolated shower and thunderstorm threat. Through Thursday most
models keep the threat south of the region of just into our
Blues/Camas Prairie. The GFS brings chances into the Cascades by
Thursday, but for now this seems an outlier. By next Friday into
Saturday better chances come to the southeast WA and the lower
Panhandle and move up along the ID/MT border, with a few solutions
wrapping some threat back across the northern WA mountains.
Overall look for an increasing threat going into the end of next
week. /J. Cote`

&&

.AVIATION...
00Z TAFS: A cold front sags in later Saturday evening, with a few
more middle to high clouds. A more notable feature will be
strengthening winds at some TAF sites, especially away from
PUW/LWS. The first increase is expected this evening, followed by
a second surge late Saturday night/Sunday morning. Speeds near 15
to 25kts with gusts toward 30 to 35kts will be possible,
especially toward COE and MWH with that second surge. Winds are
expected to slowly decrease later in the day Sunday, but gusts
toward 20 to 25kts will be possible even after 18-20Z. Expect some
elevated some layers from regional wildfires. Otherwise TAF sites
will be dry and VFR. /J. Cote`

&&


.FIRE WEATHER...
Red Flag Warnings continue for portions of the central and
northeast Washington through early to mid Sunday afternoon. A dry
cold front is projected to drop southward from Canada between
6 to 10 pm tonight, which will increase winds and gusts across
the region. The biggest concern remains gusts of 30 to 40 mph
and a fair amount dry air coming behind the frontal passage,
especially at around 850mb (or 4000 feet). Poor recoveries are
expected in the mountains and potentially the valleys should this
drier air mix in. We should rise above the critical RH thresholds
briefly near 5 AM but drop again. The strength of the sustained
winds is expected to wane after about 20-22Z (1 to 3 PM). General
winds improve into the remainder of the week, but RHs values
remain low through, with continued above normal temperatures.

There will be slight thunderstorm chances around Tuesday in the
northern mountains and a broader, but still slight, shower and
thunderstorm threat arrives toward the end of next week as low
pressure off the CA coast starts to move inland. /J. Cote`


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        67  89  61  91  67  93 /  10  10   0   0   0  10
Coeur d`Alene  62  85  57  89  61  90 /  10  10  10   0   0  20
Pullman        58  89  53  90  56  92 /   0  10  10   0   0  10
Lewiston       71  98  65  98  68  99 /   0  10  10   0   0  10
Colville       61  92  57  94  62  93 /  10  10   0   0  10  10
Sandpoint      55  83  49  88  54  86 /  10  10  10   0  10  20
Kellogg        61  83  52  88  57  87 /  10  10  10   0   0  20
Moses Lake     71  97  66  98  67 102 /   0   0   0   0   0   0
Wenatchee      74  98  72  99  72 100 /   0   0   0   0   0   0
Omak           66  96  63  97  65  97 /   0   0   0   0  10  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Red Flag Warning until 1 PM PDT Sunday for East Washington
     Northeast (Zone 686).

     Red Flag Warning until 3 PM PDT Sunday for East Washington
     Northern Columbia Basin (Zone 673)-East Washington Okanogan
     Highlands (Zone 687)-East Washington Okanogan/Methow
     Valleys (Zone 684).

&&

$$


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