Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 292147
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
247 PM PDT Sat Apr 29 2017

.SYNOPSIS...
A moist front will track across the Inland Northwest tonight and
early Sunday bringing a good chance of precipitation especially
over the eastern third of Washington and the Idaho Panhandle. The
front will likely pass most of the region by afternoon with breezy
conditions expected for most locations. Unsettled weather
continues into Tuesday before a ridge builds into the western US.
The middle of next week will be warm with afternoon temperatures
in the mid 60s to mid 70s before returning to a cooler and
unsettled pattern by the end of the week.

&&

.DISCUSSION...
Tonight through early Sunday...Main forecast impact this period
will revolve around occluded front currently pushing into the
Cascades. Thus far most of the precipitation associated with the
front is being intercepted by the Cascade Crest as westerly flow
through the mid-atmosphere is leading toward orographic ascent in
this region. The 18z models are in decent agreement with the
positioning of the front and its resultant precipitation shield.
This feature is expected to pass through the Columbia Basin and
extreme NE Washington this evening and then into SE Washington and
the southern half of the ID Panhandle overnight. We expect to see
widespread precipitation associated with the front as it moves
into the eastern third of Washington and the ID Panhandle,
although it won`t be terribly heavy. We expect the heaviest
precipitation amounts to occur over the Idaho Panhandle with
amounts ranging from 0.25-0.50 inches with locally heavier amounts
over west facing slopes. Over the Columbia Basin, Okanogan Valley,
and Wenatchee area precipitation amounts will generally be a trace
or less.

Sunday afternoon and evening...after the front moves through, the
main focus will revolve around wind potential. Moderate west to
northwest winds at 850 mbs of 20-30 mph will likely mix down to
the ground with the strongest speeds expected to occur over the
Columbia Basin, Palouse, Waterville Plateau, Wenatchee area, and
Spokane West Plains. Slightly stronger speeds can be expected for
locations with NW-SE alignment. Residual showers will also
continue through much of the day over the Panhandle although the
post-frontal instability is far from impressive and likely far too
shallow to generate thunderstorms. The winds, as well as the
threat of precipitation is expected to taper off rapidly
overnight. fx

Monday through Wednesday Night: A weather disturbance will move
into eastern WA and north ID Monday with another one for Tuesday.
A chance of showers will remain in the forecast...mainly across
the mountains but cannot rule out a shower across the lower
elevations of extreme eastern WA and north ID especially in the
afternoon through early evening. Tuesday night through Wednesday
night a ridge will start to build into the western US. The
forecast drys out with the exception of right along the Cascade
crest. Temperatures Monday start about 5-8 degrees below average
and by Wednesday we will see temperatures 4-8 degrees above
average for this time of the year, mid 60s to mid 70s. /Nisbet

Thursday through Saturday...By Thursday, the Inland Northwest is
on the back side of the ridge axis but will also be the day we
feel the full effects of its warmth. With 850 mb temps between
15-17 C, widespread 70s are expected. The ridge begins to break
down Thursday night and Friday resulting in some shower chances
and cooling temperatures. Depending on the timing and evolution,
the breakdown of this ridge could feature breezy to gusty
conditions. /Kalin

&&

.AVIATION...
18Z TAFS: A weak front will continue to track into the PacNW
through the afternoon and tonight. The main impact through the day
at the forecast sites will be an increasing and thickening cloud
trend, but all sites will see cigs remaining at or above 9k feet.
The front will likely pass MWH and EAT with little impact other
than passing mid-level overcast cigs during the evening but for
the other sites, we expect to see a chance of rain late tonight
into early tomorrow morning. We suspect cigs will remain above
VFR levels however brief MVFR cigs will be possible especially at
PUW and COE. Any MVFR cigs which form will likely erode before the
end of the forecast period. For tomorrow morning the main concern
will revolve around increasing winds behind the front. Gusts of 25
kts will be possible with even stronger values after 18z. fx

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        44  57  36  54  37  60 /  60  20  10  20  20   0
Coeur d`Alene  43  56  35  53  37  59 /  80  50  10  30  20  10
Pullman        45  56  36  53  37  58 /  70  50  10  10  20  10
Lewiston       49  62  40  59  42  64 /  50  30   0  10  20   0
Colville       43  59  37  58  37  63 /  40  30   0  30  30   0
Sandpoint      40  54  35  53  35  58 /  90  70  10  30  30  10
Kellogg        40  51  34  49  36  55 /  90  90  20  30  40  20
Moses Lake     47  63  39  63  39  67 /  10   0   0  10   0   0
Wenatchee      45  59  40  61  41  66 /  10  10   0  10  10   0
Omak           43  62  39  61  38  66 /  10   0   0  10  10   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

$$



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