Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 231902
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1102 AM PST Thu Nov 23 2017

.SYNOPSIS...
Wet and unsettled weather will linger through the week as a
series of storm systems brings several rounds of precipitation to
the region. Snow levels will be quite high through today allowing
motorists to travel over mountain passes on wet pavement. Cooler
and unsettled conditions this weekend will result in lowering
snow levels just as travelers are heading home this weekend. Windy
conditions are expected today across the exposed areas of the
Basin, Palouse, and north into the Spokane-Coeur D`Alene area.

&&

.DISCUSSION...
Morning update: Quite the range of weather impacts possible today.

Current: The atmospheric river currently streaming over the
region has resulted in very mild conditions and heavy rainfall for
the Cascade Crest. Close to 1.50" inches of rain fell in the Stehekin
River basin, has worked through the system and resulted in minor
flooding. The river looks to have crested but will remain in flood
status until the cooler air arrives tonight.

Winds: We have made some changes to the wind highlights to expand
into the Idaho Panhandle. The wind threat will be in two waves.
The gradient driven winds which prompted our initial wind advisory
issuance on Wednesday will bring winds across the open Columbia
Basin, Palouse, West Plains and adjacent Idaho zones. After
analyzing this morning`s models, particularly hi-res, this mild
air mass combined with cooling aloft and strong forcing will
promote line of showers and thunderstorms in the afternoon and
very early evening. This will bring the potential for deeper
mixing of winds to the surface with the focus across the Idaho
Panhandle and far eastern reaches of Washington. This carries
higher uncertainty but given the adequate sunbreaks on satellite
and agreement amongst numerous hi-res members including the HRRR
and local 1KM OTX, opted to expand the wind advisory for this
reasoning. There will be several lines of convection that may
occur through the afternoon. It is not out of the question that a
few storms produce sporadic winds in the 55-60 mph range but this
should not be widespread and will handled with short-term products
as the event unfolds.

Weather: Thunderstorms were added to Ern WA and N ID for this
afternoon.  /sb

&&

.AVIATION...
18Z TAFS: Strong winds will impact the eastern terminals today.
Gusts of 30 to 45 mph will be common. Brief gusts to 55 mph are
possible with any lines of showers or thunderstorms that develop
between 22-01Z. This was represented in the TAF with tempo
groups. It is a different story in Central WA which is dealing
with decoupled atmosphere, on and off low clouds/fog. This looks
to only be an issue through 20z. Winds will remain breezy
overnight but decrease with time. Stratus is expected to redevelop
across NE WA and N ID while patchy fog redevelops vcnty
KMWH/KEAT. /sb

&&

.HYDROLOGY...
Flood watch has been dropped for Paradise Creek. The basin had no
issues with the last pulses of rain and should be able to take on
the quarter of an inch expected today. Stehekin River is flooding.
Cooler air arrives in the Cascades this evening and will decrease
snow ripening/melt. However the river may be slow to fall below
flood stage with additional rain showers expected along the Crest
today then mix of rain and mountain snow overnight. Additional QPF
amounts today will be around half an inch with an addition quarter
to four tenths possible overnight, pending where the Puget Sound
Convergence Zone sets up.  /sb

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        59  36  46  32  45  42 /  80  20  10  10  10  50
Coeur d`Alene  57  36  44  32  45  40 /  70  50  10  10  10  50
Pullman        59  37  47  34  49  46 /  90  80  10   0  10  30
Lewiston       63  39  51  36  52  49 /  90  90  10   0  10  30
Colville       55  34  44  32  43  37 /  80  30  10  20  10  60
Sandpoint      57  35  42  30  42  38 /  90  50  30  20  10  60
Kellogg        56  34  41  31  44  41 / 100  70  30  10  10  40
Moses Lake     62  35  50  31  44  41 /  20   0  10  10  30  40
Wenatchee      57  36  48  33  41  35 /  50  10  10  10  50  70
Omak           55  34  45  33  41  35 /  40  10  10  10  20  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 6 PM PST this evening for Central Panhandle
     Mountains-Lewis and Southern Nez Perce Counties-Lewiston
     Area-Northern Panhandle.

     Wind Advisory until 6 PM PST this evening for Coeur d`Alene Area-
     Idaho Palouse.

WA...Wind Advisory until 6 PM PST this evening for Lower Garfield and
     Asotin Counties-Spokane Area-Upper Columbia Basin-
     Washington Palouse.


&&

$$


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