Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 030423
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
923 PM PDT TUE SEP 2 2014

.SYNOPSIS...
A deep low pressure system will bring showers and isolated
thunderstorms to most of the Inland Northwest through Wednesday
especially over northern Washington and the Idaho Panhandle.
Thursday morning will be cold with low temperatures down into the
lower to mid 30s for the mountain valley locations. The return of
high pressure Thursday through the weekend will bring several days
of dry weather, light winds, and warmer temperatures.

&&

.DISCUSSION...
As of 9 pm...radar indicated a potent closed low centered near
Mount Baker in the North Washington Cascades. Models are in good
agreement that this low will track east into the Northeast
Washington Mountains and North Idaho Panhandle tonight. As it does
so mid level cooling will be significant with 500mb temps falling
from -15 to -18C this evening to -19 to -21C overnight. This will
result in increased mid level instability resulting increasing
showers and isolated thunderstorms. The NAM shows elevated CAPE
values of 200-500 J/KG with the highest values near the Canadian
border. The track of the low will favor widespread showers over
the northern mountains...with numerous showers as far south as
Spokane/Coeur D`Alene. A dry slot coming around the low over
southern Washington should keep shower coverage isolated over the
Blue Mountains, Lewiston area, and Camas Prairie. Strong
downslope westerly flow off the Cascades will also keep coverage
isolated around Wenatchee and Moses Lake. With colder air moving
into the region tonight and 850mb winds of 25-35 kts gusty winds
are expected to continue.

On Wednesday as the low moves into Northwest Montana a band of
wrap around rain is expected over Northeast Washington into the
Idaho Panhandle. With good model agreement as well as upslope
winds into the higher terrain have increased POPS to near 100
percent for places like Sandpoint, Coeur D`Alene and Kellogg.
Cloud cover and showers look to persist through the day. The 00z
GFS and 12z ECMWF show 850mb temps only rebounding to
6-8C...suggesting a chilly day with mountain highs in the
40s...with 50s in the valleys. Temperatures have been cooled
slightly from Colville to Spokane east to the Idaho/Montana
border. JW

&&

.AVIATION...
00Z TAFS: A strong cold front will cross east of the Cascade Mtns
between 0-6z this evening. This front will produce gusty winds
from the west and will arrive at KEAT and KMWH between 00-02Z and
then push into the KGEG, KSFF, KCOE, KPUW and KLWS TAF sites
around 03-05Z. Blowing dust is possible around KMWH. Winds will
remain breezy through the overnight hours. Showers and
thunderstorms are expected across the northern mtns early this
evening into tonight with a few storms as far south as
KGEG/KSFF/KCOE. A band of wrap around moisture and upslope flow
into the Idaho Panhandle on Wednesday will produce steady rain and
MVFR conditions with some improvement likely in the afternoon.
Occasional MVFR conditions is possible at KGEG/KSFF Wednesday
morning depending on how far west the band of wrap around rain
extends. JW

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        49  62  47  74  49  79 /  60  50  20   0   0   0
Coeur d`Alene  48  58  43  74  44  79 /  70  90  40   0   0   0
Pullman        48  63  41  74  43  81 /  20  30  10   0   0   0
Lewiston       54  71  50  79  51  85 /  10  10  10   0   0   0
Colville       49  64  40  77  41  82 /  90  70  30   0  10  10
Sandpoint      47  57  40  72  40  76 /  90 100  60  10  10  10
Kellogg        45  54  40  70  43  75 /  50 100  50  10   0  10
Moses Lake     53  76  49  79  49  85 /  20  10   0   0   0   0
Wenatchee      52  76  55  78  54  84 /  20  10   0   0   0   0
Omak           53  73  47  79  48  84 /  50  10  10   0   0   0

&&

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

$$




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