Area Forecast Discussion
Issued by NWS Spokane, WA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KOTX 302347
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
446 PM PDT TUE SEP 30 2014

.SYNOPSIS...
Scattered showers and breezy conditions will come to an end
tonight. High pressure will gradually build in through the weekend
and linger into the middle of next week. This will result in
generally dry weather with temperatures warming to above normal by
the weekend.


&&

.DISCUSSION...
Tonight and Wednesday: An upper level trough will pivot through
eastern Washington into north Idaho this evening. As it does, it
will bring a chance of showers to the northern mountains, northern
Columbia Basin and most of north Idaho. A few embedded
thunderstorms are possible through late this afternoon. This
convection will be diurnally driven and the clouds with showers
will decrease rapidly with the loss of daytime heating early this
evening. Westerly winds will remain gusty from the lee of the
Cascades and across the lower Columbia Basin with speeds of 20 to
25 mph. By tonight, the flow aloft becomes northerly and drier. A
ridge of high pressure building off the Washington coast, will
push inland on Wednesday and give drier and sunnier conditions.
Temperatures will cool slightly overnight into the upper 30s to
lower 40s. And in sheltered areas, expect even cooler conditions
under the clearing skies. Anticipate some patchy fog in many of
the northern valleys, especially in the locations that the showers
tracked through today. The fog will be short lived and expect
mostly sunny skies for the rest of the day under lighter winds.
Daytime temperatures will continue to be cool, remaining at or
slightly below normal./ rfox

Wednesday Night through Saturday: A flat ridge of high pressure is
expected to bring a prolonged period of dry weather and mild
temperatures to the Inland Northwest from mid-week through the
weekend. The 12z model runs are in decent agreement that the polar
jet will remain far enough north through the second half of the
week that precipitation chances will be largely north of the
Canadian border. Slight chances for rain are in the forecast for
the northern Cascades and the high terrain along the Canadian
border for Friday and Saturday, but nearby valley locations should
remain dry. Look for a gradual warming trend Thursday through
Saturday with temperatures climbing a bit above average by the
weekend. /GKoch

Saturday night through Tuesday...An upper ridge over the western
U.S. is expected to remain strong enough in the extended forecast
period to deflect a moist zonal flow north of the area across
Central British Columbia. The GFS, ECMWF, and Canadian models are
in good agreement with this idea.  The Inland Northwest will be
the warm and stable side of the jet stream. Models show some
increase in lower level moisture during the period as some of the
very moist flow over British Columbia clips the area. This will
raise dew points into the 40s to lower 50s which will aid in mild
night time lows. Periods of mid/high clouds may also assist with
warmer nights. In addition...850mb temps in the 14-17C range will
result in valley highs mainly in the 70s with a few lower 80s in
the warmest spots such as Wenatchee, Moses Lake, and Lewiston. The
increased low level moisture content and upslope westerly flow may
be enough to ring out a few light showers near the Cascade crest
and in the mountains of North Idaho...with the better chances
north of the Canadian border. JW

&&

.AVIATION...
00Z TAFS: An upper trough and associated cold pool aloft has
destabilized the atmosphere, allowing scattered showers and
isolated thunderstorms to develop across much of eastern WA and
north ID this afternoon that will persist until 02z. Some of the
strongest cells may produce occasional lightning and brief heavy
downpours. As the sun sets, skies should clear quickly with the
loss of afternoon heating. Clearing skies and diminishing winds
overnight may produce low status at KGEG/KSFF/KCOE and possibly
KPUW. Most likely to be affected is KCOE where greater amounts of
precip will provide a source of low level moisture. Any stratus
that develops will dissipate by 19Z. Winds may again become gusty
after 19Z Wednesday. /EK

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        41  62  40  64  42  70 /  20   0   0   0   0   0
Coeur d`Alene  41  62  41  64  40  70 /  30   0   0   0   0   0
Pullman        39  63  38  65  39  72 /  20   0   0   0   0   0
Lewiston       46  69  46  70  45  77 /  20   0   0   0   0   0
Colville       38  67  39  68  38  72 /  20   0   0   0  10  10
Sandpoint      39  60  37  62  35  66 /  50   0   0   0   0  10
Kellogg        39  55  40  60  40  65 /  60  10   0   0   0   0
Moses Lake     41  70  40  69  40  75 /   0   0   0   0   0   0
Wenatchee      47  69  46  69  48  74 /   0   0   0   0   0   0
Omak           40  67  39  67  44  74 /  10   0   0   0  10  10

&&

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

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.