Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 231205
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
504 AM PDT TUE SEP 23 2014

.SYNOPSIS...
Warmer than normal temperatures are expected again today, but
fall type weather is on the way for the middle to end of the week.
A slow moving cold front will bring an increased chance of rain to
central Washington on Wednesday and Thursday. Cooler temperatures
will also accompany the cold front Thursday and Friday. A slight
warming and drying trend is expected to occur next weekend.

&&

.DISCUSSION...
Today: Broad southwest flow will prevail as a closed low near 140W/46N
approaches the Canadian coast. Many pieces of energy will move
through the Inland Northwest through the next 48 hrs bringing an
increased chance of precipitation. One wave is exiting the Idaho
Panhandle now...another is moving across western WA this morning
and will clip our northern Cascade mountains...and yet another is
currently over western Oregon and will move in early this
afternoon. Decent mid level instability has kept some isolated
thunder going through the night across northeastern Oregon and
into the central ID Panhandle as well as a little pocket north of
Republic in the Okanogan Highlands. The threat of showers and
thunderstorms will continue through the morning hours...mainly for
southeast WA and the ID Panhandle. Then this afternoon the threat
mainly gets pushed into the mountains of ID and WA. Temperatures
today will be above average.

Tonight through Wednesday Night: The low remains off the coast
with southwest flow continuing. Waves will move through continuing
the threat of showers. Given the proximity of the low, models seem
to agree that there will be a line drawn from the Canadian/ID/WA
border down through Spokane to Ritzville and the Tri Cities. Areas
west of this line will see mostly cloudy skies with a good chance
of rain and daytime temperatures below average. East of this line
will be mostly dry with partly cloudy skies and temperatures at or
slightly above average. Given there hasn`t been a significant
modification of the air mass (no cold front yet) min temperatures
will be above average for this time of the year given the cloud
cover expected. /Nisbet

Thurs through Tues: Based on the preferred GFS, and not the ECMWF
model for the medium and extended range fcst, it`s not until
Thurs afternoon that the first vort max is ejected from the stnry
trough and moves through Oregon and into the Idaho Panhandle that
the front shows Ewd movement and helps to produce scattered
showers for much of Ern Wa and N Idaho. Once this wave moves out
of the area, the entire upper trough translates E and weakens
further, putting only SE Wa and the Camas Prairie of Idaho under
the threat of lingering showers as what`s left of a subtle
deformation axis tries to produce a narrow corridor of banded
pcpn. This is very similar, dynamically, to what the GFS was
showing the last few runs. The GFS guidance then strengthens and
stalls the upper low over Srn Idaho/Nrn Nv/Nrn Utah as another
speed max digs into the base of this trough, cutting it off from
the main belt of the westerlies to the north Sat and Sunday. As a
broad upstream upper trough in the Gulf of Alaska reaches the
Cntrl coast of BC, the Srn Idaho stalled wave ejects NE through
the Nrn Rockies, as brief short-wave ridging transitions to dry NW
steering flow over the region. bz

&&

.AVIATION...
12Z TAFS: A couple weather disturbances will pass through the
Inland NW over the next 24 hours. The 1st disturbance is moving
through the ID Panhandle, with sct -shra and isold -tsra.
A brief lull is expected in the mid to late morning, before the
second disturbance approaches in the afternoon and keeps the
threat of showers alive. VFR conditions are projected, but lcl
MVFR conditions possible in any heavier showers. For the next
24-36 hrs moderate to heavy rain will fall at times in the
Cascades with MVFR conditions expected.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        75  57  69  52  73  47 /  30  10  30  20  20  30
Coeur d`Alene  76  54  75  50  73  47 /  30  10  20  20  20  30
Pullman        78  54  78  49  73  48 /  10  10  10  10  20  30
Lewiston       82  60  86  56  79  54 /  10  10  10  10  20  30
Colville       77  53  60  50  75  43 /  30  20  60  40  50  40
Sandpoint      74  49  74  47  74  44 /  40  20  30  20  20  40
Kellogg        73  55  80  50  74  45 /  30  10  10  10  20  40
Moses Lake     77  57  68  53  73  46 /  10  20  50  40  50  20
Wenatchee      76  61  66  57  70  50 /  30  30  50  40  50  20
Omak           75  56  67  53  73  44 /  30  30  60  40  50  40

&&

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



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