Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 241221
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
520 AM PDT FRI OCT 24 2014

.SYNOPSIS...
Breezy and unsettled conditions will continue for the rest
of today but be on the decrease tonight and into tomorrow. This is
only temporary as rain is expected to return Friday night and
Saturday. A strong cold front passage Saturday Night and Sunday
will produce very windy conditions with gusts in excess of 40 mph.
The pattern will continue to be active into early next week. This
includes the potential for widespread rain into early next week as
moisture associated with former typhoons makes its way toward the
Pacific Northwest.

&&

.DISCUSSION...
Today through Tonight...Looks like this period will see a little
break in the action in regards to our recent string of wet weather.
The anomalously moist atmospheric river has temporarily dipped
south of our forecast area. As of 2am...about the only weather
action was a blanket of high level moisture covering most of the
region. This cloud cover was associated with the 130-150kt upper
level jet. This dry respite will gradually come to an end this
morning in response to deep upstream trough centered near
35n/139w. Models in good agreement that as this trough moves
closer to the coast...the atmospheric river will buckle northward
as a warm front and push steadily across the Oregon/Washington
border. This transition will be accompanied by backing mid-level
flow (southerly winds)...leading toward a significant increase in
isentropic ascent and moisture advection. This will result in an
increasing chance of precipitation. By midday most of the
precipitation will be just south of our forecast area...however
some light rain could creep into the Blue Mountains and Camas
Prairie. By the latter half of the day...there is good model
agreement that the northern edge of the preciptiation will lie
approximately from Pullman to Moses Lake.

The front will continue to surge northward overnight...reaching
the Canadian Border well after midnight. Based on the good
moisture availability and moderate isentropic ascent...most areas
will receive some precipitation. Confidence is highest however
near the Cascades...as the 850-700 mb layer takes on a well
defined southeast-east wind regime. This will lead to good
orographic ascent which will only be bolstered by strong
divergence aloft. Categorical pops will be justified for locations
west of a Republic to Wenatchee line...and QPF totals will likely
range from a quarter to half inch. Snow levels will likely be
fairly high...ranging from 5.5-6k feet. This should not pose any
travel problems...however some snow can be expected to fall late
tonight over the highest parts of the North Cascades Highway.
While the precipitation really gets going late tonight over
locations near the Canadian Border...it will begin to taper off
near the Oregon border as the dry slot move in behind the warm
front. fx

Saturday through Monday Night: An upper level trough and surface
low will approach the southern Oregon coast Saturday. This weather
disturbance will bring an increase in cloud cover through the day.
As the surface low moves up the coast through the day and then
pushes inland through the evening our chance of precipitation will
increase. Have increased chance of precipitation for most
locations as many locations should receive at least 0.01 of
precip as this feature moves through. Even normally dry locations
such as the basin and east slope of the Cascades valleys could see
rain given the decent southeast upslope flow ahead of the cold
front.

...Breezy to windy conditions expected Saturday Night and Sunday...

Winds  associated with the cold front will be quite strong.
Saturday evening southerly winds 10 to 20 mph will be common
across most of the Columbia Basin and into the Palouse and
Spokane/CDA areas. Those winds will increase through the overnight
hours and into Sunday morning to 20 to 30 mph with gusts to 40 or
45 mph. Right now the strongest winds look to stretch from the
Blue Mountains up through the Palouse. Winds will slowly decrease
through Sunday afternoon and into the evening hours as the surface
low weakens and continues to move east across southern Canada.

Sunday the chance of precipitation will decrease through the
evening hours. The exception to this will be the Cascade crest and
ID Panhandle where showers will likely continue. A flat ridge
moves into the Inland Northwest Monday ahead of the next
potentially big soaker. Chance of precip will increase through the
overnight hours and into Tuesday morning, especially along the
Cascade Mountains and nearby valleys as the next weather system
moves onto the west coast.

Temperatures will start out at or above average on Saturday and
then drop to near average readings by Sunday and then to slightly
below average readings by Monday. /Nisbet

Tuesday through Thursday: The models are depicting a shortwave
trough pushing through the region followed by a weak ridge
building into the region for this period. For Tuesday, widespread
rain is expected in the morning. Precip chances will decrease from
West to East as the period progresses into Wednesday leaving only
the Idaho Panhandle with high potential to receive rain. Model
agreement on Thursday is not high but they are indicating a Low
in the Gulf of Alaska beginning to press into the Pacific
Northwest and bringing some precip to the Cascades. Light winds
associated with this pattern has potential for morning fog int he
northern valleys. Temperatures will still be above normal with
highs in the mid 50s to low 60s and lows in the upper 30s to mid
40s. /JDC

&&

.AVIATION...
12Z TAFS: VFR conditions expected at all forecast sites through
00z although cigs will steadily lower through the day ahead of
incoming warm front. The front will develop a east-west band of
rain which will hit LWS MWH EAT and PUW around 00z and push into
the GEG SFF COE area around 02z. Once the rain begins...we expect
to see some clouds develop below 030 but we don`t expect prevalent cigs
at MVFR levels. The one exception will be at EAT due to proximity
to Cascades combined with upslope flow. The warm front will
deliver about 6 hrs of precipitation to most sites (persisting a
little longer at EAT) with improving conditions after that. fx

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        55  44  65  43  52  36 /   0  60  30  80  30  10
Coeur d`Alene  55  42  65  42  51  34 /  10  50  30  90  30  20
Pullman        55  45  68  42  49  38 /  30  50  20  80  30  20
Lewiston       59  44  72  47  56  41 /  40  50  10  60  20  20
Colville       54  42  62  45  52  35 /  10  70  30  80  50  20
Sandpoint      53  40  61  42  48  34 /  10  70  30  90  50  30
Kellogg        52  41  64  40  45  34 /  10  60  20  90  40  30
Moses Lake     57  45  60  45  59  37 /  10  80  20  30  10  10
Wenatchee      57  44  57  43  55  38 /  10  80  60  40  10  10
Omak           56  42  55  43  54  35 /  10  90  50  50  30  10

&&

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




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