Area Forecast Discussion
Issued by NWS Spokane, WA

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806
FXUS66 KOTX 102337
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
337 PM PST WED FEB 10 2016

.SYNOPSIS...
High pressure weakens over the next couple of days, allowing for
increasing precipitation chances. A warm front Thursday, followed
by a cold front passage Friday, will produce light valley rain
and high mountain snow across much of the region. Unsettled
weather will continue through the weekend into early next week
with valley rain, high mountain snow and breezy winds expected.
Temperatures will be quite mild on Monday with many locations
seeing highs in the mid 50s to low 60s.

&&

.DISCUSSION...
Tonight: A weak cold front will push across the region this
evening and is already beginning to push east of the Cascades this
afternoon. Radar did pick up on some light rain west of the
Cascades earlier in the day. Lower levels are a bit drier on this
side of the Cascades, so I do not expect the same kind of radar
returns as moisture increases. Expect mainly very light precip or
sprinkles/high mountain flurries for the evening. Upslope flow
into the Panhandle will keep a small chance for showers through
the night.

Thursday and Thursday night: A warm front will push in over the
region behind the cold front passage tonight. This front will
result in a resurgence of moisture into the region and will have
access to a better moisture tap. In fact, this higher moisture
content is noticeable on water vapor imagery with better
enhancement out at around 36N and 136W in the eastern Pacific.
Most areas will see light precipitation with the Cascades seeing
the best chances in the afternoon and then shifting over to the
Panhandle overnight. Snow levels will remain relatively high with
mainly valley rain and high mountain snow. The one exception to
this will be possibly up the Methow Valley. The NAM model in
particular shows a nearly isothermal profile right along the 0
degree line from the surface up to around 5,000 ft MSL. Really
tough to say if this will translate as snow or rain for places
like Winthrop and Mazama. It will likely depend on how much these
locations can warm up through the day on Thursday as the steadier
precip likely will not get going until the afternoon hours.

Temperatures will generally remain above normal. Nighttime
temperatures will feel quite mild, especially Thursday night as
warm air advection and cloud cover will yield lows in the mid to
upper 30s for many locations. /SVH

Friday through Wednesday...A wet, but warm pattern will set up
over the region through this portion of the forecast. A cold
front will move through the Inland Northwest Friday afternoon,
resulting in a good chance for showers. Then the flow becomes
westerly through the weekend and into next week with a series of
weak frontal boundaries that will keep conditions unsettled.

Friday and Saturday...Model guidance is pretty similar showing
a cold front moving into the Cascades around late morning, then
moving slowly through the forecast area Friday afternoon/evening
and should be well east of the area by early Saturday morning.
Ahead of the front good isentropic lift and deep Pacific moisture
will result in widespread stratiform precipitation. As the front
moves through the area we expect drying from the west, with
precipitation turning showery near the Cascade crest and for the
Panhandle mountains. Snow levels start out between 5000-7000 feet,
but will drop with the frontal passage down to 3000-4000. This
will mean high mountain snow and low elevation rain. QPF totals
through Saturday afternoon will range from around a tenth to a
quarter of an inch for the lowlands and a quarter to a half inch
for the mountains, and locally a little more. Snow amounts for the
higher elevations look to be 2-5 inches. Winds with and just
behind the cold front Friday night and Saturday will increase out
of the southwest 10-15 mph with gusts 20-25 mph. Temperatures will
be in the upper 30s to upper 40s and on the warm side of normal.

Sunday through Wednesday...The active weather will continue through
the end of the forecast period. Rain and snow will be in the
forecast just about every day. The exception may be Tuesday when
another fast moving ridge moves through the region. But this will
be short lived. After Sunday morning snow levels will remain high
above 5000-5500 feet, so precipitation as low elevation rain and
high mountains snow. Temperatures will climb into the 50s to low
60s Monday and Tuesday, before cooling off on Wednesday.

One thing we will be keeping an eye on will be breezy/gusty winds
on Monday with southwest winds 15-20 mph and gusts 25-30 mph. The
combination of the warm temperatures mentioned above, high dew
points and breezy winds is a great pattern for rapid snow melt,
especially at the lower and mid elevations. Snow melt will likely
result in rises on small rivers and streams. Flooding is not
expected at this time. However, run-off may fill up road side
ditches etc, and result in ponding and the potential for low water
crossing in areas that have substantial low elevation snow. For
example the Waterville Plateau, The Methow valley, and some of the
northern mountain valleys. This will be monitored through the
weekend so stay tuned. Tobin

&&

.AVIATION...

00Z TAFS: A weak wave will cross the Inland NW this evening,
while a more organized warm front lifts into overnight into
Thursday. Mainly middle to high clouds pass early this evening,
with a sprinkle threat near the eastern TAF sites. Any clearing
that may develop, along with a south to southeast flow in the
boundary layer, will bring a threat of MVFR/IFR stratus toward mid
to late evening or overnight. At the same time the middle to high
clouds associated with the warm front will start to invade. If
these are slower thicken there could be some IFR/LIFR fog. However
confidence is low. As the warm front continues to lift in Thursday
morning the threat of -ra/-shra will come in. The chances will
arrive near EAT/MWH first and toward the GEG/SFF toward midday or
early afternoon. However the overall best threat of precipitation
will remain near EAT. /J. Cote`

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        34  46  38  48  34  45 /  10  20  70  70  70  40
Coeur d`Alene  34  46  38  47  36  44 /  10  20  70  70  80  60
Pullman        40  51  42  52  37  47 /  10  10  20  50  60  40
Lewiston       44  55  44  57  41  53 /   0  10  20  40  50  40
Colville       33  41  35  42  33  42 /  10  20  80  60  70  50
Sandpoint      33  43  36  43  34  41 /  10  20  90  70  90  60
Kellogg        36  43  37  44  35  39 /  20  20  70  60  90  80
Moses Lake     33  46  37  48  34  49 /   0  20  40  50  30  10
Wenatchee      33  40  35  44  32  45 /  10  60  80  40  30  10
Omak           30  37  34  38  30  41 /  10  40  80  40  30  20

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until 10 AM PST Saturday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$



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