Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 101009

Area Forecast Discussion
National Weather Service Spokane WA
309 AM PDT SAT OCT 10 2015

Today will be quite warm with very windy conditions developing in
the late afternoon and lasting into the night. A fast moving cold
front will bring a good chance of rain to the region tonight.
The wind will decrease on Sunday, and precipitation will move out
of Washington and Idaho on Sunday as well. Mild weather is
expected to return for much of next week.




Today and Tonight: Wind Advisories remain in effect from Moses
Lake and the Waterville Plateau through eastern Washington and
the Idaho Panhandle. Winds are expected to peak along and behind a
strong cold front which will cross the Cascades late this
afternoon. The cold front will also bring showers and the
potential for embedded thunderstorms with the best potential for
thunderstorms along the Canadian border.

* Winds: Our forecast for wind speeds this afternoon into tonight
  hasn`t changed much. The NAM and GFS have remained fairly
  consistent with the late afternoon/early evening timing of the
  cold front. Pre-frontal south winds will increase by mid
  afternoon. Look for sustained south winds of 15 to 25 mph this
  afternoon with gusts to 35 mph over the Columbia Basin, West
  Plains and exposed mountain ridges of central Washington. As the
  cold front races across eastern Washington and north Idaho
  between 5 PM and 8 PM, we expect to become westerly and increase
  into the 20 to 30 mph range with gusts of 40 to 50 mph. The open
  wheat country from the Waterville Plateau to Spokane and Pullman
  will likely experience the most widespread windy conditions.
  Mountain ridges over the Idaho Panhandle will also experience
  windy conditions well through the night under stiff cold
  advection accompanied by winds of 35 to 45 mph in the 850-700mb

* Thunderstorms: Isolated thunderstorms have been added to north
  central and northeast Washington and the far northern Idaho
  Panhandle late this afternoon into the evening. The NAM progs
  several hundred J/KG of surface based CAPE in places like
  Republic, Colville, Spokane, and Bonners Ferry. We are certainly
  out of our peak thunderstorm season, but vigorous frontal
  forcing combined with rapid mid-level cooling may produce some
  widely scattered thunderstorms. Convective downdraft could have
  the potential to enhance our already windy conditions. Gusts
  exceeding 55 mph could be possible given the momentum above
  700mb and steep lapse rates.

* Impacts: Patchy blowing dust has been added to the forecast.
  Conditions in central and eastern Washington are not as
  favorable as they were a month ago. We have had some rain
  recently, and we are further removed from the planting season
  for winter wheat. However, blowing dust could still become a
  localized issue by early evening over the Columbia Basin,
  Waterville Plateau, West Plains and Palouse. Other wind impacts
  will be hazardous cross winds for high profile vehicles, and
  localized power outages. We may also see a higher risk for
  downed trees in our areas burned by summer fires.

* Rain Amounts: The fast frontal movement and the strong mid-level
  westerlies tonight should produce a rain shadow over central and
  eastern Washington. Our highest rain amounts will likely occur
  over the Cascade Crest with up to an inch and a half of rain in
  the high terrain. A secondary rain max with amounts up to a half
  inch possible for the mountains along the Canadian border of far
  northeast Washington and extreme northern Idaho. Our vulnerable
  burn scars in Okanogan and Chelan counties will probably receive
  a tenth of an inch of rain or less. The burn scar flooding
  threat looks very low.

Sunday and Monday: Much drier air will follow the passage of
Saturday night`s cold front. Rain chances will be limited to the
extreme eastern portion of Shoshone county on Sunday morning. The
wind should decrease Sunday morning as the surface pressure
gradient relaxes with the departing front. The mention of rain has
been dropped from all but the Cascade Crest for Monday. The latest
model runs shunt deep layer moisture into northern and central
British Columbia...well north of our region. It still looks like
Monday will be mostly cloudy with temperatures in the upper 60s to
low 70s. /GKoch

Monday night through Saturday: A weakening and shearing cold front
will be on the exit Monday night. This will result in a decreasing
trend of cloud cover and precip on Tuesday. Models are all in
good agreement that a strong ridge of high pressure will then
build in over the region for the remainder of the work week. This
will result in a warming trend with temperatures around 15
degrees above normal by Thursday and Friday. Models look to break
the ridge down at the end of this period some time around next
weekend. /SVH


06z TAFS: A strong cold front will result in gusty winds Saturday
afternoon and evening along with a brief threat for rain at the
TAF sites. The strongest gusts are expected at KMWH/KPUW/KGEG/KSFF/KCOE
with 35-42kt gusts expected. Otherwise mid and high clouds will
continue to stream into the region through Saturday morning ahead
of the approaching cold front. The NAM model shows the boundary
layer becoming saturated Saturday morning over northern Washington
and near the Cascades. There will be a brief chance for stratus
12-18Z Sat at KGEG/KSFF/KCOE/KMWH/KEAT but most likely VFR
conditions will continue.  JW


Spokane        73  48  64  44  68  48 /  20  60   0   0   0   0
Coeur d`Alene  73  47  64  41  68  46 /  10  60  10   0   0   0
Pullman        76  48  65  42  72  45 /  10  50  10   0   0   0
Lewiston       80  53  72  48  76  51 /   0  30  10   0   0   0
Colville       71  44  64  40  64  43 /  20  70  10   0  10  10
Sandpoint      69  47  65  36  65  42 /  20  60  10   0  10  10
Kellogg        71  46  60  41  67  45 /  10  70  30   0  10   0
Moses Lake     74  47  70  42  73  47 /  10  30   0   0   0   0
Wenatchee      71  48  70  50  72  54 /  20  20   0   0   0  10
Omak           71  43  67  45  67  49 /  50  30   0   0  10  10


ID...Wind Advisory from 2 PM this afternoon to 1 AM PDT Sunday for
     Coeur d`Alene Area-Idaho Palouse.

     Wind Advisory from 2 PM this afternoon to 5 AM PDT Sunday for
     Central Panhandle Mountains-Northern Panhandle.

WA...Wind Advisory from 2 PM this afternoon to 1 AM PDT Sunday for
     Lower Garfield and Asotin Counties-Northeast Mountains-
     Spokane Area-Washington Palouse.

     Wind Advisory from 2 PM this afternoon to 5 AM PDT Sunday for
     Northeast Blue Mountains.

     Wind Advisory from 2 PM this afternoon to 11 PM PDT this evening
     for Moses Lake Area-Upper Columbia Basin-Waterville Plateau.


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