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Area forecast discussion 
National Weather Service Spokane Washington
252 PM PDT Thursday Oct 8 2015

cloudy skies remain as weak high pressure builds into the area.
The weather becomes more active over the weekend, with periods of
rain and breezy to windy conditions. The threat of showers largely
retreats to the mountains early next week.



Tonight through Friday night...ridge of weak high pressure cluttered
with moisture some lingering moisture from yesterdays rainfall
along with middle and high level moisture streaming up through the
west side of the ridge and over eastern Washington and northern
Idaho is likely to keep a good portion of the evening rather
cloudy. Some weak ridge amplification takes place to displace
enough of the moisture streaming through it up to the north so
that only minor pops for light rain remain near the the north and
west. There is a possibility that low clouds and fog may again
form as boundary level moisture remains high and the low level
flow switches slightly to push it back to the east as dew points
remain quite high. Overnight low temperatures for the next night
or two in fact should remain on the warm side of normal given this
pattern inhibiting effective radiational cooling at night. Friday
into Friday night the ridge axis gets pushed into northwest
Montana and this allows disturbances running along the west side
of the ridge tied into the moisture draped along it to have a
better possibility of producing some rainfall as they move across
the ridge, but this is mostly for locations north of I-90 on
Friday. Friday night this rain potential expands further east and
south but may only extend a few miles south of I-90. /Pelatti

..gusty winds Saturday night...

Saturday through sunday: a dynamic upper level shortwave trough of
lower pressure will swing across the region Saturday night. The
cold front associated with this system will produce gusty winds
across the region. Winds will increase through the afternoon on
Saturday, but expected to become quite gusty Saturday
evening/night with cold front passage. Winds at 850 mbs will be
right around 40 kts; however, the 12z GFS solution is on the
stronger end of the model guidance with 850 mb winds closer to 50
kts across the Palouse and into the NE blue mtns. The GFS also has
a tighter pressure gradient across the region compared to the NAM,
European model (ecmwf) and Canadian. I did not put in winds as strong as the GFS
would suggest, so there is the potential for even stronger winds
if this model ends up verifying. Sustained wind speeds of up to 25 mph
with gusts up to 45 mph are expected with frontal passage.
Stronger wind gusts will be possible in the mountains to around 60
mph. Any light weight items will be at risk of being blown around,
high profile vehicles may have some difficulties and localized
power outages from broken tree branches on power lines will be
possible with the winds.

There will also be a juicy p-wat plume (around 0.80 inches) ahead
of the front. This will result in an increasing chance for precip
late Saturday afternoon with best chances for the evening hours.
Strong westerly flow will limit precip accumulations in the Lee of
the Cascades and out into the western basin. Highest precip
accumulations will likely be over the Cascade crest and in the Idaho
Panhandle. The front will sweep across quickly, but is expected to
result in a brief period of more moderate rainfall rates right
along the front itself. Storm total rainfall is expected to range
between a tenth to a quarter of an inch from extreme eastern Washington
into the Idaho Panhandle. The higher terrain in the Idaho Panhandle will
likely see a bit more between a quarter of an inch to a half an
inch due to favorable upslope flow. Snow levels will fall quickly
behind the front as well across the east slopes of the northern
Cascades to around 5,000 feet. This is expected to result in a
couple of inches of snow accumulation above this elevations
primarily near the crest.

Sunday night and Monday night: there will be a break in the
weather Sunday night. Models then indicate the potential for a
much weaker system pushing across the region Monday into Monday
night. There is more model discrepancy with this weather system
than the weekend. This has resulted in lower confidence in the
details, but at least a chance of some rain and generally breezy
conditions can be expected. Typical autumn temperatures are
expected through the weekend into early next week. /Svh

Tuesday through thursday: this period is expected to be warm and
dry. A ridge pattern is going to dominate the region for the
extent of the period. The models are in good agreement with this
scenario. This will keep the region precip free. Temperatures are
the main impact for the region. The highs are expected to be near
5 to 10 degrees above the season normals for this time of year.
High temperatures are expected to be in the upper 60s to low 70s.
Lows are expected to be in the range of mid 30s to low 40s. /Jdc


18z tafs: abundant low level moisture under clouds streaming aloft
is keeping stratus and fog of various intensity in the aviation low as IFR to MVFR at times this morning. Southeast
winds later today will improve this but overnight after 10z Friday
into Friday morning more low clouds and fog will form, but not as
widespread or as intense in comparison to that which occurred this
morning. /Pelatti


Preliminary point temps/pops...
Spokane 53 72 53 71 50 62 / 0 10 20 20 70 20
Coeur D'Alene 52 74 51 72 49 61 / 10 10 20 20 70 30
Pullman 54 77 50 75 49 61 / 0 10 10 10 70 40
Lewiston 55 77 54 80 54 68 / 0 10 10 10 70 30
Colville 48 72 48 68 46 63 / 10 20 20 50 80 10
Sandpoint 49 72 48 69 47 60 / 10 10 30 30 80 40
Kellogg 51 72 49 71 47 57 / 10 10 20 20 80 60
Moses Lake 53 78 53 74 51 68 / 0 10 20 20 20 0
Wenatchee 53 75 55 72 48 67 / 10 10 30 20 20 0
Omak 52 73 51 67 43 64 / 20 20 20 30 20 0


Otx watches/warnings/advisories...


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