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Area forecast discussion 
National Weather Service Spokane Washington
420 am PDT sun Apr 19 2015

Synopsis...
warm, dry weather is expected through Tuesday. Temperatures are
expected more than ten degrees above average. The arrival of a
cold front as early as Tuesday night will bring the first threat
for showers and cooler temperatures. After this, a number of
waves track across the inland northwest through at least Sunday.
With all of these, the heaviest amounts of rain will fall across
north Idaho, with snow levels high enough to not pose a threat to
any regional passes. Isolated thunder also is possible with each
of these waves.

&&

Discussion...
today through Monday night: a ridge of high pressure will promote
dry and mild conditions, with occasional high clouds. This morning
WV/infrared satellite shows the region in a northerly flow, with the
ridge axis just off the Pacific coast. Over the next 48-hours the
ridge axis slowly migrates inland and toward north Idaho. With
only minor mid-level ripples in the flow and no deep moisture,
this will bring dry conditions. Expect some periods of high
clouds, especially this morning and early afternoon and again
Monday morning and afternoon base on current model depictions,
along with some spotty flat cumulus around the mountains each
afternoon in the heating of the day. As for temperatures a
thermally induced pressure trough develops through early this
week, centered first toward western Washington and the Cascades, then
gradually shifting later Monday (into tuesday). This will support
a warming trend, with afternoon highs some 7-10 degrees above
average today and 9-13 degrees above normal on Monday. This
translates to many areas outside of the mountains seeing highs in
upper 60s to lower 70s. /J. Cote'

Tues through sunday: upper short-wave ridging over a northward-
surging thermal ridge tues will help to produce well above normal
high temperatures in the 70s for most towns. A few 80s will be
possible for the Columbia Basin as well as the Lewiston and
Colville areas. We're fairly confident that late tues will be the
first chance of showers and organized thunder, first developing
along the Cascades then advancing north overnight. Following this
is the most uncertain part of the fcst as an approaching north-
south shearing upper trough reaches the Cascades Wed, with a
series of subsequent short-waves/frontal passages tracking across
the pac NW the rest of the week. Again...there are still big
enough inconsistencies in timing, position and evolution of these
waves that we continued with a conservative modification of the
fcst, keeping the threat of showers in the fcst each day through
the weekend. The GFS and European model (ecmwf) agree that one of the stronger
frontal passages will move through on Sat, followed by a short
break, then a much more moist fetch with a late Sunday or Sunday
nt front. Snow levels will remain high enough to not pose a
threat to the passes. Thunder is not out of the question each day
for essentially all zones. Bz

&&

Aviation...
12z tafs: high pressure building into the region will result in
VFR conditions. Winds will remain weak and some passing high
cirrus can be expected to drop south into the region out of British Columbia.
/J. Cote'



&&

Preliminary point temps/pops...
Spokane 67 42 70 45 75 50 / 0 0 0 0 0 10
Coeur D'Alene 67 37 70 41 75 44 / 0 0 0 0 0 10
Pullman 66 39 69 40 74 46 / 0 0 0 0 0 10
Lewiston 71 44 73 46 78 49 / 0 0 0 0 0 10
Colville 71 40 74 41 78 46 / 0 0 0 0 0 10
Sandpoint 65 35 68 37 74 40 / 0 0 0 0 0 10
Kellogg 66 37 69 39 75 43 / 0 10 0 0 0 10
Moses Lake 72 42 75 43 79 50 / 0 0 0 0 0 10
Wenatchee 73 48 77 50 77 53 / 0 0 0 0 10 20
Omak 73 42 76 43 76 47 / 0 0 0 0 10 20

&&

Otx watches/warnings/advisories...
Idaho...none.
Washington...none.
&&

$$

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