Weather Service Report


894 
FXUS66 KOTX 270914
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
213 AM PDT MON APR 27 2015

.SYNOPSIS...
High pressure will build into the region today and linger through
Tuesday for a couple of days of nice weather. Between Tuesday
night and Thursday a weather disturbance will bring more seasonal
temperatures, breezy conditions and a threat of showers, followed
by a general drying trend by the weekend.


&&

.DISCUSSION...

Today through Tuesday...Narrow and slightly positively tilted
ridge of high pressure amplifies into the region allowing for a
continuation of the warming and drying trend with temperatures
peaking on Tuesday. Forecast temperatures are well above normal
Tuesday. A quick look at climo records show that most record high
temperatures for Tuesday are in the 80s and 90s so no sites are
expected to be near record highs, at least at this point in time.
/Pelatti

Tuesday night through Wednesday night...An upper level trough will
track through the PAC NW during this time frame. Some minor
timing issues but it looks like the associated cold front will
move across the Cascades late Tuesday evening then track quickly
east and be along the ID/MT border right around mid-day Wednesday.
Model guidance is similar showing a brief increase in moisture
with the frontal passage. This will lead to a very good chance
for showers and breezy/gusty winds with the front. The NAM and to
a lesser extent the GFS models are showing a pretty decent
increase in mid and upper level instability with fropa. Forcing
with the front should be quite adequate to lift parcels into this
unstable layer. I went ahead and pushed the timing of the
thunderstorms to coincide with the front between 06z-18z. While
the atmosphere will remain unstable through sunset Wednesday
evening it looks like surfaced based convection Wednesday
afternoon will not be deep enough to support anything more than
showers. Temperatures will take about a 8-12 degree drop putting
temperatures back near normal. Surface pressure gradients will
increase to 10-12mb with 850mb winds between 20-30kts. These winds
should be able to mix down to the surface with and behind the cold
front. With the front coming through at night winds may not reach
the same velocities if it came through during the day. But still
breezy/gusty winds will be common east of the Cascades overnight
and through the morning hours, before decreasing in the
afternoon.

Thursday through Monday the upper pattern will be zonal (west-east
winds) with what looks like a few weak waves moving through B.C at
times. Breezy winds and showers, mainly near the Cascade crest and
along the higher terrain of the northern and Panhandle mountains
will be possible with each of the aforementioned waves. Hard to
pinpoint the exact timing right now. Temperatures will be near or
on the warm side of normal through the weekend. Tobin 


&&

.AVIATION...
06Z TAFS: A building upper level ridge aloft and weak high
pressure at the surface will promote VFR conditions at all TAF
sites through at least 06Z Tuesday. There is a low threat of fog
developing from 12-18Z in the northern valleys of NE WA and ID.
Mountain cumulus is expected through the afternoon hours. Clearing
skies is expected from west to east through the late afternoon and
early evening.



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        66  45  75  45  62  39 /   0   0  10  30  20  10 
Coeur d'Alene  67  40  75  41  62  36 /   0   0  10  30  30  10 
Pullman        66  41  73  41  60  37 /   0   0   0  20  30  10 
Lewiston       72  45  82  48  67  42 /   0   0   0  20  20  10 
Colville       70  41  77  46  66  39 /   0   0  10  60  20  20 
Sandpoint      67  36  74  40  61  35 /   0   0  10  30  40  20 
Kellogg        65  39  72  41  59  36 /   0   0   0  30  40  20 
Moses Lake     72  44  78  41  67  39 /   0   0   0  20  10  10 
Wenatchee      74  50  74  44  67  43 /   0   0   0  10  10  10 
Omak           72  43  76  41  67  37 /   0   0  10  10  10  10 

&&

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

$$


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Western Regional Climate Center, wrcc@dri.edu