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Area forecast discussion 
National Weather Service Spokane Washington
440 am PDT Tuesday Sep 30 2014

Synopsis...
cooler temperatures will arrive today courtesy of a passing cold
front. The front will also deliver breezy winds and scattered
showers. Dry weather will return on Wednesday. Look for a warming
trend and a continuation of mainly dry conditions Thursday into
the weekend.

&&

Discussion...

Today and tonight...cool, wet, and somewhat unstable trof of low
pressure continues to make slow progress through eastern
Washington and northern Idaho with an eventual exit into Montana
by early Wednesday. Therefore until its exit some mention of
showers that translates east and decreases in coverage into
tonight coupled with the possibility of an afternoon thunderstorm
or two up north remain in the forecast. Forecast temperatures
remain quite close to normal given the cool trof and some
gustiness in winds, primarily from the southwest and west,
remains. /Pelatti

Wednesday through Friday...this will generally be a dry weather
period as the upper level jet retreats to our north and east. This
transition will result from an amplifying ridge off the coast and
vigorous trough passing through the northern half of British Columbia. The
passage of the trough will likely deliver some showers near the British Columbia
border and the immediate Cascade crest however model sounding in
these areas suggest the moisture could be too shallow for anything
of significance.

For Thursday and Friday we will see a true sign of the changing
seasons...the approach of a warm front and a well-defined
atmospheric river. Model solutions are in good agreement that the
warm front will move into the northern Cascades late Thursday and
across the northern half of Washington and the Idaho Panhandle
through Friday. Suspect the main impact of the frontal boundary
will be an increase in clouds and gradually warming temperatures.
Precipitation chances are looking less certain as the upper level
jet is expected to remain over British Columbia with the atmospheric river
remaining west and north of the inland northwest through at least
Friday afternoon. High temperatures will rebound from the 60s
today and into the upper 60s and 70s by Friday. Fx

Friday night through Monday night: pattern looks to remain pretty
consistent through the extended as we sit in westerly to
northwesterly flow throughout. Models have the jet stream
remaining to our north which would put the inland northwest on the
warmer, more stable and less active southerly side. This in turn
limits the chances for precipitation late this week and into early
next with the only notable chances near the Cascade crests and the
higher terrain northern Washington and the Idaho Panhandle. With an
atmospheric river directed at the southern British Columbia coast for the early
portions of the period, moisture on the southern periphery will
influence our conditions a bit. The main impact we will see is
increased clouds throughout the region along with the mentioned
low end chance for mountain precipitation. Breezy winds is another
feature showing up in the extended with the Cascade gaps and high
ridgetops bearing the brunt of it. Currently this by no means
looks to be a high end event, just more of a seasonal fall wind
pattern. Finally temperatures continue the above normal trend as
the central Pacific origins of our airmass pushes US 5-10 degrees
above normal with widespread 70s expected for daytime highs.
Overnight lows remain mild as increased cloud cover reduces the
amount of radiative cooling. Overall conditions for the extended
forecast look quite pleasant as we push further into the fall
season. /Fliehman

&&

Aviation...
12z tafs: a weak cold front moving through eastern Washington and north
Idaho will bring moisture, instability and lift allowing for
potential for showers and possibly an afternoon thunderstorm.
Best chance for precipitation will be those areas favorable to
westerly upslope flow. VFR conditions should prevail at taf
sites.




&&

Preliminary point temps/pops...
Spokane 63 40 61 39 64 45 / 30 10 0 0 0 10
Coeur D'Alene 62 40 62 40 63 43 / 50 20 0 0 0 10
Pullman 62 38 62 37 65 42 / 20 10 0 0 0 0
Lewiston 68 45 68 45 71 47 / 10 10 0 0 0 0
Colville 67 36 66 38 67 43 / 30 10 0 0 0 10
Sandpoint 60 39 60 36 61 39 / 60 30 0 10 0 10
Kellogg 56 37 56 40 59 43 / 60 30 10 10 0 10
Moses Lake 71 40 69 41 68 45 / 10 0 0 0 0 0
Wenatchee 69 46 68 45 69 49 / 0 0 0 0 0 10
Omak 69 38 66 39 66 46 / 10 10 0 0 0 10

&&

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

$$

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