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Area forecast discussion
National Weather Service Spokane Washington
430 am PDT Sat Sep 23 2017

Synopsis...
a drying and warming trend is expected for the inland northwest
through next week. High temperatures through the weekend will
still be below normal with highs mainly in the 60s with the
warmest spots near 70. By the end of next week, look for
temperatures to surge well into the 70s.

&&

Discussion...

Today through Sunday night: narrowing, elongating, and splitting
trof continues a slow exit to the east as it gets replaced with
northerly flow on the eastern edge of a positively tilted trof that
is slowly moving into the area. Nuisance complications of note with
this scenario necessitate low minor pops in portions of north Idaho
as minor disturbances rotating counterclockwise around the outer
edges of a mesoscale low pressure circulation centered in southern
Alberta have potential for producing light showers there. By tonight
the northerly flow of the positively tilted ridge has much more
influence with the earlier mentioned low pressure circulation moved
much further east and as such a dry forecast coupled with a gradual
warming trend remains in place as the ridge shows some slight
amplification but the temperatures will still be cooler than what
would be considered normal for this time of year. /Pelatti

Monday through next weekend: the big story through this period will be
dry weather and warm temperatures courtesy of a a strong upper-level
ridge. The ridge will be slow to amplify Monday and Monday night
as one last shortwave passes through bringing an abundance of
clouds and chance for light mountain showers. Despite a rich fetch
of moisture tied into the system, the forcing will be on the weak
side and most locations will receive less than a tenth of an
inch. There is decent model agreement that the northern mountains
will stand the best shot at receiving a few hundredths of rainfall
while the basin receives little to nothing.

The shortwave will depart to the east Monday night then high
pressure will Blossom over the northwestern US. The dry and stable
air mass will be in place through at least Friday promoting
afternoon highs in the 70s and 80s, roughly 6-10 degrees above
normal. The next disturbance will run into the ridge over the
weekend bringing a slight chance for precipitation and cooler
temperatures. There remains some uncertainty regarding
precipitation chances this far out and forecast continues to favor
a stronger ridge, little to no rain, in line with the
European model (ecmwf)/Canadian vs GFS. Winds are likely to be on the breezy side
as the air mass cools 4 to 5 celsius from Friday to Sunday. For
the first week of autumn, the weather looks to start off rather
quiet with no hazardous weather anticipated. /Sb

&&

Aviation...
12z tafs: middle level clouds with cigs above 6 kft agl will
linger over the region. There is a still potential that this
moisture will result in light rain across the northern Panhandle
late tonight into Saturday morning. Isolated afternoon showers
will then be possible over extreme eastern Washington and the Idaho Panhandle
for Saturday afternoon. Mountain obscurations will be possible
over the Idaho Panhandle.



&&

Preliminary point temps/pops...
Spokane 62 42 64 46 66 45 / 10 10 0 10 10 10
Coeur D'Alene 60 38 64 42 66 44 / 10 10 10 10 10 10
Pullman 59 39 63 42 66 44 / 10 10 0 0 10 10
Lewiston 66 44 68 48 71 50 / 10 0 0 0 10 10
Colville 65 38 68 43 70 44 / 10 10 10 10 10 10
Sandpoint 59 35 63 41 65 43 / 30 10 10 10 10 20
Kellogg 55 35 61 41 63 43 / 20 10 10 10 10 20
Moses Lake 69 43 70 45 73 46 / 0 0 0 0 10 10
Wenatchee 70 48 71 50 73 51 / 0 0 10 10 10 10
Omak 69 42 71 44 73 46 / 10 0 10 10 10 10

&&

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

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