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Area forecast discussion 
National Weather Service Spokane Washington
217 am PDT sun Mar 29 2015

Synopsis...
the storm track will retreat north into Canada today and Monday
producing mild weather to the inland northwest. A vigorous Spring
storm system will bring another chance for showers and strong
winds to our region on Tuesday. Wind gusts exceeding 40 mph will
be possible Tuesday afternoon and evening. Wednesday through next
weekend looks to be showery with temperatures near normal.



&&

Discussion...

..strong cold front to deliver windy conditions across the inland
northwest Tuesday afternoon...

Today through monday: a flat upper level ridge at 500mb will
reside over the Pacific northwest today into Monday. Vancouver
Island and the southern coast of British Columbia will experience
periods of rain during the next couple of days as a plume of
subtropical moisture is directed into southwestern Canada. Small
chances for light rain will extend as far south as the mountains
of far north central and northeast Washington today and tonight,
but the majority of our forecast area should be dry under bands of
mid and high level clouds. There will be much less wind today and
Monday with the typical afternoon increase in southwest winds,
generally in the 10 to 15 mph range. /Gkoch

Tuesday: a vigorous cold front will seep across the region
Tuesday morning with the upper level trough of lower pressure
moving in for the afternoon. Models are in good agreement with a
deepening surface low scooting across southern British Columbia into southern
Alberta through the day on Tuesday. Models all show the surface
low bottoming out at around 992 mbs along the eastern Divide in
southern Alberta by the afternoon hours. This will set up a
strong surface gradient, which will coincide with a favorable
time of day for mixing potential. The surface gradient looks to be
a little bit stronger compared to this past saturday's wind event
and there were spotty locations with sustained wind speeds of
30-35 mph. This front will have the potential for similar wind
speeds, but on a more widespread basis. This will include anywhere
from the Wenatchee area, across the basin and over into the
exposed areas of the southern to central Idaho Panhandle. Winds up at
850 mbs look to peak at around 35-40 kts, which would translate to
a gust potential somewhere in the range of up to 40-45 mph. There
is a good possibility that a Wind Advisory will be needed for
Tuesday afternoon, but is still a bit early for a highlight at
this time this far out in the forecast period.

A 500 mb cold pool aloft will also result in the atmosphere
destabilizing through the afternoon. Showers will develop out
ahead of the cold front through the morning on Tuesday with more
showers likely developing in the conditionally unstable atmosphere
through the afternoon hours. Best chances for showers are expected
across the eastern half of the forecast area. There will also be a
chance for thunderstorms in the afternoon across the Okanogan
Highlands over into the northern Panhandle.

Tuesday night through sunday: a cold upper level trough of lower
pressure will hang around through Thursday. The cold front on
Tuesday will usher in colder temperatures with temperatures
closer to or slightly below normal. The cold upper level trough
will result in afternoon showers with the potential for some soft
hail or graupel. Shortwave ridging of higher pressure moves in
Thursday night, but another upper level trough of lower pressure
looks to drop down into the region for Friday through the
weekend. This will keep temperatures slightly below normal with
more convective showers expected, especially during the afternoon.
/Svh

&&

Aviation...
06z tafs: the next system will spread an increase in mid and high
clouds across the area overnight into Sunday. Patchy fog or
stratus may develop between 9-15z Sunday for the northern
valleys...but should not impact any of the taf sites. Jw



&&

Preliminary point temps/pops...
Spokane 59 41 63 42 54 33 / 10 10 0 10 60 20
Coeur D'Alene 58 39 64 40 53 32 / 10 10 0 10 70 40
Pullman 60 40 65 41 51 35 / 0 0 0 20 60 20
Lewiston 66 43 70 46 56 37 / 0 0 0 20 50 20
Colville 60 41 65 40 56 31 / 10 10 0 10 70 30
Sandpoint 56 38 59 38 51 33 / 10 10 0 10 80 50
Kellogg 54 39 63 40 47 33 / 10 10 0 30 80 50
Moses Lake 67 40 69 43 59 34 / 10 0 0 0 20 10
Wenatchee 65 44 68 44 58 38 / 10 0 0 10 20 10
Omak 64 39 66 40 60 32 / 10 10 0 10 40 10

&&

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

$$

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