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Area forecast discussion 
National Weather Service Spokane Washington
1043 PM PDT Monday Mar 30 2015

Synopsis...
a vigorous cold front will arrive early Tuesday. The front will
bring gusty west winds on Tuesday...as well as mainly mountain
showers. Wednesday through the weekend will be seasonably cool
and unsettled with a chance for showers.

&&

Discussion...
update: after evaluating the 18z GFS/NAM model runs and the past
3 hrrr runs...a few edits were made to the overnight forecast. A
slight chance of thunderstorms was added from the Blue Mountains
to the central Panhandle mountains including the Palouse and
Lewiston area. Previous discussions have mentioned this
possibility but confidence has increased a bit more to mention in
the forecast. A slight chance of rain showers was also expanded
westward a bit to include the western Palouse, and Spokane/Coeur
D'Alene area. There is general model agreement that a band of
elevated instability in the 700-500mb layer will develop over
southeast Washington late this evening before tracking northeast
into the central Panhandle mountains overnight. Most unstable cape
values increase to 100-300 j/kg with no convective inhibition
above 700mb. This combined with a Theta-E ridge axis over the
area, and increased forcing may trigger a few thunderstorms. The
hrrr shows this activity could develop and track a bit further
west to include the upper Columbia Basin and Spokane area.
Although thunder is less likely in these areas with the best mid
level instability south and east of these areas. Jw

&&

Aviation...
06z tafs: a cold front will arrive Tuesday morning. Between 06z-
12z, a narrow corridor of elevated instability over NE Oregon, southeast
WA, will increase the threat of scattered high- based showers.
Ceilings should remain VFR, but drop to around 6-9k ft agl. A
couple nocturnal lightning strikes are not out of the question.
Expect to see a dramatic increase in west winds beginning around
15-18z...with gusts as high as 40 mph possible by late morning.
Expect the atmosphere to destabilize Tuesday afternoon as colder
air aloft moves in behind the cold front. The bulk of the showers
given westerly flow are expected near the Cascade crest and Idaho
Panhandle. A few thunderstorms in the afternoon are also
possible...although confidence in this materializing is low at
this time. Jw

&&

Preliminary point temps/pops...
Spokane 42 55 33 51 31 52 / 20 30 20 40 30 30
Coeur D'Alene 40 54 32 49 29 50 / 20 40 20 40 30 30
Pullman 42 53 34 48 32 49 / 20 30 20 50 30 30
Lewiston 47 57 37 53 34 54 / 20 30 20 30 20 30
Colville 38 58 33 54 30 55 / 10 60 20 40 20 30
Sandpoint 37 52 31 49 28 50 / 20 60 30 40 30 40
Kellogg 39 50 32 44 30 46 / 20 80 30 50 40 60
Moses Lake 43 59 35 57 31 59 / 10 10 10 20 10 10
Wenatchee 45 57 39 56 38 58 / 10 10 10 20 0 10
Omak 40 59 32 57 31 58 / 10 20 10 30 10 20

&&

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

$$

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