Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 250056
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
435 PM PDT TUE MAY 24 2016

.SYNOPSIS...

Following showers and isolated thunderstorm this evening, expect a
warming and drying trend. Wednesday will be the warmest day of the
week, with temperatures in the 70s and the potential for
thunderstorms in Idaho and northeast Washington. The Memorial Day
weekend will likely be chilly and showery with the arrival of
another slow moving low. More unsettled spring time weather is
likely through early next week.

&&

.DISCUSSION...

Tonight through Wed Nt: With the upper trough (currently
stretching from NE Oregon to the Idaho Panhandle) translating
slowly E the next 24 hours...we`ll be transitioning to a drier,
slightly more stable air mass with upper ridging replacing the
trough. Sfc heating combined with steep mid-level lapse rates aloft
in the vcnty of this trough is at least partly responsible for
the showers and isolated thunder currently moving south roughly
north of a line from Kellogg to Spokane and Omak. Uncapped SBCAPE
no more than about 500 j/kg in an environment of only modest deep
layer shear should continue to generate short-lived small clusters
of thunder (and locally heavy downpours) over preferred initiation
points such as mtn ridges and along lines of moisture convergence
from thunder outflow. Our only concern is very localized heavy
downpours that may produce brief ponding... or minor flooding in
and close to burn scars across NE Wa this evening. Shallow
instability Wed will lead to isolated showers in nearly the same
zones as today. bz

Thursday through Tuesday: The region will be stuck in a generally
unsettled and cool spring time pattern through the next week. The
latest major model guidance is similar and reasonably consistent
over previous runs. A marginally dry day on Thursday...but still
with a residual threat of mountain showers will deteriorate back
into a scattered shower and thunderstorm pattern Thursday night
and Friday as another closed low directly transits through the
region. Friday looks like the most active day with the closed low
and associated destabilizing cold pool aloft laying directly over
the forecast area. The upper low will exit the region to the
northeast on Saturday...but carry a continuing threat of residual
showers in it`s wake mainly over the Idaho Panhandle and northeast
mountains. Sunday...like Thursday...may be a break period with
only a small threat of mountain showers but the next in a
seemingly never ending wave of closed lows will descend into the
region on or about Monday or Tuesday...timing is uncertain and
some model differences develop by this time.

Throughout this extended forecast period confidence is high that
temperatures will remain below normal during the daytime periods
and around normal for overnight lows with no freezing temperatures
expected outside of the mountains. There will be no easily
identifiable or organized storm systems suggestive of any downright
wet periods of significant and sustained rain such as occurred
over the last few days...but hit-and-miss showers will be common
along with mainly garden variety thunderstorms during the
afternoons and evening hours as the closed lows approach and
transit the region. A sustained westerly pressure gradient will
also produce breezy and occasionally gusty conditions over the
basin and especially near the Cascade gaps. /Fugazzi

&&

.AVIATION...
00Z TAFS: One disturbance slips south early this evening and a
secondary skirts by the ID Panhandle late this evening/early
overnight. Instability will wane with the sunset. Thus the threat
of isolated showers around the TAF sites will wane after 02-03Z.
The secondary could keep some shower threat alive through the
early overnight near COE but the risk is small. Otherwise expect
VFR conditions. A slight threat of showers redevelops around the
eastern TAF sites after 18-21Z Wednesday. Increased mixing and a
cold front approaching the West coast will also allow for some
marginally breezy conditions in the afternoon. /J. Cote`

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        49  70  48  67  44  60 /  40  20  10  10  20  50
Coeur d`Alene  47  68  48  66  44  59 /  60  30  20  10  20  50
Pullman        46  66  45  64  43  58 /  30  20  10  10  10  30
Lewiston       52  73  51  70  48  65 /  30  20  10  10  10  20
Colville       46  73  46  70  45  62 /  50  40  20  20  40  80
Sandpoint      44  67  47  64  43  58 /  50  40  20  20  30  50
Kellogg        43  63  44  59  40  55 /  60  40  20  20  20  50
Moses Lake     49  77  49  74  47  68 /  10  10   0  10  20  30
Wenatchee      53  76  52  72  49  65 /  10   0   0  10  20  30
Omak           50  76  49  74  47  65 /  20  10  10  20  30  60

&&

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

$$



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