Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 251730
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1030 AM PDT Mon Jul 25 2016

.SYNOPSIS...
A warm, summery and mostly dry summer pattern will continue
through the work week. However, there will be a chance for
thunderstorms near the Canadian border Monday through Wednesday.
High temperatures in the 90s will be common for nearly all towns
this week with a cool down expected next Sunday. Gusty winds will
accompany this cool down...especially across the Columbia Basin.


&&

.DISCUSSION...
Today and Tuesday: A weak upper level wave will move in over the
region on Tuesday off of the eastern Pacific. The best
instability for today will be over the east slopes of the Cascades
where dew point temps will be in the lower 50s. Surface based
CAPEs are expected to range between 500-1500 J/kg; but, models are
also indicating a healthy cap in place that will act as a lid on
the convection. The approaching disturbance will begin to move in
to western WA in the evening. Dynamics out ahead of this wave will
be very weak and may not be enough to break the cap that is
expected to be in place. The NAM shows a weaker CAP with a CIN of
near 20 J/kg over the higher terrain just east of the crest, with
the best potential for thunderstorms over the Pasayten Wilderness
area of the Cascades near the Canadian border. Chances will be
less the further south down to about Lake Chelan. The steering
flow will be weak and P-wats will be up near an inch, which will
result in Thunderstorms capable of producing heavy rainfall. The
good news is that the chances for a thunderstorm to develop near a
recent burn scar looks low.

There is a small chance for nocturnal convection to continue into
Monday night, but confidence is low due to lack of forcing
available. Models then show a higher chance for convection across
the northern mountains on Tuesday. Best chances will reside in
areas closer to the Canadian border. The ECMWF solution has been
consistent with convection across much of the region, but this
model is an outlier. Convection will be possible near recent burn
scars above the Methow Valley, Okanogan Vly and in the Okanogan
Highlands. Thunderstorms will continue to be wet and slow moving,
but there is a question with how widespread thunderstorms will
be. I am leaning more toward the GFS and NAM solutions that tend
to keep convection closer to the Canadian border mostly north of
the burn scars.

Temperatures will be warm today and Tuesday with highs in the 90s
for most locations. /SVH

Tue Nt through Mon Nt: Following a very weak short-wave passage
Wed that will produce isolated Tue Nt showers along the BC border,
expect a warming trend. The warmest weather should peak Fri with
nearly all of Ern Wa and N Idaho well into the 90s under a pronounced
thermal ridge surging NE ahead of an approaching broad offshore
trough. This trough will help to lower temps to normal values late
weekend into next week, but this transition to cooler weather
will likely accompany gusty winds across the Columbia Basin as
well. We left the fcst dry with this trough passage given the timing
uncertainties between model guidance as well as being under an
extremely wide dry slot despite the model timing disagreements.bz

&&

.AVIATION...
18Z TAFS: High pressure will continue mostly sunny skies and weak
winds today. The exception will be at KEAT where gusty northwest
gap winds will develop by this evening. Some high cirrus will be
found to the north along with a few afternoon cumulus. There is
good agreement that isolated convection will develop this
afternoon in the northern Cascades late this afternoon and early
evening. Some this convection may drift along the Canadian border
overnight, but stay north of the TAF sites. /rfox.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        92  64  90  63  90  63 /   0   0  10  10   0   0
Coeur d`Alene  90  60  90  59  88  59 /   0   0  10  10   0   0
Pullman        90  55  88  54  88  53 /   0   0   0   0   0   0
Lewiston       98  66  96  65  95  66 /   0   0   0   0   0   0
Colville       93  57  90  56  90  57 /   0  20  30  20  10  10
Sandpoint      87  53  86  54  85  55 /   0   0  20  20  10  10
Kellogg        88  56  87  54  85  54 /   0   0  10  10   0   0
Moses Lake     95  64  94  61  93  62 /   0   0   0   0   0   0
Wenatchee      94  68  91  66  92  66 /   0  10   0   0   0   0
Omak           94  66  93  65  93  65 /   0  20  10  10  10  10

&&

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

$$



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