Area Forecast Discussion
Issued by NWS Spokane, WA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KOTX 010914
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
214 AM PDT TUE SEP 1 2015

.SYNOPSIS...
Today will feature dry and breezy conditions. A weak cold front
brings a reinforcing shot of cooler air Wednesday along with a
chance for showers and gusty winds. A cooler and showery weather
pattern will linger over the region late week and into the
weekend.

&&

.DISCUSSION...

Today through Wednesday...Long-wave trof pattern continues to
influence this portion of the forecast and beyond.  Shortwaves
nested towards the center and the edges rotate around and brush
the forecast area with forcing and moisture maximizing along
the Cascade Crest and near the Northern Canadian border today
and tonight. A somewhat stronger frontal feature sweeps through
Wednesday with enough intensity and speed to place higher pops
in place for those same locations noted earlier and in addition
include a good portion of the North Idaho Panhandle. Southwest
winds should prevail with such a scenario allowing breezy
conditions here and there today with slightly more gusts
Wednesday. Forecast temps with such a trof in place should remain
on the cool side of normal for this time of year. /Pelatti

Thursday through Saturday...Model agreement is decent and
consistent over previous runs during this period. Wednesday`s cold
front will be the surface harbinger of a cool upper level closed
low descending into the forecast area from Canada. In addition to
continued unseasonably cool conditions...a showery transition
season type pattern will envelop the region as the cool air in
the center of this low produces instability each afternoon through
Friday. Thursday the shower activity will likely be concentrated
over the mountains around the basin as the upper low begins to
move in...while on Friday just about any location in the forecast
area will be subject to a hit-and-miss shower or brief
thunderstorm with the cold pocket square over the region. Both the
GFS and EC models develop a wrap around moisture band by early
Saturday over southeastern Washington and the Idaho Panhandle.

Winds during this period will be relatively light over most of
the area but the Okanogan Valley and eventually the Purcell Trench
will begin to funnel some drier Canadian continental air into the
basin...first noticeable on Friday in the Okanogan and Friday
night/saturday down the Purcell Trench. These terrain
constrictions could produce breezy northerly winds Friday and
Saturday.

Sunday and Monday...Models diverge during this period with the
ECMWF much slower to eject the upper low to the east...implying a
continued (but improving) unsettled and cool pattern...while the
GFS aggressively moves the low out of the region and implies a
well defined warming and drying trend. Confidence is low...but
compared to previous runs the EC appears to have a more consistent
idea of a slower ejection. Thus the far reaches of the forecast
will maintain some chance of rain in the Idaho Panhandle with a
more anemic warming trend than the GFS would suggest. /Fugazzi



&&

.AVIATION...
06Z TAFS: Areas of light rain will continue across the Cascade
crest and far northern WA tonight but will not impact any TAF
site. Smoke models still bring some smoke from near Pomeroy toward
the KLWS corridor and if this is the case, nocturnal inversions
could result in some reductions of VIS until morning. Confidence
is low due to uncertainty with burning behavior of the NE Oregon
wildfire. KLWS is also vulnerable to smoke from the southeast
where fires are burning in central ID. Some smoke is expected to
settle into the valleys of northern WA and northern panhandle of
Idaho. Breezy early evening winds will diminish overnight but will
become breezy again Tuesday afternoon. /EK



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        74  52  68  44  66  45 /  10  20  20  10  10  10
Coeur d`Alene  74  52  67  43  65  41 /  10  20  20  10  20  20
Pullman        76  50  68  42  66  40 /   0  20  30  10  10  10
Lewiston       83  58  73  49  71  48 /   0  10  20  20  20  10
Colville       74  50  70  40  68  40 /  10  20  30  10  20  30
Sandpoint      72  48  66  40  65  37 /  10  20  20  10  20  20
Kellogg        73  49  65  41  63  40 /   0  20  40  20  20  20
Moses Lake     77  53  73  47  71  45 /  10  10  10  10  10  10
Wenatchee      75  56  71  50  69  52 /  10  10  10  10  10  20
Omak           75  49  72  43  68  45 /  20  20  20  10  30  30

&&

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

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.