Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 032128
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
228 PM PDT FRI JUL 3 2015

.SYNOPSIS....
Hot and dry weather will be featured into the Independence Day
weekend. Winds will increase as systems move across the upper
level ridge. This evening and Saturday winds will be increasing
as a front tries to sag in from Canada, eventually forcing winds
more from the north. Breezy conditions continue on Sunday. It is
still looking dry and warm into the beginning of next week.

&&

.DISCUSSION...
Tonight through Friday: The Inland NW will be in a west to
northwest flow much of this period and the occasional shortwave
passes, carrying minor shower chances and occasionally breezy
conditions. Yet as a whole the pattern remains dry with above
normal temperatures.

Between tonight and Saturday some minor ripples in the
west-northwest flow bring a few middle to high clouds, but
otherwise dry conditions. The first substantial shortwave
approaches from BC into Saturday and the thermal low over the
Columbia Basin migrates southeastward. This will increase the
north-south gradient and increase north to northwesterly winds
down the Okanogan between tonight and Saturday. Speeds in the 15
to 25 mph range will be possible here by Saturday morning, with
gusts in the 35 to 40 mph range possible by afternoon. Meanwhile
southwest winds will continue across the lower Columbia Basin into
the Palouse through the Idaho Panhandle.

Between Saturday night and Sunday night the first substantial
shortwave drops across the Inland NW. This comes with a marginal
increase in layer moisture and instability, especially toward the
ID/MT border and perhaps near the Cascade crest. Look for some
band of clouds to drop in Saturday night into Sunday morning,
before some drier air slips in from the north later Sunday. A
slight threat of showers and thunderstorms skim by the ID/MT
border Saturday night. Other chances continue across the central
and lower ID Panhandle mountains into the Camas Prairie in the
developing northwest flow for Sunday afternoon and early evening.
Otherwise the region will remain dry, with clearing into Monday.

The more notable and continuing feature will be winds. Just in
time to heighten the concern around the Fourth of July evening,
speeds will be or rise into in the breezy category. Directions
turn north-northwest over much of the region Saturday night,
before they gradually shift north-northeast into Sunday. We will
continue to see some channeling and higher winds down the Okanogan
Valley and out through the Purcell Trench. Speeds then begin to
subside Sunday afternoon and especially Sunday night.

Between Monday night and Tuesday night the second substantial
shortwave drops through. This system carries more moisture and
instability and overall has a better threat of showers and
thunderstorms. However there remains a fair amount of model
disagreement over just how much of the threat it will bring. Some
models hold the main chances across the ID Panhandle mountains and
far northeast WA mountains. Others bring the threat over a broader
portion of the Inland NW. For now on Monday night clouds increase
some and the main shower threat comes into the Okanogan Highlands
through the northern Panhandle. By Tuesday expanding surface-based
instability and lift with the incoming wave will increase the
threat of showers and thunderstorms. Still, the overall best
chances will remain across the mountains. Breezy conditions also
accompany this shortwave but compared to the weekend winds they
don`t look at strong.

From Wednesday to Friday model agreement falters. Initially the
region will remain in north or westerly flow, with a ridge to the
west and low pressure off the central CA coast. That CA low
migrates inland through the end of the week and some instability
wraps around the mountains, while the deeper Columbia Basin
remains relatively stable. Where models disagree is over whether
some energy coming around that incoming low drifts north into our
region to bring at least an isolated shower and thunderstorm
threat. Through Thursday most models keep the threat south of the
region of just into our Blues/Camas Prairie. The GFS brings
chances into the Cascades by Thursday, but for now this seems an
outlier. By next Friday better chances come to the southeast WA
and the lower Panhandle and move up along the ID/MT border, with a
few solutions wrapping some threat back across the northern WA
mountains. /J. Cote`

&&

.AVIATION...
00Z TAFS: A dry airmass will allow for VFR conditions at all TAF
sites. Winds will increase in the late afternoon across EAT and
remain occasionally breezy through Saturday. Elevated smoke
layers from area wildfires will appear as thin mid level clouds
but surface visibility will not be affected. /J. Cote`


&&

.FIRE WEATHER...
There are elevated risk for rapidly spreading wildfires through
the weekend as winds increase. Winds increase locally near the
Cascades Friday afternoon then across most of Central and Eastern
Washington on Saturday. Gusty winds will continue well into Sunday
with gusty northeast winds spreading into the North Idaho
Panhandle Saturday night and Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        67  96  66  87  62  92 /   0   0  10   0   0   0
Coeur d`Alene  62  94  62  84  58  90 /   0   0  10  10   0   0
Pullman        58  94  57  89  53  91 /   0   0   0  10   0   0
Lewiston       69 102  70  98  66  98 /   0   0   0  10  10   0
Colville       64  98  60  92  58  95 /   0   0  10   0   0  10
Sandpoint      55  93  54  83  50  89 /   0   0  10  10   0   0
Kellogg        62  93  59  83  54  89 /   0   0  10  10   0   0
Moses Lake     68 102  70  97  65  99 /   0   0   0   0   0   0
Wenatchee      73 102  72  98  71 100 /   0   0   0   0   0   0
Omak           67  98  63  96  63  98 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory until 9 PM PDT this evening for Lewis and Southern
     Nez Perce Counties-Lewiston Area.

WA...Heat Advisory until 9 PM PDT this evening for Lower Garfield and
     Asotin Counties-Moses Lake Area-Okanogan Valley-Upper
     Columbia Basin-Washington Palouse-Wenatchee Area.

     Red Flag Warning until 9 PM PDT this evening for East Washington
     Central Cascade Valleys (Zone 677)-East Washington South
     Central Cascade Valleys (Zone 676).

     Red Flag Warning from Noon to 10 PM PDT Saturday for East
     Washington Northern Columbia Basin (Zone 673)-East
     Washington Okanogan Highlands (Zone 687)-East Washington
     Okanogan/Methow Valleys (Zone 684).

&&

$$


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