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Area forecast discussion 
National Weather Service Spokane Washington
228 PM PDT Friday 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 northwest 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 British Columbia 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 northwest. This comes with a marginal
increase in layer moisture and instability, especially toward the
Idaho/Montana 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 Idaho/Montana
border Saturday night. Other chances continue across the central
and lower Idaho 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 Idaho Panhandle mountains and
far northeast Washington mountains. Others bring the threat over a broader
portion of the inland northwest. 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 California coast. That California 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 Washington
and the lower Panhandle and move up along the Idaho/Montana border, with a
few solutions wrapping some threat back across the northern Washington
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...
Idaho...heat advisory until 9 PM PDT this evening for Lewis and southern
Nez Perce counties-Lewiston area.

Washington...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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