Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 021727

Area Forecast Discussion
National Weather Service Spokane WA
1027 AM PDT THU JUL 2 2015

Hot and dry weather will be featured into the Independence Day
weekend. Hottest days will likely be today and Friday with many
valley sites topping the century mark. Breezes will be kicking up
as weather systems move across the strong upper level ridge.
Friday and Saturday winds are potentially looking more substantial
as a cool front tries to sag in from Canada eventually forcing
winds more from the north. It is still looking dry and warm even
into the beginning of next week.




Today through Friday...Hot and dry weather will prevail across the
Inland Northwest as a ridge of high pressure remains the dominant
feature affecting the region. Temperatures will be in the mid 90s to
105 for the valleys with overnight lows in the 60s, very close to
record territory for several locations. A weak shortwave trough will
flatten the ridge slightly today as it clips the northern tier of
counties. This will result in northerly winds channeled down the
Okanogan Valley but wind speeds will generally be 10 kts or less and
not expected to elevate fire weather concerns today. There is a
slight chance of thunderstorms across extreme northern Idaho this
afternoon/evening but most models keep showers just north of the
border. The ridge will bounce right back to bring triple digit
temperatures to much of the forecast area Friday. Heat Advisories
have been issued for the lower valleys for both today and Friday.

The main weather concern will be Cascade gap winds that will begin
to affect the central Cascade valleys Friday afternoon as relative
humidity drops below 15 percent. Greatest confidence in reaching
critical fire weather conditions of wind and low RH will be in the
Kittitas Valley with lower confidence for the Yakima and Wenatchee
valleys where winds will be borderline. A Fire Weather Watch
continues for these fire districts for Friday afternoon. Considering
that numerous small brush/grass fires and a few larger fires have
ignited over the past week, even marginal conditions are of great
concern to the fire community. /Kelch

Saturday through Thursday...It looks like there will finally be
a pattern change for the Pac NW this weekend and into the middle
of next week. The strong ridge will retrograde out into the
eastern Pacific and set up a blocking pattern across the
northwest. In addition a deep upper level low will build back to
the west and allow a fairly active cold front to clip the
northeast zones Tuesday and Wednesday.

Saturday will be a breezy/gusty day with slightly cooler
temperatures but continued dry conditions. This will be the result
of a cold front that will brush the northeast zones as an upper
level low moves across the Divide and into the Canadian plains.
The surface pressure gradient will increase from north to south as
high as 6 mb by Saturday afternoon. This will increase the winds
down the Okanogan valley Saturday morning to around 20 to 30 mph
with much higher gusts. These winds will spill out onto the
Waterville Plateau and the upper Columbia Basin. Combined with
very low relative humidity the stage will be set for hazardous
fire weather conditions. Fire Weather watches have been hoisted
and will be continued as needed. The front will also take some of
the edge off the oppressive heat with temperatures cooling 3-5

Sunday and Monday...A blocking pattern will develop in the eastern
Pacific with high pressure off the B.C. Coast and low pressure
system off the California coast. This will keep the region in a
dry west to northwest flow with temperatures bouncing around the
high 80s to the mid 90s.

Tuesday through Thursday...a stronger disturbance will eject off
a strong Hudson bay Low and track westward and finally drop south
out of B.C. and Alberta and clip the northeast zones. Disturbances
that develop over the northern Canadian plains are typically not
very wet, however all of the medium range models are similar in
showing a surge of moisture with the front late in the day Tuesday
and lingering through Wednesday. Model guidance is indicating
enough surface based and mid level instability will be present to
kick off afternoon convection both Tuesday and Wednesday east of
the Kettle mountains and south along the ID/MT border. Not totally
convinced that there will be enough moisture to initiate
convection so pops were kept pretty low. Otherwise a dry forecast
is in store for the remainder of the forecast area with
temperatures cooling into the mid 80s to lower 90s, but still
above normal. Tobin


.AVIATION... 18Z TAFS: A dry and stable airmass will remain over
the aviation area allowing for VFR conditions at all TAF sites
through 18Z Friday with the exception of a small chance of
thunderstorms up in North Idaho near the Canadian Border. /Pelatti


Spokane        98  69 100  66  96  64 /   0   0   0   0   0   0
Coeur d`Alene  95  63  97  62  94  60 /   0   0   0   0   0   0
Pullman        95  59  97  58  93  56 /   0   0   0   0   0   0
Lewiston      103  70 105  69 101  68 /   0   0   0   0   0   0
Colville      100  63 102  61  98  58 /   0   0   0   0   0   0
Sandpoint      94  56  96  55  94  54 /   0   0   0   0  10  10
Kellogg        95  60  97  61  92  57 /   0   0   0   0   0   0
Moses Lake    103  69 105  66 100  68 /   0   0   0   0   0   0
Wenatchee     102  73 104  71 100  71 /   0   0   0   0   0   0
Omak          102  67 104  69  98  64 /   0   0   0   0   0   0


ID...Heat Advisory until 9 PM PDT Friday for Lewis and Southern Nez
     Perce Counties-Lewiston Area.

WA...Heat Advisory until 9 PM PDT Friday for Lower Garfield and
     Asotin Counties-Moses Lake Area-Upper Columbia Basin-
     Washington Palouse.

     FIRE Weather Watch from Friday afternoon through Friday evening
     for East Washington Central Cascade Valleys (Zone 677).

     Heat Advisory from 1 PM this afternoon to 9 PM PDT Friday for
     Okanogan Valley-Wenatchee Area.

     FIRE Weather Watch from Saturday morning through Saturday
     evening for East Washington Northern Columbia Basin (Zone
     673)-East Washington Okanogan/Methow Valleys (Zone 684).

     FIRE Weather Watch from Friday afternoon through Saturday
     evening for East Washington South Central Cascade Valleys
     (Zone 676).


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