Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 031734
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1034 AM PDT FRI JUL 3 2015

.SYNOPSIS....
Hot and dry weather will be featured into the Independence Day
weekend. Today will be the warmest day, with many valley sites
topping the century mark. Winds will increase as systems move
across the upper level ridge. Today and Saturday winds will be
increasing as a front tries to sag in from Canada, eventually
forcing winds more from the north. It is still looking dry and
warm into the beginning of next week.


&&

.DISCUSSION...

...HOT..DRY AND BREEZY CONDITIONS CONTINUE THROUGH INDEPENDENCE
DAY...

Today through Saturday...The ridge of high pressure will start to
be suppressed by an upper trough that will descend out of British
Columbia for the holiday weekend. Expect one more day of
widespread triple digit temperatures today. We may see some thin
high clouds over the northern zones but no precipitation for the
weekend. The main weather concern will be breezy to windy
conditions that will combine with very dry conditions to elevate
fire weather concerns. The first area of concern is the Cascade
gap valleys where northwest winds will be funneled down the
valleys. The Fire Weather Watch for fire wx zone WAZ677, which
includes the Wenatchee Valley, has been upgraded to a Red Flag
Warning. High resolution models show the winds will be right at or
just below warning criteria during this afternoon when relative
humidity will be at its lowest. We are acting on the side of
caution since fuels are much drier that usual for this time of
year and despite the widespread banning of pyrotechnics, humans
love their fireworks. The Red Flag Warning remains in effect for
WAZ676, including the Kittitas and Yakima Valleys.

The next concern will shift to the Okanogan Valley, Waterville
Plateau and western Columbia Basin on Saturday. Winds will shift
to northerly in response to an cold front approaching from the
north. The surface pressure gradient will tighten Saturday with
sustained winds increasing to 15 to 25 mph by early Saturday
morning. Winds will continue to increase through the day with
gusts of 30 to 40 mph possible. Models have been backing off a bit
on the strength of the wind speeds but even the lower range will
easily reach critical fire weather criteria when combined with
very low RH during the afternoon and evening hours. Any fire
starts on Friday will be problematic in these windy conditions for
Saturday. The elevated winds will keep overnight temperatures in
the upper 60s to low 70s for the exposed areas while the more
sheltered areas will cool off a bit more. Daytime temperatures for
Independence day will be mainly in the 90s, a little more
comfortable but still well above normal. /Kelch

Saturday night through Friday...In the big picture an interesting
pattern is setting up through this portion of the forecast
period. A rex block (high pressure in the Gulf of Alaska and low
pressure off the CA coast) will keep the region in a northwest to
northerly flow through the middle of the week. A pair of
disturbances will drop through the northeast zones and result in
slightly cooler temperatures...breezy/gusty winds and a chance for
showers and embedded thunderstorms at times.

Saturday night and Sunday the first wave will drop down out of
B.C. Winds will increase through the day on Saturday and will
continue down the Okanogan valley and the Kettle river
valley...with the north winds gradually getting into the Purcell
trench Saturday night and Sunday. The atmosphere will remain very
dry with poor overnight recoveries. A Red Flag warning is in place
through Saturday evening and that looks like a very good call
still. The models are hinting at some moisture associated with
this front just clipping the north Idaho Panhandle. Typically
fronts that originate in the northern Canadian plains are pretty
dry and the decision was made to keep conditions dry. Temperatures
will drop 3-5 degrees on Sunday but will still remain well above
seasonal averages.

Weak high pressure Sunday into Monday will give way to another
wave Monday night and Tuesday taking a track very close to the
one on Saturday. Model guidance has been very similar the past
several runs showing a decent surge of mid level moisture with the
front. As such pops were bumped up a bit for the northeast
Washington mountains and the Idaho Panhandle. Instability
parameters are such that embedded thunderstorms will be possible
late in the day and early evening. The models diverge Tuesday
night and Wednesday, with one model hanging onto the shortwave and
others keeping the flow progressive. Pops were kept along the
ID/MT border into Wednesday but confidence is low that anything
other than some fair weather cumulus will develop. Temperatures
will remain in the 80s and 90s.

Thursday and Friday...Model consistency really begins to fail
Thursday and Friday. The consensus will be for weak high pressure
to build back into the region both days for a slight warm up and
very dry conditions. Stay tuned. Tobin

&&

.AVIATION...
18Z TAFS: Dry airmass will allow for VFR conditions at all TAF
sites. Winds will increase in the late afternoon across the EAT.
Elevated smoke layers from area wildfires will appear as thin mid
level clouds but surface visibility will not be affected. /J. Cote`



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane       100  68  96  65  89  64 /   0   0   0   0   0   0
Coeur d`Alene  97  63  94  61  86  59 /   0   0   0   0   0   0
Pullman        97  58  93  57  91  55 /   0   0   0   0   0   0
Lewiston      104  70 101  69  98  68 /   0   0   0   0   0   0
Colville      102  64  98  60  93  58 /   0   0   0   0   0   0
Sandpoint      96  55  93  54  85  51 /   0   0  10  10   0   0
Kellogg        97  62  92  59  85  56 /   0   0   0   0  10   0
Moses Lake    106  68 102  70  97  66 /   0   0   0   0   0   0
Wenatchee     105  74 101  72  98  72 /   0   0   0   0   0   0
Omak          104  69  98  63  96  64 /   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 from 3 PM this afternoon to 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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