Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 030549

Area Forecast Discussion
National Weather Service Spokane WA
1049 PM 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.


.DISCUSSION... Tonight though Saturday evening: Hot and dry
conditions will continue across the Inland Northwest courtesy of a
ridge of high pressure. As of 2PM...several locations across the
lower Columbia Basin were already recording triple digit
temperatures and the air mass is only going to warm into Friday.
The ridge however will begin to weaken by the evening and this
will allow a local increase in winds and elevate the threat for
wildfire spread. Our first concern will be near the Cascade Gaps
starting around late afternoon and evening on Friday. Confidence
is higher that winds will materialized in Ellensburg and red flag
warnings have been hoisted. Confidence is lower for the Wenatchee
River Valley where model consensus is only indicating winds 8-14
mph between 5-8PM. There is an isolated run of the higher res NMM
that would support a low-end red flag but given the lack of
support from MOS, will hold off on upgrade at this point and let
the next 2 shifts examine the incoming 00z model guidance.

As the ridge deflates Saturday, we will look for increasing northerly
pressure gradients and eventually a dry cold front passage Saturday
afternoon and evening. Temperatures will remain warm but do come
down some from Friday. A bigger impact will be increasing
northerly winds which will be squeezing through the Okanogan
Valley and spilling into the Western Columbia Basin. We should see
gusty winds in the Okanogan Highlands as well and red flag
warnings have been issued to address the concern for low humidity
and winds. We will also see an increase of north winds in Stevens
and Pend Oreille Counties as well as the West Plains toward the
Hwy 2 corridor. At this time, these winds look to be a bit weaker
in a sustained standpoint but will have the potential to produce
gusts 20-30 mph, especially along exposed ridge-tops.

Temperatures during the 4th of July festivities will be quite comfortable
but winds will raise concern for wildfire starts. Even if humidities
climb out of critical thresholds by dark. Please be advised that
fuels around the region are generally as dry as they are by late
August and this will elevate the risk for wildfire ignitions
around fireworks whether there is a red flag warning or not. /sb

Saturday evening through Thursday...Northerly flow between the
edge of a ridge with axis over the Gulf of Alaska with departing
trof in Northern Montana keeps some breezy conditions going
through the evening in some locations. This northerly flow has a
nice influence on temperatures for Sunday as they are about 10
degrees cooler in comparison to Friday`s high temps, yet they are
still above normal for this time of year given this ridge. The
ridge axis remains off the coast for the remainder of the forecast
which means there is potential for more weather disturbances to
drop down along the east edge of the ridge in a northwest to
southeast trajectory through Wednesday. The GFS and the ECMWF
suggest the best potential for such a scenario in the Tuesday and
Wednesday time intervals and limits the measurable precipitation
generated in the form of showers and thunderstorms to the extreme
Northeast Portion of Washington and the Northeast edges of the
North Idaho Panhandle. By Thursday models suggest the ridge is
undercut by westerly flow and leaves Eastern Washington and
Northern Idaho somewhat of a split flow with the jet stream and
active weather associated with it well to the north and a closed
low over Central California that has nuisance mesoscale
disturbances rotating around it well to our south. /Pelatti


06Z TAFS: A dry and stable airmass will remain over the aviation
area allowing for VFR conditions at all TAF sites through 06Z
Sat. NW winds will increase in the late afternoon across the KEAT
taf site.


Spokane        69 100  67  96  64  89 /   0   0   0   0   0   0
Coeur d`Alene  63  97  63  94  61  85 /   0   0   0   0   0   0
Pullman        58  97  58  93  56  90 /   0   0   0   0   0   0
Lewiston       70 105  70 101  68  97 /   0   0   0   0   0   0
Colville       63 102  62  98  59  93 /   0   0   0   0   0   0
Sandpoint      59  96  55  93  54  85 /   0   0   0  10  10   0
Kellogg        60  97  61  92  58  86 /   0   0   0   0   0  10
Moses Lake     69 107  67 101  69  96 /   0   0   0   0   0   0
Wenatchee      75 105  72 101  72  98 /   0   0   0   0   0   0
Omak           70 104  68  98  64  96 /   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-Okanogan Valley-Upper
     Columbia Basin-Washington Palouse-Wenatchee Area.

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

     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).

     Red Flag Warning from 3 PM to 9 PM PDT Friday for East
     Washington South Central Cascade Valleys (Zone 676).


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