790
FXUS66 KOTX 070439
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
939 PM PDT Sat Jul 6 2024

.SYNOPSIS...
Weather conditions are expected to be hot and dry the next seven
days. Northerly winds decrease into Saturday evening, followed by
lighter winds through Tuesday. Then next increase in winds will
be Wednesday, with continued very dry conditions.

&&

.DISCUSSION...

...SIGNIFICANT HEAT WAVE FOR INLAND NORTHWEST...

Tonight through Wednesday: High pressure will be amplifying over
the West Coast and shifting inland through mid-week. This set-up
will promote hot conditions through this period, peaking around
Tuesday and Wednesday. Highs are forecast to be in the 90s to low
100s Sunday, rising to around 100-110 degrees for most places by
Tuesday into Wednesday. Even in the mountains, all but the higher
peaks will be in the 80s and 90s. Overnight lows will be in the
upper 50s and 60s tonight and Sunday night. However these values
will also see a warming trend dropping to 60s to mid-70s by
Monday night and Tuesday night.

Minor impulses will ride over the top of the ridge through
Tuesday, then in from the west Tuesday night into Wednesday as the
ridge axis shifts toward the Continental Divide. A few afternoon
cumulus clouds are possible around the mountains and a few more
passing clouds pass around Wednesday. However the lack of
significant moisture or instability will keep the area dry,
largely staying north and east of the area. The only area where
models suggest some isolated showers may skirt by is around the
northern Idaho mountains. That dampening of the ridge heading into
Wednesday will come with increased breezy/gusty winds,
particularly near the Cascades into central WA.

Thursday to Saturday, the area shifts to a flatter flow as
additional shortwave make their way onshore. However the lack of
significant moisture over the Inland NW continues to support a
dry forecast. Temperatures will "cool", relatively speaking, with
highs falling to 90s with some lingering low 100s near the deeper
basin and L-C Valley and lows in the upper 50s and 60s. /Solveig

Fire Weather: as for fire weather concerns, afternoon RH
percentages are forecast to range from the single digits in the
deeper basin and lee of the Cascades and teens to lower 20s
heading toward the eastern third of WA and the mountains through
Monday, bottoming out in the single digits and teens throughout
most of the region Tuesday and Wednesday. Overnight RH recoveries
will be fair to poor in most areas, except some of the eastern
valleys early in the period. There is not much improvement after
Wednesday, except around the Cascades crest as the onshore flow
increase. For the most part winds remain light through Tuesday,
then concerns start to rise as we head into Wednesday and
Thursday. The dampening of the ridge and increased onshore flow
leads to an increase in winds. Models are still coming together on
details, but confidence is increasing to show a potential sync up
of winds and low RH around the lee of the Cascades through central
WA, the Upper Columbia Basin. The current forecast indicated winds
near near 15-25 mph and higher gusts. Wednesday looks like the
more impactful day with the breakdown of the ridge. Breezy gap
winds continues into the end of the week too. /Solveig

Smoke/haze: in the short term (through Monday) models are showing
smoke and haze around the Pioneer Wildfire in the Cascades, spreading
over portions of Chelan through Douglas county and perhaps some
spreading into Grant county tonight into early Sunday, abating
some then re-expanding later Sunday into early Monday as far east
as Wilbur in the Upper Columbia Basin. This will likely need
additional fine-tuning and localized smoke is likely around any of
the smaller wildfires near the Cascades. /Solveig


&&

.AVIATION...
06Z TAFS: VFR conditions will prevail, except near the Pioneer
Fire (Lake Chelan area). Smoke aloft (haze) from the fire will
spread into portions of Central WA so retained a FEW200 group for
KEAT/KMWH. Strong high pressure will result in terrain driven
winds of 10 kts or less through Tuesday. JW

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in
VFR conditions. Low confidence for localized visibility
reductions due to smoke.

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,
please refer to the Aviation Dashboard on our webpage:
https:/www.weather.gov/otx/avndashboard

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        60  96  63 100  66 103 /   0   0   0   0   0   0
Coeur d`Alene  58  92  60  96  63 100 /   0   0   0   0   0   0
Pullman        58  93  60  96  62  99 /   0   0   0   0   0   0
Lewiston       66 101  68 105  70 109 /   0   0   0   0   0   0
Colville       52  93  56  98  59 101 /   0   0   0   0   0   0
Sandpoint      54  88  56  94  57  97 /   0   0   0   0   0   0
Kellogg        62  88  66  95  68  98 /   0   0   0   0   0   0
Moses Lake     61 101  63 104  66 107 /   0   0   0   0   0   0
Wenatchee      69 101  70 103  74 106 /   0   0   0   0   0   0
Omak           64 102  66 105  69 107 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from noon Sunday to 10 PM PDT Friday for Central
     Panhandle Mountains-Northern Panhandle.

     Excessive Heat Warning until 10 PM PDT Friday for Coeur d`Alene
     Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-
     Lewiston Area.

WA...Heat Advisory from noon Sunday to 10 PM PDT Friday for Northeast
     Mountains-Okanogan Highlands.

     Excessive Heat Warning until 10 PM PDT Friday for Central Chelan
     County-Lower Garfield and Asotin Counties-Moses Lake Area-
     Northeast Blue Mountains-Okanogan Valley-Spokane Area-Upper
     Columbia Basin-Washington Palouse-Waterville Plateau-
     Wenatchee Area-Western Okanogan County.

     Heat Advisory until 10 PM PDT Friday for Western Chelan County.

&&

$$