Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 230949
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
249 AM PDT Wed Jun 23 2021

.SYNOPSIS...
Today will be another warm, dry, and breezy day across much of
central and eastern Washington as well as parts of north Idaho.
Triple digit heat arriving this weekend and persisting well into
next week could rival some of the longest lasting and extreme
heat waves in the recorded history of the Inland Northwest.

&&

.DISCUSSION...

...HISTORIC AND DANGEROUS HEAT WAVE EXPECTED THIS WEEKEND AND WELL
INTO NEXT WEEK...

Today and Tonight: Dry and warm winds will once again blow across
central and eastern Washington as well as parts of north Idaho
this afternoon and evening. Southwest winds of 10 to 15 mph with
gusts to 20 mph will be common across the Columbia Basin, Palouse,
and Spokane/Coeur d`Alene areas. Localized gap winds in the
Wenatchee, Entiat, Chelan, and Vantage areas are expected to blow
in the 15 to 20 mph range with gusts to 30 mph prompting the
issuance of a Red Flag Warning for portions of Central Washington
today. Afternoon highs will once again top out in the upper 80s in
north Idaho with 90s common in central and eastern Washington.

A weak upper level disturbance tracking across central Idaho into
western Montana this morning will clip the southern and central
Idaho Panhandle this morning. Places like Craigmont, Kamiah,
Clarkia, Avery, and Mullan may experience some light rain or
sprinkles early in the day before this system moves out of the
Panhandle. Clusters of showers and thunderstorms will redevelop
this afternoon and evening over the mountainous terrain of central
and northeast Oregon and some of this activity may clip Hell`s
Canyon and parts of the Camas Prairie this evening, but the
majority of this convective activity is expected to remain over
Oregon.

Thursday: An upper level disturbance digging down the Continental
Divide on Thursday will bring a small chance of showers and
thunderstorms to the north Idaho Panhandle. Places like Bonners
Ferry, Sandpoint, Clark Fork, and Mullan will have a shot of
spotty rain and possibly some lightning in the afternoon and early
in the evening. The surface pressure gradient will become north or
northwesterly on Thursday in response to the passing upper
disturbance. North winds of 10 to 15 mph gusting to 20 mph or more
will likely develop down the Okanogan Valley. With highs in the
mid 90s around Omak and low humidity, fire spread will be a
concern with any ignitions in wind prone areas of north central
Washington.

Friday: Our highly advertised heat wave will build into Washington
on Friday, central Washington in particular. Places like Omak,
Moses Lake, Wenatchee, and Leavenworth will have a good shot of
100 degrees Friday afternoon. And the run of triple digits could
continue well into next week. North Idaho and the eastern third of
Washington will top out in the 90s Friday with hotter readings on
the way this weekend and next week. /GKoch

Saturday through Tuesday: Confidence remains high that the Inland
Northwest will experience a historic heat wave this weekend into
next week. As such, excessive heat watches have been issued for
the region. Recent model runs have been leaning towards a
persistent ridge beyond the weekend, keeping our area in the
triple digits from Saturday through at least Tuesday. We currently
anticipate that Tuesday will be the hottest day with highs
between 105 and 115 for most of the inhabited area. Is there any
relief in sight? Well... there might be a *slight* cool- down
(i.e. highs in the 90s) towards the end of next week. But this
many days out, there is still some dispute among model solutions,
some of which suggest triple digits through Thursday.

This heat event raises some concerns. This won`t just be one day
in the 100s. Multiple days in a row of these temperatures will
make heat illness all the more likely if precautions aren`t taken
because the heat will continue to stress the body each day. It
doesn`t help that our natural nighttime A/C of temperature in the
50s and low 60s will instead be in the upper 60s and 70s, posing a
problem for those who don`t have an A/C system to cool their home
(i.e. a lot of people in our area). On social media, we have been
sharing several tips to help people prepare for the event - drink
water even if you aren`t thirsty, cold water incidents can still
occur, reschedule outdoor activities, etc.

The heat will unfortunately be bad news for farmers, too. Low
relative humidities and no precipitation will worsen the already
bad drought. Plus, fuel models suggest record dryness this early
in the season, so wildfires are a concern. RC

&&

.AVIATION...
06Z TAFS: A mid-level system ejecting across SE WA/lower ID will
bring middle to high clouds into the area tonight into early
Wednesday. Isolated showers or -tsra are possible around the Blue
Mountains into the central/southern Panhandle. The risk for
impacting TAF sites is low, as most are dissipating as they
advance north. However a few could slip by south of or near KLWS.
Winds are expected to be breezy Wednesday afternoon, with gusts
near 15-20kts. The exception is near EAT where they may gust near
20-27kts. Winds start to abate through Wednesday evening, though
may hold on longer near EAT. Otherwise expect dry/VFR conditions.
/Cote`


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        90  59  90  64  93  65 /   0   0   0   0   0   0
Coeur d`Alene  88  59  87  60  91  62 /  10   0  10   0   0   0
Pullman        88  56  85  59  90  61 /  10   0   0   0   0   0
Lewiston       98  65  95  67  98  69 /  10   0   0   0   0   0
Colville       91  57  91  57  94  60 /   0   0  10   0   0   0
Sandpoint      84  56  82  58  90  59 /   0  10  20  10   0   0
Kellogg        84  61  82  63  87  65 /  20   0  10  20   0   0
Moses Lake     96  60  95  69 100  69 /   0   0   0   0   0   0
Wenatchee      94  65  94  69  99  73 /   0   0   0   0   0   0
Omak           96  64  94  67 100  69 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Excessive Heat Watch from Friday afternoon through Tuesday
     evening for Coeur d`Alene Area-Idaho Palouse-Lewiston Area.

     Excessive Heat Watch from Saturday afternoon through Tuesday
     evening for Central Panhandle Mountains-Lewis and Southern
     Nez Perce Counties-Northern Panhandle.

WA...Excessive Heat Watch from Friday afternoon through Tuesday
     evening for East Slopes Northern Cascades-Lower Garfield
     and Asotin Counties-Moses Lake Area-Northeast Blue
     Mountains-Northeast Mountains-Okanogan Highlands-Okanogan
     Valley-Spokane Area-Upper Columbia Basin-Washington Palouse-
     Waterville Plateau-Wenatchee Area.

     Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
     evening for East Washington Central Cascade Valleys (Zone
     677).

     Red Flag Warning until 9 PM PDT this evening for East Washington
     South Central Cascade Valleys (Zone 676).


&&

$$


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