Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 242329
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
429 PM PDT Tue Apr 24 2018

.SYNOPSIS...
Our warming trend will continue with afternoon temperatures
well into the 70s on Wednesday. Many lowland places in the
Columbia Basin and southeast Washington will eclipse 80 degrees
Thursday and Friday. A pattern change will bring cooler
temperatures and the threat for showers this weekend into early
next week.

&&

.DISCUSSION...
Tonight: A broad shortwave trough will push across British
Columbia and Alberta overnight. This moisture starved feature will
produce little noticeable weather change for Washington and north
Idaho. Other than some bands of thin high cirrus, this shortwave
will skirt our region with little impact. Overnight low
temperatures will fall into the low 40s with 30s in our chilly
sheltered valleys of north Idaho and northeast Washington.

Wednesday: Our high pressure ridge will amplify Wed and Wed night
leading to clear skies and warming temperatures. Temperatures
tomorrow will solidly reach the 70s regionwide. Lewiston, Moses
Lake, Wenatchee, Chelan, and Omak will get close to 80 degrees for
the first time this spring. The pressure difference between high
pressure over central/southern BC and lower pressure over Oregon
will likely produce 10-15 mph winds through the Okanogan Valley
onto the Waterville Plateau. Elsewhere, winds on Wednesday should
be less than 10mph for the majority of the day. /GKoch

Thursday and Friday: Thursday and Friday look dry and warm. 850
mb temperatures will continue to warm with Friday being the
warmest day...some 15 to 20 degrees above average for this time of
the year. Temps top out in the upper 70s to mid 80s across the
lowlands/valleys of eastern WA and north ID. Clouds will begin to
increase Friday afternoon as the weekend weather system approaches
northern California.

Saturday through Tuesday: An upper level trough will impact the
Pacific Northwest this weekend and into early next week. There is
still quite a bit of uncertainty in the forecast. The GFS
continues to take the faster, more northward track of the low,
whereas the ECMWF and Canadian are slower and further south. Agree
with WPC assessment and have trended forecast toward the
EC/Canadian blend. Saturday looks to be a more hit and miss day
for showers. One big concern is how much cooling will we see on
Saturday. For now have gone with about 10-20 degrees of cooling.
Sunday and Monday there is more of a widespread chance of rain
across the area as some wrap around energy from the low move
through. Tuesday an upper level ridge nears the west coast. There
is discrepancy on whether a wave will move down the front side of
the ridge into the Inland Northwest, which would keep showers
going for portions of eastern WA and north ID. Max temperatures
Sunday through Tuesday will be below average (in the 50s to lower
60s) while overnight lows will be at or slightly above average
(upper 30s and 40s).

Rivers will continue to run high and several are forecast to
approach flood stage with a few exceeding that. Water temperatures
are still in the 40s and hypothermia can quickly set in. /Nisbet

&&

.AVIATION...
00Z TAFS: VFR conditions will continue at all TAF sites across
Central and Eastern Washington and north Idaho through 00z
Thursday. High clouds associated with a weak system will pass
through the region through Wednesday morning before skies clear.
JW

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        44  73  45  76  49  80 /   0   0   0   0   0   0
Coeur d`Alene  41  73  43  76  45  80 /   0   0   0   0   0   0
Pullman        41  72  40  75  46  80 /   0   0   0   0   0   0
Lewiston       45  79  47  82  52  87 /   0   0   0   0   0   0
Colville       38  77  40  78  45  81 /   0   0   0   0   0   0
Sandpoint      36  70  38  73  43  76 /   0   0   0   0   0   0
Kellogg        36  70  41  74  45  77 /   0   0   0   0   0   0
Moses Lake     41  79  43  83  50  86 /   0   0   0   0   0   0
Wenatchee      46  79  50  80  53  81 /   0   0   0   0   0   0
Omak           40  79  45  80  51  83 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.

&&

$$



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