Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 171130
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
430 AM PDT Wed Apr 17 2024

.SYNOPSIS...
Anticipate cool, brisk, and showery weather as an upper level
trough remains over the Inland NW through Thursday. The weather
gradually warms and dries for Friday. More showery conditions on
tap for late Saturday into Sunday. Then expect dry and mild
weather for early next week with above normal temperatures.

&&

.DISCUSSION...
Today and Tonight: A broad upper level trough still spans across
the region with cool and unsettled weather. Early morning
temperatures are near to below freezing across the partly cloudy
skies across the eastern third of WA and north ID with areas of
frost possible. This will be short lived as temperatures warm into
the 50s by afternoon, a few degrees milder than yesterday.
Northerly winds persist across central WA, funneling down the
Okanogan valley into the western Columbia Basin and keeping the
air mix with temperatures not as chilly.

Although the center of the main circulation has shifted east
across the Canadian prairie, cold air aloft persists with -25C at
500mb and shortwave tracking over the ID Panhandle which will be
focus for the convection today. It will be another day of
blossoming convection especially across the eastern third of WA
and the ID Panhandle with rain, snow and graupel showers. Surface
based cape peaks this afternoon across the central and southern ID
Panhandle with skinny cape aloft of 150 to 200 J/kg with
northwest shear of 10kt which could support a few lightning
strikes. Precipitation will be spotty with best chances for
wetting rain being over the ID Panhandle. Wind and shower chances
will decrease this evening, giving way to partial clearing another
chilly night across the region with risk of frost and freezing
temperatures.

Thursday and Thursday night: The upper level trough is stubborn to
depart with another weak shortwave rippling from the north and a
return of unstable conditions by afternoon. The focus will be
across northeast WA and north Idaho, although instability will be
less with surface base capes to 100 J/kg and lighter northeast
winds. Expect a return of spotty showers while dry northerly winds
continue in central WA. Daytime temperature remain cool in the
50s. Showers and winds are expected to weaken by the early evening
hours. /rfox.

Friday through Tuesday: Shortwave ridging allows for a dry and sunny
start to the weekend coupled with a warming trend. A negatively
tilted trof with a very weak and elongated moisture feed passes
through sometime Sunday/Monday and as it does it will bring an
increase in clouds and low to moderate pops over mountain locations
for light showers. This is followed up with a brief interval of
flattened upper level shortwave ridging and/or weak northwest flow
Monday that shows some amplification before the ridge axis is
displaced to Northwest Montana sometime Tuesday as moisture and
potential for minor disturbances to run through the resulting
southwest flow allow for another increase in clouds and minor
mentions of light showers over the more orographically favored
terrain. The warming trend remains in place until it is interrupted
ever so briefly with the earlier mentioned increase in cloud cover
and minor showers Sunday then it returns again into the next
workweek. Northeast winds Friday and Southwest winds Sunday may show
a tendency to be gusty as disturbances pass through. /Pelatti

&&

.AVIATION...
12z TAFS: Despite some localized river fog, mostly clear skies
will persist through 18z, before another round of convective
clouds build with a threat of showers. The area today would across
northeast WA and north ID when the atmosphere will again
destabilize from afternoon heating with another round of
rain/snow/graupel showers. This should dissipate after 02z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: The threat for IFR
conditions with fog will remain low near rivers across northeast
WA. There is high confidence in VFR conditions through the TAF
period, with one exception. Under localized moderate showers there
is a 10-20% chance of visibilities dropping to MVFR due to snow
or graupel between 20-01z Wednesday. /rfox

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

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        52  31  55  32  56  33 /  20  20  20   0   0   0
Coeur d`Alene  52  31  52  30  54  31 /  20  20  20   0   0   0
Pullman        50  30  53  31  57  33 /  10  10  10   0   0   0
Lewiston       57  35  60  35  63  38 /  10  10   0   0   0   0
Colville       55  29  55  29  57  27 /  30  10  20   0   0   0
Sandpoint      54  31  53  31  52  30 /  30  30  20   0   0   0
Kellogg        49  32  50  29  52  32 /  50  20  20   0   0   0
Moses Lake     60  33  62  36  63  38 /   0   0   0   0   0   0
Wenatchee      58  38  61  35  60  38 /   0   0   0   0   0   0
Omak           60  34  62  34  63  35 /   0   0   0   0   0   0

&&

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

$$


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