Area Forecast Discussion Issued by NWS Spokane, WA
000
FXUS66 KOTX 170930
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
230 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...
06Z TAFS: Showers enhanced by afternoon destabilization have
decreased. Airports for the remainder of the night into the mid
morning will be mainly clear with light winds and good
visibility. On Wednesday, the atmosphere will again destabilize
from afternoon heating with another round of rain/snow/graupel
showers.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: 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. /GKoch
-----------------------
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.
&&
$$