National Weather Service Spokane WA
351 AM PST Fri Jan 24 2020

.SYNOPSIS...
A mild and active weather pattern is expected into next week
with several rounds of mainly valley rain and mountain snow.

&&

.DISCUSSION...
Today through Sunday: The mild and wet pattern continues with a
series of waves tracking into the region from the southwest.

Today: The first system in the form of an occluded front will
track across Eastern Washington and North Idaho this morning
bringing widespread rain and high mountain snow. Behind it
westerly flow will lead to a drying trend over Central WA by early
morning and across much of Eastern WA late morning or early
afternoon while showers will be more prevalent in the Cascades and
Idaho Panhandle. Breezy winds across the Columbia Basin behind
the front combined with mild 850mb temperatures around 2C should
translate to mild temperatures in the mid 40s to low 50s for
highs.

Tonight and Saturday: A mid level wave passing through tonight will
keep showers persisting across the ID Panhandle and Cascades with
snow levels dropping to around 3000 feet. Light accumulations are
possible in the mountains. On Saturday yet another wave reaches
Central WA in the morning and then NE WA/N Idaho late morning into
the afternoon. Precip amounts are light, but could lead to a
rain/snow mix northern valleys and Cascade valleys and valley
rain/mountain snow elsewhere.

Saturday night and Sunday: A stronger system arrives as a surface
low deepens to around 995mb as it tracks north near or just off
the WA coast. This is expected to bring widespread precipitation
into the region especially overnight Saturday night into Sunday
morning with snow levels ranging from 3000-5000 feet for most of
the area resulting in valley rain and mountain snow. Snow levels
could begin lower however along the East Slopes of the Cascades.
In addition an easterly pressure gradient over the area will
provide increased isentropic ascent and precipitation amounts for
the Cascades. Moderate snow accumulations of 6 to 10 inches are
likely in the mountains. Snow amounts around Winthrop, Stehekin,
and Lake Wenatchee are a tougher call as surface temperatures may
have a hard time dropping down to freezing Saturday night before
precipitation arrives due to abundant boundary layer moisture and
stratus limiting temperature falls. Most model guidance suggest
the Methow Valley will be cold enough for snow, with a rain/snow
mix more likely for the Leavenworth and Lake Wenatchee areas. Wet
snow may also occur on the Waterville Plateau and near the
Canadian border before snow levels rise. Accumulations in these
areas should be light. As the low weakens and tracks into British
Columbia on Sunday mild southwest winds again develop across the
Columbia Basin, Spokane area, Palouse, and LC Valley with highs
again very mild in the mid 40s to near 50. JW

Sunday night through Friday: Subtle change in the overall weather
pattern for the start of next week. Instead of weather systems
coming at us from the southwest, they will be more from the west.
Thus they will be a little cooler, for a little better chance of
low-elevation snow, mainly in the late night and morning hours.
Not looking for anything appreciable even if it does occur.

Looks like there might be a brief break in the precipitation
around Tuesday night or Wednesday. But another even warmer system
moves in around Thursday. Snow levels in the Panhandle rise to
about 5000 feet.

The cold front that comes through the region on Thursday night and
Friday could be a windy one. Not much computer model agreement on
it at this point, but some ensemble members show the potential for
a high wind event. Too far out in the forecast to get into
details, but it will bear watching. RJ