Area Forecast Discussion Issued by NWS Spokane, WA
000
FXUS66 KOTX 180923
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
223 AM PDT Mon Mar 18 2024
.SYNOPSIS...
High pressure will persist over the Pacific Northwest, keeping the
region warm and dry through the first half of the week. Over the
second half of the week, temperatures will cool and chances of
lowland rain and mountain snow will return through the weekend.
&&
.DISCUSSION...
Monday and Tuesday: If you didn`t have a chance to get outdoors over
the weekend, you still have time! Sunshine, blue skies, and warm
weather will stick around through the first half of the week due to
a ridge of high pressure remaining planted over us. Daytime highs
Monday and Tuesday will be well above normal for this early in the
year, with afternoon temperatures in the upper 60s to mid 70s
expected regionwide. Typical highs for the Inland Northwest in late
March range from the upper 40s to mid 50s, so we`ll be running about
20 degrees warmer than that. Overnight lows will dip into the upper
30s and 40s - still chilly enough that you`ll want to pack a jacket
if you`re headed outside early in the morning before things have a
chance to warm up. Patchy ground fog may develop each night in
sheltered valleys and near bodies of water, but any fog that does
develop won`t last long after sunrise. Heading into Tuesday night, a
system will move in from off the Pacific, pushing our ridge of high
pressure eastward and bringing a pattern change for the second half
of the week. /Fewkes
Wednesday through Sunday: As the upper level trough digs south along
the west coast, a surface High will slide into Alberta. This will
create a tight pressure gradient across the Northwest and enhance
southwest winds through the Columbia Gorge, the southern Basin, and
into the Palouse on Wednesday. Breezy winds with gusts 25-30 mph
will be common, however when referencing the situational awareness
guidance for how this compares to climatology or how "out of the
norm" this pattern is for impactful wind, nothing shows up. The
impact seems fairly low for wind during this time, Wednesday and
Thursday.
The flow will begin to shift more westerly and northwesterly late in
the week with a more unsettled and active period taking shape,
leaving the upper level trough just off shore for a prolonged period
of time.
Saturday we begin to see cooling aloft and the unstable, energetic
disturbance impact the precipitation forecast across the Inland
Northwest. Friday into Saturday the precipitation potential will
become more widespread, with QPF amounts having taken a notable
increase with this forecast package. During the day Saturday is when
model guidance increases the snowfall potential as well. Given our
sun angle this time of year, I can`t imagine much of the snow
accumulation will stick around long on the road surfaces and
untreated areas below 3500 feet. For mountain passes, roads may
become challenging to travel on for a period of time. So taking
caution with a return to winter driving conditions should be noted.
However, the impacts from snow accumulation over a longer period
could also play into a low impact event. This longer duration event
could produce 6-10 inches of snow at regional mountain passes and a
dusting to 2 inches for northern valley locations (Friday through
Sunday). Lookout Pass: 35% chance for more than 8"; Stevens Pass:
30% chance for more than 8".
Not to be outdone by our change back to non-Spring time temperatures
for next weekend, the NBM guidance is also giving us about a 10-15%
chance for thunderstorms late in the week, Friday into Saturday, for
far eastern Washington/ north Idaho. The instability from cold air
aloft and deep mixing to the surface with an unstable disturbance
makes sense. Confidence is not very high in this given forecast
element, so we will continue to monitor this. /Dewey
&&
.AVIATION...
06Z TAFS: High pressure will result in VFR conditions regionwide
for the next 24 hours. Some shallow patchy fog is possible in the
early morning hours in the sheltered valleys, especially near
bodies of water, including in the vicinity of KSFF.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in
VFR conditions. Low confidence in patchy fog reducing visibility
near SFF around 12-16Z Monday.
------------------------
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 71 41 69 43 60 39 / 0 0 0 0 10 10
Coeur d`Alene 71 40 69 42 57 39 / 0 0 0 0 20 20
Pullman 69 34 67 36 58 41 / 0 0 0 0 10 20
Lewiston 71 48 70 50 66 44 / 0 0 0 0 10 20
Colville 73 35 71 37 59 35 / 0 0 0 0 30 20
Sandpoint 64 33 62 35 55 39 / 0 0 0 10 40 50
Kellogg 67 41 65 43 57 41 / 0 0 0 0 20 30
Moses Lake 73 42 71 44 65 40 / 0 0 0 0 0 0
Wenatchee 71 49 69 47 61 41 / 0 0 0 0 0 10
Omak 73 43 71 45 65 39 / 0 0 0 0 10 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$