Area Forecast Discussion Issued by NWS Spokane, WA
000
FXUS66 KOTX 121053
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
353 AM PDT Tue Mar 12 2024
.SYNOPSIS...
Another round of rain and snow lingers on through Tuesday evening
bringing additional mountain snow to the region and lowland rain.
High pressure will build over the Pacific Northwest Thursday into
next weekend bringing warmer temperatures and dry weather.
&&
.DISCUSSION...
Today through Wednesday: A Gulf of Alaska Low is pushing a cold
front through the Pacific Northwest today and early Wednesday.
Ensembles are in decent agreement with the timing of the front.
With 850mb temperatures hovering near the 0°C, it is pointing to a
mountain snow, valley rain event. The west to east trajectory of
the front puts highest snow amounts in the Cascades with near a
foot expected for Stevens Pass. The area has a 50% probability of
at least 8”. The mountains across Northern Washington and the ID
Panhandle should receive 3-6” through tonight. Precip amounts
across the region are in the 0.1-0.2” range. Models are showing
enough instability to possibly generate an isolated thunderstorm
and/or graupel over extreme Eastern WA and ID Panhandle this
afternoon. Tuesday highs will mid 40s to upper 50s. Winds will be
breezy with the frontal passage. Gusts near 30 to 40 MPH are
possible across the Basin. Overnight lows will dip into the 20s
and low 30s Tuesday night. A ridge will start to build along the
coast behind the front. It will lead to warm drying trend starting
early Wednesday morning. Lingering mountain snow showers will
slowly taper off by Wednesday afternoon. /JDC
Wednesday Night through Tuesday: Models in fantastic agreement of
a strong ridge building across the Pacific Northwest. Skies will
be clear to partly cloudy through the remainder of the week and
weekend with light winds. Temperatures will begin near average
readings Thursday, which is lows in the upper 20s and mid 30s and
highs in the upper 40s to mid 50s, and warm each day peaking
Sunday and/or Monday. By the weekend we will be looking at temps
in the upper 50s to mid 60s with lows above freezing for the
valley locations. This is 8 to 13 degrees above average.
Uncertainty enters the forecast come Tuesday with a potential
breakdown of the ridge as a trough moves down from Alaska.
Currently the ensemble clusters are showing a 60/40 split with 60%
of the models showing the ridge weakening and heights lowering
and 40% keeping the ridge going strong. There is a 20-30% chance
of showers in the afternoon across northeast WA and ID Panhandle,
but if the ridge remains it will be near zero. /Nisbet
&&
.AVIATION...
12Z TAFS: Next round of showers is currently pressing into the
Cascades. It will spread the region for the start of the period
with the back edge potentially clearing the aviation area near
15Z Tuesday. MVFR or brief IFR ceilings and visibilities and
mountain obscurations possible with the stable precip. Gusty
southwest winds follow with the passage of the back edge of the
boundary and is accompanied with some surface based convective
showers between 20Z Tuesday and 02Z Wednesday with stabilization
and decreasing clouds. Thunderstorm potential across the region
is around 20-30%. Wednesday morning fog could generate brief IFR
conditions for the northern valleys and DEW.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Moderate to high confidence in MVFR conditions with precipitation
onset in more stratiform rainfall through Tuesday afternoon and
evening gusty southwest winds. Low confidence on thunderstorms
impacting airfields. Low confidence for fog bringing IFR
conditions into the Spokane area. Localized radiational fog could
bring brief reduced visibilities to GEG-SFF-COE.
------------------------
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 49 29 47 28 51 29 / 80 30 0 0 0 0
Coeur d`Alene 46 28 43 25 48 28 / 90 50 10 0 0 0
Pullman 47 29 43 28 49 29 / 80 50 10 0 0 0
Lewiston 54 34 50 32 54 34 / 70 20 0 0 0 0
Colville 46 26 48 25 50 27 / 70 50 0 0 0 0
Sandpoint 42 29 41 27 46 28 / 90 70 20 0 0 0
Kellogg 43 30 40 26 46 29 / 100 80 30 0 0 0
Moses Lake 54 29 53 29 56 32 / 30 10 0 0 0 0
Wenatchee 49 32 51 33 55 36 / 30 0 0 0 0 0
Omak 52 30 53 32 56 35 / 30 10 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT this morning for Central
Panhandle Mountains.
WA...Winter Weather Advisory until 11 AM PDT this morning for
Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for Western
Chelan County.
&&
$$