Marine Weather and Tide Forecast for Moscow, ID

SYNOPSIS
A series of very wet and warm systems will move through the Inland Northwest through the middle of next week. This will result in warmer than normal temperatures, periods of heavy mountain rain, high mountain snow, and lowland rain. Strong west to southwest winds are expected Monday evening into Tuesday.

DISCUSSION
Saturday Night through Sunday: The Inland Northwest remains in the wake of today’s passing front, which brought drier conditions and sunshine to much of the Inland Northwest. Breezy west to southwest winds of 20-40 mph across the Basin, Spokane area, and Palouse are the result of steep low-level lapse rates mixing 35-40 mph winds from 850 mb to the surface. Winds will ease this evening after sunset.

A conditionally unstable airmass combined with moist upslope flow continues to produce orographically enhanced showers over the mountains, including snow at Stevens and Lookout Passes.
Temperatures near 32-34F are limiting road accumulations.

A series of weather systems begins early Sunday as the parent surface low and its occlusion move into the central BC coast.
Guidance shows a secondary low developing off the WA coast, lifting a warm front and a new moisture plume into the region from the south. Snow levels will be high, favoring lowland rain and high mountain snow. The exception will be across the northern valleys where cold air remains trapped. The Methow Valley has held near freezing all day today under persistent low clouds, and warm-frontal precipitation may fall as snow, which models typically handle poorly.

Monday through Thursday: A long-duration atmospheric river targets the Pacific Northwest. From Monday into Tuesday, strong westerly flow will focus precipitation over the mountains and far eastern Washington. Ensemble agreement continues for a deepening surface low tracking through southern BC. With precipitable water 250–350% of normal, expect heavy mountain rain, increasing concerns for rises on small streams and localized mud/rock slides on steep, snow-free slopes.

For eastern WA and north ID, the primary hazard Monday night into Tuesday will be strong winds as the cold front pushes through and the low deepens into southern Alberta. A tightening southwest pressure gradient and 850 mb winds of 40-55 kt support the following wind probabilities from the NBM for the Columbia Basin, Blue Mountains, Palouse, and Spokane area: a 50-70% chance of gusts greater than 45 mph and a 30-40% chance of gusts greater than 55 mph.

A brief break in precipitation is expected early Tuesday as the moisture plume sags south into Oregon. Beyond that, guidance diverges Tuesday night through Thursday regarding the next low’s track into BC, which will dictate how far north the plume returns. If the plume stays farther south, precipitation totals would fall in the lower end of the spectrum, though a further northward placement would continue to pile on the rain totals into the mountains. This timing and placement will be refined in the coming days.

Friday and Saturday: Ensembles begin to hint at a break in the pattern Friday into the weekend with a majority of ensemble guidance (~80% of GEFS/ECMWF/CMC members) favoring an amplifying ridge building over the PNW. However, this comes with some uncertainty as ~20% of solutions support a colder trough instead. /vmt

AVIATION
00Z TAFs: Breezy west to southwest wind gusts 20-30 knots (25-40 knots for KPUW/KLWS) will continue through the mid afternoon before gradually decreasing this evening. The next round of precipitation will move in from the south Sunday morning with a warm front. Precipitation will begin first to KEAT/KMWH around 12-15Z, spreading north into the rest of the area through the morning. Models have moderate to high confidence for at least widespread MVFR/IFR conditions redeveloping after 08Z for KGEG/KSFF/KCOE/KPUW and after 15Z for KLWS/KMWH/KEAT. KGEG/KSFF/KCOE also carry moderate confidence for IFR conditions after 12Z.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate to high confidence in the return of widespread MVFR/IFR conditions Sunday morning and into the afternoo

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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 44 34 44 39 50 41 / 40 10 90 50 90 90 Coeur d'Alene 40 34 43 39 48 41 / 70 30 90 80 100 100 Pullman 45 38 45 41 50 42 / 60 30 90 80 100 100 Lewiston 57 40 49 43 53 48 / 50 30 80 70 90 100 Colville 37 24 39 31 46 32 / 50 10 100 50 90 80 Sandpoint 39 31 41 36 45 38 / 90 40 100 90 100 100 Kellogg 40 36 41 39 47 41 / 100 80 100 100 100 100 Moses Lake 55 36 49 37 52 41 / 10 10 80 10 70 60 Wenatchee 53 38 46 39 51 41 / 20 30 90 30 80 80 Omak 40 31 41 34 44 34 / 20 10 90 20 70 80

OTX WATCHES/WARNINGS/ADVISORIES
WA...None.
ID...Winter Storm Warning until 4 PM PST this afternoon for Central Panhandle Mountains.