Marine Weather and Tide Forecast for Moscow, ID

SYNOPSIS
Active weather continues with rain and mountain snow through Monday. Dry weather returns Tuesday and Wednesday, then another system moves in toward the end of the week.

DISCUSSION
Today: The frontal boundary associated with the trough is moving northward and into the forecast area, bringing rain to the lowlands and snow to the mountains. While there was initially potential for the lowlands to get snow, thermal profiles have warmed enough to result in nearly all rainfall. Much of the rain associated with this system will fall by this afternoon into evening, with system totals 0.10-0.5 inches. Highest PWATs at 200-250% of normal associated with the moisture plume are in the southeastern portion of the forecast area, where higher rainfall totals are expected. HRRR probabilities show Central Idaho Panhandle, Lewiston, and Pullman areas have a 70- 80% chance and above at seeing 0.25 inches of rain. For Spokane, there is a 30-40% chance of only 0.10 inches of rain, with chances decreasing sharply for locations further north.

Biggest impacts with this system will be wintry travel conditions along mountain passes, particularly in the Idaho Panhandle. Lookout Pass has a 60-70% chance of seeing 5 or more inches of snow. This has resulted in a Winter Weather Advisory for the Central Panhandle Mountains through 10am this morning. The Cascades will see snow to a lesser extent, with Stevens Pass having a 60-70% chance of 3 inches of snow or more.

Tuesday through Thursday: Once this system moves out of the area, low pressure systems passing to the north and south of us will result in mostly zonal flow, leading to dry conditions through Thursday. Temperatures remain slightly above average, reaching high 30s to mid 40s during the day and dropping to the high 20s to low 30s overnight.

Friday through Monday: The aforementioned low pressure system to the north of us will begin to strengthen and drop southward down the Canadian coast, leading to another round of precipitation through the weekend and into early next week. Long-range NBM probabilities show a 20-30% chance and above at the forecast area seeing 0.10 inches of precipitation. However, colder air advected into the area will result in lower snow levels and increased chances for lowland snow. Mountain snow totals right now look light through Monday, with 3-4 inches expected at highest elevations.

Things begin to get interesting further into next week. Clusters unanimously show the low pressure system deepening significantly off the coast, which would result in further rounds of precipitation alongside cooler temperatures. The CPC's 6-10 and 8-14 Day Outlooks show increased chances of higher than normal precipitation and near normal to leaning below normal temperatures. Due to the drier start to our snowpack this winter, this will be something to keep a close eye on as the week progresses. /AS

AVIATION
12Z TAFS: Radar shows the backside of precipitation moving through eastern Spokane County and western Whitman County, with rain ending shortly at KGEG/KSFF and tapering at KPUW and KCOE through 15-18Z. Expect a mix of conditions through the morning with LIFR fog in central Washington and IFR and MVFR ceilings across far eastern Washington and north Idaho. Models indicate gradual improvements to VFR or high MVFR through the afternoon as relatively drier air filters into the Inland Northwest and boundary layer mixing increases. Winds will relax tonight with clearing skies, creating a favorable environment for fog and stratus development in central Washington, the northern valleys, and around KGEG/KSFF/KCOE. Boundary layer winds shift to the east between 03-09Z, which will suppress development at KPUW.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for widespread IFR/MVFR conditions through this morning with gradual improvements to VFR through the afternoon.
Lower confidence in KCOE improving to VFR with models indicating a 40 percent chance or greater for MVFR conditions to remain through the period. Additionally, timing of improvement to VFR at KPUW will depend on the shift to easterly boundary layer winds, which could be delayed by a couple hours than what is in the TAF.

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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 42 30 44 28 44 28 / 20 0 0 0 0 0 Coeur d'Alene 41 30 44 27 44 27 / 60 10 0 0 0 0 Pullman 41 30 44 30 42 30 / 60 10 0 0 10 0 Lewiston 48 32 48 33 45 33 / 50 0 0 0 10 0 Colville 42 27 43 25 44 25 / 10 0 0 0 0 0 Sandpoint 39 31 42 28 42 27 / 50 20 10 0 0 0 Kellogg 38 29 43 28 43 27 / 90 40 0 0 0 0 Moses Lake 48 28 48 28 48 28 / 10 0 0 0 0 0 Wenatchee 47 31 42 30 46 31 / 10 0 0 0 0 0 Omak 43 31 42 28 45 29 / 0 0 0 0 0 0

OTX WATCHES/WARNINGS/ADVISORIES
WA...None.
ID...Winter Weather Advisory until 10 AM PST this morning for Central Panhandle Mountains.