Marine Weather and Tide Forecast for Athol, ID

SYNOPSIS
Saturday will mark the start of a cooling and drying trend as a cold front pushes the current plume of moisture southeastward out of the region. This will bring a dry and seasonably cool weekend. Unsettled weather is forecast to return Tuesday and Wednesday as the next low pressure system brings mountain snow, lowland rain, and breezy winds.

DISCUSSION
Saturday through Monday: A cold front will slowly move southeast through the Inland Northwest Saturday morning. As of 12AM, the front is near-stationary with north-central Washington, the Columbia Basin, and northeast Washington in a post frontal environment with dew points in the low 20s to 30s. North Idaho down into the Spokane area and southeast Washington remain in the pre-frontal environment with dew points still in the 40s.

A shortwave will move onshore early Saturday morning and provide the necessary forcing to accelerate the front southeastward. This will force a band of rain from the central Idaho Panhandle into southeastern Washington. Precipitation totals will range between 0.10 to 0.20 inches across southeast Washington, the southern Panhandle, and the central Panhandle lowlands. The heaviest totals will be across the Shoshone county mountains with totals between 0.50 to 1 inches. The additional rainfall on a primed snowpack will bring rises on rivers, but flooding is currently not expected.

Much drier air will advect into the region behind the front, with PWAT values across southeast Washington and the central Idaho Panhandle dropping from over 0.70 inches early Saturday morning to under 0.30 inches by the afternoon. Not only will this bring an end to the persistent precipitation that has occurred over the Cascades and the Idaho Panhandle this past week, but it will also bring much cooler temperatures to the region this weekend. A period of dry and cooler weather through Monday will reduce mountain snowmelt rates, allowing local rivers to begin receding.

Tuesday through Friday: Active weather returns mid-week as a surface low moves up the southern edge of broader troughing in the Gulf of Alaska on Tuesday. Models are in generally good agreement with a warm front lifting north across the Inland Northwest Tuesday, bringing a return in precipitation, and then the associated cold front moving into the Inland Northwest through Tuesday night into Wednesday. There remains uncertainty in the strength and progression of the surface low Tuesday night and then another shortwave moving in on Wednesday. A weaker, more northerly track across British Columbia would favor subtle upper-level ridging and a tighter surface pressure gradient, promoting a stronger wind threat Tuesday night into Wednesday. Conversely, a stronger and more southerly primary low would diminish the ridge influence and surface pressure gradient while accelerating the arrival of the subsequent system.
This lessens the wind threat for Tuesday night into Wednesday, but increases it for Wednesday evening. Currently, the NBM gives the Inland Northwest a 50-80% chance of wind gusts greater than 40 mph on Wednesday and a 20-40% chance for gusts greater than 45 mph. Snow levels would be low enough to support snow the passes with a 50% chance for 6 inches at Stevens Pass between Tuesday night through Thursday night. This period will continue to be monitored. /vmt

AVIATION
06Z TAFS: An incoming cold front is pushing a band of moisture southeastward across the region, bringing a small chance for light rain at KGEG, KSFF, and KCOE for the next couple of hours.
Better chances exist at KPUW and KLWS between 09-15Z. VFR conditions are expected except at KPUW where MVFR conditions are favorable with preciptiation. Skies are expected to clear from northwest to southeast through Saturday morning as drier air moves into the Inland Northwest. Winds will increase Saturday afternoon with gusts 20 to 30 knots mixing down to the surface.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate confidence for MVFR conditions at KPUW with precipitation Saturday morning. High confidence for VFR conditions elsewhere.

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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 55 29 50 32 55 40 / 30 0 0 0 0 20 Coeur d'Alene 55 29 51 30 55 38 / 50 0 0 0 0 20 Pullman 52 30 50 34 54 41 / 90 0 0 0 0 20 Lewiston 59 34 56 36 58 45 / 80 0 0 0 0 10 Colville 58 28 52 30 56 36 / 20 0 0 0 0 10 Sandpoint 53 30 48 30 52 36 / 50 0 0 0 0 20 Kellogg 50 31 48 33 54 39 / 90 0 0 0 0 30 Moses Lake 58 30 56 33 58 42 / 10 0 0 0 0 10 Wenatchee 52 32 53 35 56 41 / 0 0 0 0 0 10 Omak 58 31 55 32 57 40 / 0 0 0 0 0 10

OTX WATCHES/WARNINGS/ADVISORIES
WA...None.
ID...None.