Marine Weather and Tide Forecast for Oakesdale, WA

SYNOPSIS
Temperatures will gradually trend warmer into early next week.
Active weather returns Tuesday night into Wednesday, with mountain snow, lowland rain, and breezy winds. This is expected to bring winter travel conditions over the mountain passes.

DISCUSSION

Today through Tuesday: A benign weather pattern will persist across the Inland Northwest. For this weekend, the region will be under a split-flow regime with the polar jet to the north and a subtropical jet situated over Oregon and Northern California, keeping conditions dry. High level clouds will increase this weekend as an offshore trough approaches the California/Oregon coast and spread moisture northward.
Precipitation looks to remain south of eastern Washington and the Idaho Panhandle, but there could be stray sprinkles or light rain across the Blues and Camas Prairie.

Model guidance is in good agreement regarding an upper-level ridge building into the Pacific Northwest Monday and Tuesday as the trough digs moves through southern Idaho/Nevada/Utah. This will support a gradual warming trend into the early week.
Temperatures are expected to peak Tuesday, with widespread highs in the 50s. The warmest spots will be in the lower elevations along the Snake River and in the L-C Valley where there is a 70+% chance for high temperatures of 60 or greater Tuesday afternoon.

Tuesday night through Friday: A break in the quiet weather pattern is anticipated Tuesday night into Wednesday with the arrival of an upper-level trough. Models are in great agreement on the presence of this trough, with the greatest uncertainty in the exact strength and the resulting precipitation totals and wind magnitude. A strong westerly flow will favor orographic precipitation, with the 10th-90th percentile QPF range for the mountains between 0.50 and 1.5 inches. A pronounced rain shadow is expected across the Columbia Basin and the lee of the Cascades, where totals will likely remain below 0.10 inches. For the rising terrain of far eastern Washington, totals may range between 0.10 and 0.50 inches.

Thermal profiles suggest snow levels initially near to slightly above pass level, favoring rain or a rain/snow mix at pass levels before lowering Wednesday morning in the Cascades and Wednesday evening for the Idaho Panhandle. Probabilistic snow totals for the passes remain wide due to the showery nature of post-frontal precipitation with current ranges (10th-90th percentile) between 1 to 9 inches for Stevens Pass and 1 to 5 inches for Lookout Pass. This would result in a period of winter travel conditions over the passes.

Instability will increase Wednesday afternoon as the cold pool aloft (500mb temperatures near -29°C) moves in behind the front and steepens lapse rates. Model soundings do suggest the atmosphere could destabilize enough to support charge separation with equilibrium level (EL) temperatures below -20C and some CAPE between -10C and -20C. This environment favors spring- like, graupel showers. Confidence is low in the lightning potential with a 5-10% chance for Spokane county to the central Panhandle and areas south.

A weak shortwave will quickly slide into the PNW on the leading edge of an offshore ridge into Thursday, with mountain snow showers resulting in periods of winter driving conditions over the passes. Uncertainty increases toward the weekend on the evolution of the next weather system. Models are in good agreement for the offshore ridge to nose into the PNW, bringing drier conditions late Thursday into Friday, though there could be some lingering mountain showers. Into the weekend, about 60% of ensemble members favor a stronger ridge, which would deflect the subsequent trough northward and result in a milder, drier outcome. The remaining 40% suggest a weaker ridge, allowing the trough to dig further south into the region with increased precipitation, cooler temperatures, and stronger winds. /vmt

AVIATION
12Z TAFS: VFR conditions will continue through the period with middle and high level clouds. Light surface winds.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions.

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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 50 29 51 31 52 33 / 0 0 0 0 0 0 Coeur d'Alene 48 29 51 30 52 32 / 0 0 0 0 0 0 Pullman 51 33 52 33 51 34 / 0 0 10 10 10 0 Lewiston 55 37 55 38 56 36 / 0 0 10 10 10 0 Colville 50 27 51 28 52 30 / 0 0 0 0 0 0 Sandpoint 46 28 48 29 48 33 / 0 0 0 0 0 0 Kellogg 49 31 52 33 50 33 / 0 0 0 0 10 0 Moses Lake 54 30 54 30 55 34 / 0 0 0 0 0 0 Wenatchee 54 33 52 35 56 36 / 0 0 0 0 0 0 Omak 52 30 51 33 52 35 / 0 0 0 0 0 0

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