Marine Weather and Tide Forecast for Spokane Valley, WA

SYNOPSIS
A warmer and periodically breezy pattern settles in for much of the work week. Snowmelt combined with moderate to heavy precipitation in the North Cascades and light precipitation over the Idaho Panhandle mountains will lead to rises on rivers.

DISCUSSION
Today through Friday: The longwave pressure pattern over Contiguous U.S. will remain static through the work week as a blocking high pressure ridge pattern dominates over the western U.S. An active Polar Jet Stream will steer an Atmospheric River (AR) into the southern BC and across the northern Washington Cascades and North Idaho at times. Moisture with this AR will focus a lot of precipitation west of the Cascades, but much less in the way of precipitation is expected across Eastern Washington and the Idaho Panhandle. Nothing like what we experienced last week into last weekend when the AR was zonal and packed a wallop with snow and heavy rain impacts. Another distinction with this AR is that the Inland Northwest will remain within the warm sector for this entire period. Warm, moist air will result in cloudy but mild days and mild overnight as well with the absent of good radiational cooling taking place. High temperatures warm up into the upper 50s to low 7s by Wednesday through Friday, and overnight lows only cool down into the upper 40s to low 50s for many places. The Cascade crest looks to pick up 3+ inches of precipitation through Wednesday. The Idaho Panhandle will see precipitation increasing through the day today and continue into Tuesday night and early Wednesday. Precipitation accumulations will be lower over the Idaho Panhandle with between a tenth to up to around a half of an inch in the valleys. Orographics will play a roll in generating more precipitation up to around an 1- 1.5 inches for the Selkirks and Cabinets. Snow levels will be above 7,000 feet with all of this falling as rain even for our higher elevations. Rises on rivers will be a concern, and that will occur primarily just from snowmelt. There doesn't look to be enough contribution from rain in the Panhandle for flooding impacts to be a concern. Stehekin will be different as it is expected to see a steady rise this week with rising water impacting the community there.

Friday night through Tuesday: A cold front will push through late Friday. Model ensembles don't indicate a strong cold front passage.
The 00Z deterministic GFS model looks too strong compared to the ensembles and winds are muted compared to what this one deterministic guidance is indicating. Winds are expected to pick up with the front, but early indications is that they won't be necessarily impactful. The cold front will bring precipitation along with it and cool temperatures into the weekend back towards normal with highs back in the 50s and lows back into the lower 30s. We also lose the Pacific moisture tap behind the cold front passage with a period of drier condtions around Saturday or Saturday night into early next week. /SVH

AVIATION
18Z TAFS: The plume of moisture directed at the region will oscillate up and down over the Inland Northwest bringing intermittent chances for light rain. While cloud cover will remain extensive through the TAF period, warm air advection will keep ceilings above 4k feet AGL at all terminals. Southwesterly winds will pick up this afternoon and remain breezy through Wednesday morning with gusts up to 25 kts, particularly for KGEG, KSFF, KPUW, and KMWH. The persistent elevated winds overnight will keep the boundary layer well-mixed, staving off development of fog or low stratus.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions through the forecast period.

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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 57 47 61 49 64 50 / 20 60 20 20 20 20 Coeur d'Alene 53 44 58 45 62 47 / 40 80 40 40 30 30 Pullman 57 44 61 48 66 49 / 30 30 10 10 10 10 Lewiston 63 45 69 48 72 52 / 20 20 0 10 0 10 Colville 58 44 62 44 63 46 / 10 50 30 20 30 20 Sandpoint 50 42 53 44 57 44 / 50 90 70 60 60 50 Kellogg 49 45 54 47 58 48 / 70 90 50 50 40 40 Moses Lake 67 48 69 49 71 50 / 10 20 0 0 0 0 Wenatchee 64 49 65 49 66 50 / 30 40 30 10 20 20 Omak 63 45 66 47 66 48 / 10 30 20 10 20 20

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