146 FXUS66 KOTX 060938 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 238 AM PDT Wed Oct 6 2021 .SYNOPSIS... A cold front will bring a chance for light showers and more importantly, usher fall-like temperatures into the region today. Look for these cooler conditions to continue for the remainder of the workweek. Many locations will experience near or below freezing overnight temperatures starting Thursday morning onward. The next round of showers and breezy winds looks to be by next Sunday. Cool, quiet weather expected for start of next week. && .DISCUSSION... Today through Friday: The Inland NW will get its first taste of autumn over the next few days as an upper-level trough migrates into the region and remains stationary throughout over the next several days. The most noticeable change will be with our temperatures. Over the last few days, the region has been downstream or out ahead of this system which resulted in mild southerly flow, 850mb temperatures of 14-15C, and temperatures in the 70s. Starting today, 850mb temperatures will cool to around 5C and afternoon highs will only top out in the 50s to lower 60s. The average high temperature for Spokane is 64F today, so temperatures were running nearly 10F above normal on Tuesday and will be roughly 5F below normal today. Needless to say, may want to grab a light jacket before heading out this morning. As of 2AM this morning, the trough was already into Western WA and continuing to drift eastward. The system is under-going meridional stretching which is helping to slow and weaken the system. The system will also lose ties to any appreciable moisture. Radar indicates the leading cold front has crossed into Central WA and stretches from Tonasket, WA to Yakima, WA at hour. Scattered light sprinkles or brief showers developing along and out ahead of the the front will continue until the front moves through but will only equate to rainfall amounts between a trace and 0.03". Additional showers will form along the Cascade Crest and expand into the North Cascades of northern Chelan and Western Okanogan Counties at times this afternoon. These are being driven by a few hundreds joules of CAPE under the upper- level cold poor. A few of these showers could be moderate at times near the Cascade Crest and drive snow levels down to 4000 feet. Outside the potential for an organized Puget Sound Convergence Zone (PSCZ), this activity will be isolated to scattered and very unorganized. The aforementioned PSCZ will stand a decent chance for impacting the Cascade Crest over western Chelan County. We are observing breezy southwest to west winds this morning. Wind gusts have been between 15-25 mph. Expect this trend to continue through this morning as the front passes through then winds will begin to weaken in the afternoon with gusts decreasing closer to 15 mph. The trough will remain over the region Thursday and Friday with minor fluctuations in day to day temperatures each afternoon. The air mass will become drier with precipitable water values lowering near 0.30" or lower. The drier and cooler air combine with clearing skies each Thursday and Friday mornings' will bring the potential for chilly morning lows. Many areas will carry a risk for freezing temperatures. Those of you still nursing a garden should be prepared for a shift in the weather pattern and potential for freezing temperatures. A hard freeze will be possible across our sheltered northern valleys where temperatures could tumble into the mid to upper 20s. May want to consider winterizing any sensitive irrigation equipment in these areas. /sb Saturday: A brief weak ridge is expected to be in the region as the trough shifts East. Widespread early morning frost is expected across the Basin as overnight lows dipped into the upper 20s and low 30s. Winds will be a little breezy across the Basin with gusts near 20 MPH. Temperatures will be similar to the previous couple of days. Sunday through Wednesday: A Low is expected to drop into the Pacific Northwest from the Gulf of Alaska and bring a decent chance of widespread showers across the region. The areas with the highest amounts are the Cascades and Idaho Panhandle with 0.25"-0.5" possible. The rest of the region can expect a tenth or two. Snow levels will be dropping near 3000ft and depending on the timing of precip, locations could be impacted by a rain-snow mix particularly in the high terrain of the Cascades. Accumulation is not expected to much as ground temperatures are expected to be above freezing. As of now, the best potential will be for the Cascades and Idaho Panhandle during the Sunday into Monday overnight. Sunday is still expected to be be breezy as the cold front moves through the region. The Basin winds have weakened from previous runs but still expected to be near 20 mph sustained with gusts into the mid 30s during the late morning and early afternoon period. Monday and Tuesday can expect diminishing mountain showers as drier air moves in behind the Low. A ridge pattern will build into the region. temperatures are expected to be in the 40s and low 50s for the highs and upper 20s and low 30s for the lows. An incoming late Tuesday into Wednesday is expected to bring another round of precip to the region. With little change in the overall trend, it could bring some of the first snow to the northern valley locations and reach as far South as Hwy 2. But this is very far ahead and has little confidence for now. /JDC && .AVIATION... 06Z TAFS: VFR conditions with thick mid-to-high level clouds will continue through the early afternoon. Winds will relax tonight, but will pick up again for a breezy afternoon across the Basin, Palouse, and West Plains. Scattered light showers will continue to move across the region with the cold front's passage. JS && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 35 59 31 59 34 / 20 0 0 0 0 0 Coeur d'Alene 57 34 58 31 58 34 / 30 0 0 0 0 0 Pullman 52 31 57 31 58 32 / 30 0 0 0 0 0 Lewiston 59 39 63 40 63 40 / 40 0 0 0 0 0 Colville 61 31 59 27 59 27 / 20 0 0 0 0 0 Sandpoint 55 32 55 29 56 29 / 20 0 0 0 0 0 Kellogg 52 36 56 36 58 37 / 30 0 0 0 0 0 Moses Lake 62 33 60 32 60 32 / 0 0 0 0 0 0 Wenatchee 61 39 60 40 61 40 / 0 0 0 0 0 0 Omak 64 35 61 34 61 35 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$