Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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183 FXUS66 KPDT 200936 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 236 AM PDT Fri Sep 20 2024 .SHORT TERM...Today through Sunday...A shortwave trough is passing through western Canada this morning placing the Pacific Northwest under a northwest flow. Its main impacts will be some breezy winds and cooler temperatures today close to near normal. Strongest winds will be confined to the eastern Columbia River Gorge and the Kittitas Valley with sustained 20-25 mph and gusts 30-35 mph. A flat ridge of high pressure will begin to move over the region from the eastern Pacific late today through Saturday. This will bring lighter winds to the entire forecast area while keeping temperatures near normal. Another weak upper level trough will move into western Canada on Sunday. There could be a few light showers in the central Washington Cascades otherwise conditions remain dry. It will bring another increase in breezy winds mainly along the east slopes of the Cascades and most noticeably to the eastern Columbia River Gorge and Kittitas Valley similar today todays wind speeds. .LONG TERM...Monday through Friday...The long term remains quiet with high pressure ridging taking control of our region, bringing an extended period of null precipitation chances and above normal temperatures before shifting eastwards with temperatures then expected to return back to near normal, albeit with precipitation still locked to the western side of the Cascades. Monday begins with the aforementioned upper ridge extending from the Pacific over our region, and then continuing to shift eastwards through the middle of the week. This will allow for a dry and benign start to the work week while temperatures steadily increase. Highs for our population centers begin in the upper 70`s to the low 80`s on Monday, but by Wednesday most locations will be in the mid 80`s and portions of the Columbia Basin may even be flirting with 90 degrees. The NBM overall isn`t excited about the prospect about us getting quite that warm though, with only a 15-20% probability of highs 90+ on Wednesday. Meanwhile on Wednesday, the upper low will continue to shift eastwards as a deep trough swings down from the Gulf of Alaska region and across the PacNW and eastern Canada. The majority of the energy from this system should stay north of us in Canada itself, but ensembles indicate that our flow becomes more zonal thanks to the troughing, helping to bring our temperatures back down closer to near normal by next Friday. Unfortunately this flow does mean any moisture coming onshore is going to get stuck on the windward side of the Cascades, possibly making it just over the crests, but don`t expect much with only a slight chance to chance of scattered showers Wednesday evening through Friday morning on the lee side of the mountains. Overall, there is moderate to high confidence (60-70%) in the forecast, with confidence lowering towards the end of the period as ensemble clusters show some variation in how we can expect the above systems to evolve, but not enough to significantly drop expectations. Should be a quiet week of warmer fall temperatures overall. Goatley/87 && .AVIATION...12Z TAFs...VFR conditions expected over the next 24 hours, though some smoke may creep back into Central Oregon and allow for some light haze in BDN/RDM, but MVFR conditions not expected. Sustained winds 10 knots or less all sites, with some breezy gusts 15-20 knots for DLS/BDN/RDM/PDT through tomorrow afternoon. Goatley/87 && .PRELIMINARY POINT TEMPS/POPS... PDT 71 43 71 43 / 0 0 0 0 ALW 73 48 73 46 / 0 0 0 0 PSC 76 49 75 49 / 0 0 0 0 YKM 76 44 75 46 / 0 0 0 0 HRI 76 46 75 46 / 0 0 0 0 ELN 71 46 74 47 / 0 0 0 0 RDM 72 37 72 39 / 0 0 0 0 LGD 68 41 71 41 / 0 0 0 0 GCD 71 39 71 40 / 0 0 0 0 DLS 74 50 78 50 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...91 LONG TERM....87 AVIATION...87