FXUS66 KPDT 211721 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1021 AM PDT Sat Mar 21 2026 .KEY MESSAGES... 1. Temperatures will return to near seasonal averages 2. Dry and cooler conditions through Monday night && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Predominantly VFR conditions are expected through the period. Some low clouds are lingering at PDT/ALW/RDM/BDN this morning in the wake of last night's cold frontal passage. Can't entirely rule out temporary MVFR (RDM/BDN) or high-end IFR (PDT/ALW) CIGs this morning into the early afternoon, but confidence is low (20-30 percent). Skies will become mostly clear for all sites by this evening, followed by increasing high-level cloud overnight into Sunday morning. Winds of 10-15 kts with gusts of 15-25 kts are forecast at all sites today, then light variable or terrain-driven winds are anticipated overnight into early Sunday morning. 86 && .DISCUSSION...issued 406 AM PDT Sat Mar 21 2026... Current radar shows a few returns over the Cascades and the Blues as the remnants of the atmospheric river remain over the area. Current ground observations show that the last hour these returns have only put down between 0.01-0.02 inches of rain. Rain is expected to continue over the mountains through today (Saturday) with rain accumulations nearing 0.05-0.1 inches in the OR Cascades and the eastern mountains through 11 PM tonight (70-90% confidence). Radar coupled with models show the majority of the perception will continue a southwest trajectory over the OR Cascades and Blue Mountains before tapering off Saturday night. Models show a weak cold front moving across the region late last night and through this morning. This will bring with it increased cloud cover as well as cooler temperatures. In house comparisons show that temperatures will decrease nearly 20 degrees from yesterday with temperatures at or near seasonal normal. With that said, NBM raw ensembles as well as HREF raw ensembles show 80-90% confidence that the Basin, Yakima, the Gorge and central OR seeing temperatures in the mid to upper 50s Saturday while elsewhere will see upper 40s to low 50s with even cooler temperatures along the higher terrains. Sunday both raw ensembles sets show temperatures to be even cooler with 70-80% of the aforementioned areas seeing low to mid 50s with isolated locations in central OR and the Basin seeing mid to upper 50s. After Sunday, models show a slow warm up through the beginning of next week. Models show persistent cool and dry weather through Monday night as southwest flow aloft continues over the area. This will slowly bring temperatures up through the beginning of the week. Models also show that precipitation will be lacking with the southwest flow keeping the region dry ahead of a pattern change with an upper level shortwave bringing in increased chances of precipitation, breezy winds and a return to cooler conditions. && .HYDROLOGY...issued 236 PM PDT Fri Mar 20 2026... The Cascade Slope basins have received the bulk of the precipitation that will be impacting river forecasts over the weekend. All tributaries with mountain headwaters will continue to run high. Forecast points along the Naches and Yakima rivers will be the most impacted by the surge of mountain runoff as several of these points enter into flood by Saturday, if not already in flood like the Naches at Naches. The Yakima River at Easton is forecast to reach just over the 52.1 ft level, (about 1 ft over moderate flood) but has a 30% chance of reaching 52ft. At Kiona, the river is forecast to reach the 13.9 ft level, but has a 10% chance of reaching 14 ft. Russell/71 && .Preliminary Point Temps/PoPs... PDT 58 30 57 33 / 80 0 0 0 ALW 58 34 57 37 / 90 0 0 0 PSC 66 33 60 34 / 50 0 0 0 YKM 63 29 56 33 / 0 0 0 0 HRI 62 32 60 33 / 70 0 0 0 ELN 54 29 52 30 / 0 0 0 0 RDM 59 24 60 29 / 20 0 0 0 LGD 56 28 58 34 / 80 0 0 0 GCD 58 29 60 35 / 60 0 0 0 DLS 60 34 61 37 / 10 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...90 AVIATION...86 HYDROLOGY...71