Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
852 FXUS66 KPDT 291210 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 410 AM PST Sat Nov 29 2025 .UPDATED AVIATION...12Z TAFs...Most sites are currently VFR except KRDM and KBDN being LIFR due to low CIGs and fog/mist, respectively. KRDM and KBDN will then become VFR around late this morning. Besides low clouds, KDLS, KPDT, and KALW may see light snow and/or a wintery mix that could affect their VSBYs and CIGs around this evening into overnight (04Z-07Z) (30-40% confidence). KRDM, KBDN, and KPSC might also see low clouds returning during the aforementioned timeframe as this weak system passes through. Winds will be less than 12 kts. Feaster/97 && .PREV DISCUSSION... /issued 329 AM PST Sat Nov 29 2025/ .DISCUSSION...Dry conditions are present region-wide this morning as the forecast area is under a dry northwesterly flow aloft. 00Z and 06Z soundings from SLE, UIL, MFR, and OTX all show a bone dry layer aloft, ranging in altitude from approximately as low as 800 hPa to as high as 500 hPa. This dry layer has shown up on high- elevation, ridgetop surface observations (RAWS and CWOP) to the tune of dew points in the -15 to -30 degrees Fahrenheit range. It`s a different story in the lower levels with nighttime microphysics RGB imagery showing fairly widespread low stratus peaking out beneath scattered to broken cirrus. At the surface, some patchy dense fog has persisted in portions of central Oregon, most notably south and east of the Bend metro along US 97 and US 26. Looking ahead, ensemble guidance shows a persistent northwesterly flow aloft through the middle of the week, with a couple embedded shortwaves passing overhead. This pattern favors near- to below- normal temperatures, and some upslope snow with each passing shortwave. The first of the aforementioned shortwaves will arrive later this afternoon, passing over the Pacific Northwest overnight into early Sunday morning. The cool air mass coupled with the timing of the shortwave favor a light wintry mix for the forecast area, though ensemble-mean PWATS in HREF, REFS, and global ensembles all suggest a relatively moisture-starved system which should hinder efficient precipitation production. Recall that dry layer aloft on observed soundings? There is still a decent bit of ensemble spread among the HREF and REFS with regard to how well that layer will saturate through the late afternoon and evening. Moreover, ensemble-mean QPF has trended downward in successive runs the past 24 hours, so thinking precipitation with this system will be limited. That said, snow levels are forecast to dip down to 1000-1500 ft MSL so a dusting to an inch of snow across the Blue Mountain foothills, central and north-central Oregon, and the basins within the Blue Mountains is still a distinct possibility. NBM guidance generally paints low (less than 20 percent) chances of measurable snow in the Columbia Basin/Gorge, low-medium (10-50 percent) chances for the Blue Mountain foothills and central/north-central Oregon, and medium-high (50-90 percent) chances for the Grande Ronde Valley and Blue Mountains region. Dry conditions are expected to return by late Sunday morning, lasting into or through Monday. The second shortwave is then advertised for late Monday through Tuesday afternoon or night, with some notable ensemble spread in timing. Snow chances are reduced across the lower elevations with this system, but a better moisture tap should facilitate better chances of advisory- level snow for the Blue Mountains. By the end of the week, ensemble solutions begin to diverge with regard to pattern details, but in general a transition to a more zonal upper-level pattern is present among all ensemble clusters. As far as tangible weather, this would result in warmer, wetter, breezier conditions. && .PRELIMINARY POINT TEMPS/POPS... PDT 25 38 23 39 / 60 0 0 0 ALW 28 37 26 38 / 60 10 0 10 PSC 25 40 25 38 / 30 0 0 0 YKM 23 42 25 39 / 10 0 0 0 HRI 25 39 24 38 / 50 0 0 0 ELN 21 39 23 38 / 10 0 0 10 RDM 24 41 19 49 / 20 0 0 0 LGD 25 40 21 43 / 70 0 0 0 GCD 25 39 22 47 / 60 0 0 0 DLS 33 44 31 44 / 30 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...86 LONG TERM....86 AVIATION...97