Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
666 FXUS66 KPDT 020550 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 950 PM PST Mon Dec 1 2025 .Updated Aviation Discussion. .AVIATION...06Z TAFS...VFR conditions currently across all sites, with the only exception being IFR at KPSC due to reduced ceilings of 700 feet. Conditions are expected to degrade to MVFR for KDLS/KPDT/KALW Tuesday afternoon/evening as a result of an incoming system. KALW is expected to experience a period of light snow this morning, leading to MVFR conditions due to reduced visibilities of 4SM and ceilings of 2.5kft until late morning. Winds will stay light and below 10 kts across all terminals. 75 && PREV DISCUSSION... /issued 233 PM PST Mon Dec 1 2025/ DISCUSSION... Light snow is expected (40-90%) This evening through Tonight across the Eastern Columbia Basin and foothills of the Blue Mountains though the Northern Blues and Wallowas, creating winter weather conditions. Lower elevations might only get a dusting or more of snow but the snow amounts quickly ramp up with higher elevations. A frontal system moving though This afternoon and Tonight will be the initial strong orographic forcing impetus, followed by persist northwesterly momentum behind the system continuing to promote light precipitation in the dendritic growth zone beyond 24 hours, driving high mountain areas well above 6 inches of snow with time. Latest HREF ensemble mean hourly trends begin Northern Blue Mountains snow in earnest around 8z/or late evening, with snow continuing through late afternoon Tuesday. For Wallowa county where 4 inches is the lower end for advisory, snow chances for 4 inches or more below 5400 ft are quite low (20 percent or less across the majority of that area). The Northern Blue Mountains of Oregon (OR502) have a higher minimum requirement of 6 inches for advisories. In either case the probabilities for this magnitude of snow is not meeting in 12 hours. One local community with a greater risk of some snow imp- acts is Tollgate where there is a 70% chance of 5 inches of total snowfall, and about a 50% chance to hit or exceed the low end 6 threshold for advisories. Friday through the weekend look to be a windy period with southwest winds increasing Friday evening, remaining windy overnight and and not appreciably diminishing until Saturday evening. Winds will pick up again diurnally Sunday, based on NBM trends for this period. This change to a downslope windy regime will lead to a more marked warmup on Friday where NBM is forcing low to mid 50s across much of the Lower Columbia Basin, Blue Mountain foothills, central Oregon and the John Day Basin. Russell/71 && .PRELIMINARY POINT TEMPS/POPS... PDT 29 40 27 40 / 20 60 10 0 ALW 30 38 29 38 / 40 70 10 10 PSC 25 39 24 37 / 20 30 0 0 YKM 24 45 24 38 / 10 0 0 0 HRI 27 41 26 38 / 20 40 0 0 ELN 25 44 22 37 / 10 10 0 0 RDM 26 46 21 46 / 0 10 0 0 LGD 31 41 27 41 / 40 90 20 0 GCD 30 42 27 43 / 10 50 10 0 DLS 34 51 34 43 / 10 20 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ DISCUSSION...71 AVIATION...75