Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
803 FXUS66 KPDT 291832 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1032 AM PST Thu Jan 29 2026 .UPDATE (10 AM PST)...Winter weather advisory for freezing rain cancelled owing to increasing temps, 1-3 degrees, over the last hour with limited impacts apparant based on DOT reports. Warm road temps seen with MRMS probs of subfreezing road temps have crashed with little evidence to support icing. Meantime, shower activity is limited with little reaching the ground and scant spill over into the eastern slopes of the WA Cascades. Forecast updated to reflect this. Otherwise, going forecast largely on track with multiple weak disturbances bringing chances for mainly rain, highest along the crest of the WA Cascades, tonight and late tomorrow. && .DISCUSSION... Key Messages: 1. Widespread precipitation today, freezing rain possible. *Winter Weather Advisories Active* 2. Mountain precipitation Friday, returning Sunday and Monday. 3. Warming trend through Saturday and staying above normal. Current radar and infrared satellite imagery shows light returns extending across the east slopes of the Cascades and into the Columbia Basin under mostly cloudy skies. This is in response to an incoming shortwave and weak frontal system that is flattening the upper level ridge that developed across the area on Wednesday. The previously positioned ridge has allowed temperatures to drop to near or slightly below freezing across portions of the Lower Columbia Basin and the Yakima/Kittitas Valleys, which will provide the potential for freezing rain to occur as the weak warm front passes through the area this morning. The best chance for freezing rain to occur and result in ice accumulations of between 0.03- 0.10" will be across the Kittitas Valley (60-70% chance), with much lower chances extending into the Yakima Valley (20-40% chance), Tri-Cities (10-20% chance) and the Hanford (15-25% chance) area. Thus, Winter Weather Advisories have been issued across the Kittitas Valley and the Upper/Lower east slopes of the Washington Cascades until noon. Slick roads are expected through the morning hours, so use caution and provide additional time if traveling. Due to the passing warm front today, snow levels will be increasing from 4500-5500 feet this morning to 5500-6500 feet tonight, leading to snowfall at higher elevations across the Cascade and Blue Mountains and pass-level rainfall. Moisture is lacking with this system as the upper level ridge continues to build during the shortwave`s ride through the area, with expected snow amounts of 1-2 inches at higher terrain and lower elevation rainfall of around 0.05" through the Columbia Basin, Blue Mountain foothills, and the Grande Ronde Valley. Slightly higher rain amounts of 0.10-0.15" are likely through the Columbia Gorge and the Yakima/Kittitas Valley through the day today. The upper level ridge rebuilds briefly this evening before shifting east as another weak shortwave approaches the area and passes along the Canadian border. This will bring another round of precipitation to our mountain zones as snow levels hover between 6000-6500 feet. These higher elevations are forecast to pick up an inch of additional snowfall, at best. Lower elevations between 2500-5500 feet along the east slopes of the Washington Cascades will likely experience rain amounts of between 0.05-0.25", with trace amounts possible over the Simcoe Highlands and lower elevations of the Columbia Basin, Blue Mountain foothills, and the Yakima/Kittitas Valleys. Ensembles showcase another transient upper level ridge moving across the Pacific Northwest on Saturday ahead of another progressive pattern of shortwaves Sunday and Monday before a stronger upper level ridge sets up over the area Tuesday onward. Ensemble members all highlight another round of widespread precipitation on Sunday as lower elevations of the Columbia Basin and Blue Mountain foothills are expected to see 0.01-0.05" through the day. More uncertainty develops on Monday as only 52% of ensemble members keep precipitation confined to our mountain zones. Snow levels look to decrease to between 5000-5500 feet Sunday and 4000-5000 feet on Monday, but the lack of overall moisture due to the synoptic pattern being more dominated by ridging will lead to snow accumulations of less than an inch both days. Ensembles then align with a substantial upper level ridge building over the Pacific Northwest on Tuesday and lingering through Thursday. The overall meridional pattern of rebuilding upper level ridges and transient shortwave troughs leads to persistent west- southwest flow aloft, which keeps above normal temperatures in the forecast through the weekend and into next week. The only elongated tenure of an upper level ridge coupled with surface high pressure looks to occur midweek next week. This should keep any developing cold pools or inversions to a minimum until then. 75 && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... MVFR or higher conditions to prevail through the period. A band of rain is currently traversing the Columbia Basin this morning, bringing rain impacts to PSC/PDT, with light rain approaching site ALW. Further west, light rain bands in the Columbia Gorge are expected to impact site DLS through the morning. Dry conditions will briefly return, before periodic rain showers impact sites DLS/YKM between 3Z-7Z. Sites DLS/PSC will see reductions in vsby down to 3SM in rain this morning, while VFR conditions are expected to prevail through the remainder of the period at all sites. Winds will be light, 12kts or less, through the period. Lawhorn/82 && .Preliminary Point Temps/PoPs... PDT 38 52 37 51 / 20 10 10 0 ALW 40 52 39 52 / 30 20 20 10 PSC 35 47 34 48 / 30 20 10 0 YKM 35 45 33 47 / 50 30 10 10 HRI 35 48 35 48 / 30 10 10 0 ELN 34 42 33 42 / 70 40 20 10 RDM 35 55 33 57 / 20 10 0 0 LGD 36 48 34 51 / 20 10 10 0 GCD 35 53 35 54 / 20 10 0 0 DLS 38 49 40 51 / 50 40 20 10 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ UPDATE...80 DISCUSSION...75 AVIATION...82