textproduct: Pendleton

AVIATION

MVFR to IFR impacts will persist for the terminals through this entire TAF period. A blanket of stratus in the 1500 to 2000 ft range persists with a stagnant enough pattern as to preclude enough warming or mixing to see significant improvement. Lowest visibility and ceilings in the LIFR or VLIFR categories are be expected this morning at BDN and RDM with only marginal improvement possible later in the day, and high confidence in the return of these conditions (80%) overnight and early Friday.

PREV DISCUSSION

/issued 248 AM PST Thu Jan 22 2026/

DISCUSSION...The forecast area continues to grapple with a stubborn layer of low clouds. Based on overnight satellite imagery, this stratus deck appears to be afflicting essentially the entirety of the forecast area under 4200 feet in elevation. Patchy fog persists in pockets of north central Oregon along US97 and 197, as well as the Wallowa Valley, the latter of which is under a Freezing Fog Advisory until 10 AM Thursday. Hope still persists that an upper- level wave on Friday will eat away at least some of this cloud deck, but the fear is that we won't truly scour out this gloom until a more organized system arrives, which may not be until next week.

Given how much the NBM has struggled as of late in depicting this persistent low cloud deck, took a much more proactive approach to the forecast compared to recent days. For temperatures, opted for a persistence forecast while still allowing for a downward trend in temperatures through Saturday, as the synoptic pattern continues to favor weak NW flow aloft - enough to invite cold air advection, but still too weak to mix out the inversion. For sky cover, outlined the forecast area under 4200 feet in elevation (which roughly matches what satellite imagery depicts) and set it to overcast through Friday morning, while allowing for some retreat of low clouds in central Oregon where the clouds are more transient. And for fog, outlined primarily central and north central Oregon, as well as the John Day and Wallowa Valleys for persistent, patchy freezing fog. Observations and webcams outline these areas for fog coverage in particular.

If I alluded to this low cloud deck potentially sticking around until next week, why did I limit myself to overcast/persistent conditions until Friday? That aforementioned upper-level wave on Friday is one such source of uncertainty. Models generally agree that this system will cause at least a slight uptick in winds across the forecast area, certainly enough to clean out low clouds across central Oregon, as well as the Grande Ronde and John Day Valleys. This is also the most defined synoptic system we've seen in well over a week, so I wanted to hedge myself at least a little bit if this system turns out to more aggressively mix out the inversion than anticipated. It is of the opinion of this forecaster that it is more likely than not (confidence 50-60%) that low clouds will at the very least persist in the Basin and adjacent valleys through the next week, but again, forecast uncertainty is enough that some hedging in the forecast is warranted, I believe.

Ensembles generally point toward the synoptic pattern becoming more progressive over the weekend, rather than the persistent ridging and weak NW flow we've seen over the past week, but an organized wave doesn't look likely until perhaps the end of next week. And even then, plenty of ensemble solutions depict a ridge building back in over the PacNW around the same time. Could be a while before some of us see the sun again, especially in the Basin. 74

AVIATION...12z TAFs...Variable conditions currently across all sites, with MVFR at KDLS/KPDT/KYKM/KALW/KPSC and LIFR at KRDM/KBDN due to reduced ceilings of 300-400 feet. These conditions are expected persist, with dropping ceilings at KPDT/KALW leading to IFR ceilings of 800-900 feet this morning. Elsewhere, conditions will stay constant through the morning before improving to MVFR briefly for all terminals through the afternoon, with the exception of KRDM/KBDN only improving to IFR due to ceilings staying below 1kft. Upper level ridging and surface high pressure extends through the period, keeping conditions dry and winds light (below 10 kts). 75

PRELIMINARY POINT TEMPS/POPS

PDT 32 22 33 19 / 0 0 0 0 ALW 32 24 34 22 / 0 0 0 0 PSC 34 25 40 20 / 0 0 0 0 YKM 34 23 37 19 / 0 0 0 0 HRI 36 24 36 19 / 0 0 0 0 ELN 32 20 34 17 / 0 0 0 0 RDM 29 19 33 13 / 0 0 0 0 LGD 33 21 35 16 / 0 0 0 0 GCD 31 20 36 16 / 0 0 0 0 DLS 38 27 39 23 / 0 10 10 0

PDT WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None.