textproduct: Pendleton

DISCUSSION

A ridge situated over the PacNW will flatten today in response to a series of upper-level waves passing to our northwest. These waves will bring precip to the central WA Cascades over the next couple of days, but with snow levels rising to above 5000 ft by midday Sunday due to W/SW flow aloft, not expecting any snow impacts to our main mountain passes in the area. The region will otherwise be entering a benign pattern over the next week, as high pressure returns Tuesday into Wednesday.

Not much to speak of this afternoon as latest satellite imagery depicts mid-level clouds pouring into the forecast area as a result of the aforementioned W/SW flow. Showers remain situated over the Olympic Peninsula, but are expected to shift west-northwestward over the next 24 hours, clipping the central WA Cascades with precip. Again, outside of mountaintops, snowfall impacts to the area are expected to be minimal, with little to no snow occurring across Snoqualmie, Blewett, or White Passes. Otherwise, only impacts today are breezy winds across the Grande Ronde Valley stemming from this ridge flattening, and some locally dense freezing fog in the Kittitas Valley this morning due to relatively stagnant conditions there.

High pressure rebuilds by the midweek, however models disagree as to where this ridge centers itself through the end of the work week. Deterministic guidance suggests we'll see another flattening of this ridge late Wednesday into Thursday, before rebuilding offshore heading into next weekend. Little signal for precip currently exists across ensemble guidance as of now, so main impacts from this pattern would be a slight rebounding of temps, before fog develops across the Basin midweek due to the strengthening temperature inversion over time. 74

AVIATION...00z TAFs

High pressure continues to dominate the region, leading to light winds. VFR flight categories are of high confidence for all the the terminals (90%) for the duration of the period. There is a low confidence (maybe 10%) that IFR stratus (500 to 1000 ft ceilings) can return around KDLS at any time overnight or early in the day Sunday. Russell/71

PRELIMINARY POINT TEMPS/POPS

PDT 30 52 34 55 / 0 0 0 0 ALW 34 50 37 55 / 0 10 0 10 PSC 29 49 33 54 / 0 10 0 0 YKM 30 44 33 50 / 0 20 10 10 HRI 30 47 32 53 / 0 10 0 0 ELN 29 41 32 48 / 10 30 30 30 RDM 26 52 28 54 / 0 0 0 0 LGD 30 44 31 48 / 0 0 0 0 GCD 28 48 30 53 / 0 0 0 0 DLS 35 49 36 51 / 0 10 10 10

PDT WATCHES/WARNINGS/ADVISORIES

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