Zillah, WA 98936 Weather

.Updated Aviation Discussion.

Key messages

- Intermittent light mountain snow/rain through the weekend

- Breezy south to southwest winds diminishing this evening

- Below normal temperatures through the week

Discussion

Satellite showed cumulus over large sections of the forecast area This Afternoon with radar returns indicating at least intermittent showers and virga across the Columbia Basin. North Central Oregon and the Gaps. The most concentrated area of radar returns and cloud cover remained across the Cascade Crest and Eastern Slopes of the Washington Cascades. Wind gusts as high as 43 mph with locally sustained winds at 30 mph were seen at the PSC airport. Elsewhere, gusts of 25 to 35 mph area were more of a common range. Breezy to windy/gusty conditions across the Columbia Basin and the foothills of the Blue Mountains, will gradually diminish late this afternoon and evening as the HRRR is showing 30 to 35 mph gusts across these zones early this afternoon weakening to around 20 mph by 5 pm. Locally gusty winds can persist in the area of the horse heaven hills southwest of the Tri-Cities.

A winter weather advisory for snow accumulations remains in effect for the upper slopes of the Washington Cascades This afternoon through 5 pm. Here the HREF 50th percentile takes the snow accumulations up only about 1 more inch in the late afternoon and upwards of 2 more inches on the 75th percentile. At this time, the advisory will not be extended in time. HRRR fields show a steady drop in the snow accumulations though the evening hours.

Continuously cooler than average temperatures are anticipated through the week as cyclonic flow aloft maintains cooler mid level air and clouds alongside occasional mountain showers. The next better chances for accumulating mountain snows comes Thursday Night and into Friday morning as the EC/GFS shows the upper low off the WA coast pivoting southward enough to develop more of a diffluent flow aloft over the region, and NBM amounts to very little snow, less than an inch in comparison this Today's episode. Subfreezing overnight temperatures continue to point areas that have not seen a true growing season ending freeze, and as is typical is the Columbia River Gorge again is last. Friday night/Saturday morning's probabilistic low temperatures near and around The Dalles isnt convincing of a freeze, as high probabilities/chances exist for lows below 36 degrees (80 percent or more), but for 32F or colder, its roughly less than 5 to 20 percent chances across the entire zone. Cloud cover will be a primary contributing factor for any freeze watches and warnings (or not) going forward.

Aviation

VFR conditions currently across all sites, which will stay the course through the period. Light, brief showers will still be possible for KDLS over next hour. Winds will continue to subside for all sites, staying below 12kts through Thursday afternoon. 75

.Preliminary Point Temps/PoPs: PDT 33 52 32 50 / 10 0 0 0 ALW 36 54 35 49 / 20 0 0 0 PSC 30 54 31 53 / 0 0 0 10 YKM 27 52 31 52 / 0 0 30 30 HRI 31 52 31 51 / 0 0 0 0 ELN 22 46 23 47 / 10 0 20 40 RDM 21 51 21 50 / 10 0 0 0 LGD 29 56 30 57 / 30 0 0 0 GCD 28 57 31 55 / 10 0 0 0 DLS 33 54 34 54 / 30 0 20 10

Watches, warnings and advisories

WA: Winter Weather Advisory until 5 PM PDT this afternoon for WAZ522. OR: None.