textproduct: Pendleton

KEY MESSAGES

- Mountain showers with isolated lower elevation showers develop through the weekend.

- Cooler temperatures with breezy to windy conditions develop Friday, with possible overnight freezing.

- Patchy blowing dust possible Friday across the Columbia Basin.

DISCUSSION

Not much to talk about on radar and satellite with dry and clear conditions prevailing thanks to an upper level ridge aloft. The upper level ridge will continue pushing out of the area, with the upper level pattern becoming more zonal heading into Thursday. We'll see temperatures peak today in the low to upper 80s across the lower elevation areas with the oncoming breakdown of the ridge. A thermal trough will develop through today allowing for drier air to prevail with minimum RH's dropping down to 15 to 25 percent in most areas of the lower elevation (locally lower in parts of Central Oregon).

An approaching weather system will drop down from the Gulf of Alaska Friday (>90% chance) and bring breezy conditions across the Basin, Simcoe Highlands, Cascade gaps, and Kittitas Valley along with mountain showers through the early Sunday morning (30-50% chance). GFS and NAM have slightly trended down on pressure gradients developing with the approaching system with values of 9-12 mb from Portland to Spokane. Currently, NBM advertises 30-50% chances of wind gusts 45 mph or greater Friday for the Simcoe Highlands, Foothills of the Blue Mountains, and the Kittitas Valley. The strongest winds are expected to occur between 2 PM and 8 PM. We might see some elevated fire weather concerns with lingering dry air and breezy to locally windy conditions . Another concern on Friday will be patches of blowing dust with reduced visibility across the Columbia Basin, Columbia Gorge, and the Yakima/Kittitas Valleys.

Frigid and freezing temperatures are anticipated starting Saturday as cold, arctic air funnels into the region from Canada. This will bring high potential for first season freezes across the Columbia Basin, Central Oregon, and other sheltered valleys. Freezing temps will continue to build through the weekend with the ongoing funneling of cold air and bring widespread freezing temperatures across Central Oregon, mountain areas, and parts of the Columbia Basin. NBM currently advertises 20-50% chances of freezing temperatures for Central Oregon and the Foothills of the Blues Saturday morning which jump up 70-80% chance by Monday morning. Chances across the Basin remain tapered down to 20-40% chances by Monday.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

VFR conditions with calm and dry conditions prevail through the forecast period. Winds generally calm with sustained winds mostly less than 12 knots. No CIG or VIS issues expected.

Preliminary Point Temps/PoPs

PDT 80 50 72 39 / 0 0 30 10 ALW 80 57 72 43 / 0 0 30 20 PSC 81 47 75 39 / 0 0 0 0 YKM 81 50 70 38 / 0 0 0 0 HRI 81 50 73 39 / 0 0 0 0 ELN 79 48 63 33 / 0 0 20 0 RDM 84 40 71 29 / 0 0 0 10 LGD 84 45 75 36 / 0 0 10 50 GCD 87 46 77 37 / 0 0 0 40 DLS 85 52 71 42 / 0 0 10 0

PDT WATCHES/WARNINGS/ADVISORIES

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