textproduct: Pendleton

AVIATION...18Z TAFs

Mostly VFR conditions forecast through the period. CIGs and vsby will stay VFR through late this evening and early tonight, but an incoming system will bring lowering CIGS of sct to ovc down to around 2kft to 6kft by tomorrow morning at all sites. Precipitation associated with the incoming system will start around 10Z for RDM/BDN, 11Z for DLS, and between 13Z-15Z for sites PDT/YKM/ALW/PSC. Heavier precip at site DLS may reduce vsby to 3 to 5 miles. Breezy winds will continue or redevelop this morning at most sites, with winds weakening this evening and staying less than 12kts through the remainder of the period...except at site BDN where winds 12-17kts with gusts to around 25kts will redevelop around or after 15Z. Lawhorn/82

PREV DISCUSSION

/issued 330 AM PST Sat Dec 6 2025/

DISCUSSION...

Broad overview: The forecast for the next week can be succinctly described as warm, wet, and windy. A subtropical high in the Pacific coupled with a remarkably persistent quasi-zonal to zonal jet stream and multiple frontal systems will direct several rounds of subtropical to tropical moisture into the Pacific Northwest.

Key Messages:

1. Windy to very windy conditions this morning, then breezy to windy this afternoon. Numerous Wind Advisories in effect.

2. Winter Weather Advisory in effect above 4000 feet for the Upper Slopes of the Eastern Washington Cascades Crest through this evening.

3. Breezy to windy conditions return Monday.

4. Ample precipitation through next Wednesday or Thursday combined with high snow levels will lead to rises on area rivers.

Headline updates: No updates to headlines on this shift.

Precipitation is pinned to the Cascades and northern Blues this morning with dry, windy conditions present across the lower elevations. Snow levels are approximately 4500-6000 feet, lowest across the Washington Cascades, but remain just too high for snow at mountain pass levels. While temperatures are anticipated to cool a couple degrees, they are also running a couple degrees warmer than forecast by NBM, HREF, and REFS guidance, so thinking snow totals for the Upper Slopes of the Eastern Washington Cascades Crest will be lower than previously forecast. As such, have adjusted wording in the Winter Weather Advisory to reflect lower snow accumulations.

The main talking point today is the ongoing breezy to very windy westerly (southwesterly to northwesterly depending on the exact location) winds. A persistent 10-12 hPa pressure difference between PDX and GEG and low-level jet of 45-65 kts have both been in place overnight. Winds of 20-40 mph with gusts of 35-55 mph have been observed across a broad swath of the Columbia Plateau, and locally stronger winds have surfaced along exposed ridges. The strongest winds should only last a few more hours as surface pressure gradients and winds aloft gradually slacken, but widespread breezy conditions are anticipated to continue into the afternoon hours.

Lastly, will note a significant amount of precipitation is forecast for the mountain areas Monday through Wednesday or Thursday of next week. While confidence in precise amounts is still low, and will depend on the exact location of the jet stream and incoming frontal systems, the NBM places a 30-50% chance of reaching or exceeding 5 inches of liquid equivalent across the Oregon Cascade crest through the 72-hr period ending 4 AM Thursday, and an even higher 50-75% chance for the Washington Cascades. For the northern Blues, the chance of 3 inches of liquid equivalent is 20-40%. Through the bulk of the next week, snow levels are then forecast to remain high at mostly 5-8 kft with periodic dips to 4.5 kft. With that in mind, much of this precipitation is forecast to fall as rain, and rises on area rivers are anticipated. Current forecasts from the NWRFC in Portland do place multiple rivers at action stage or minor flood stage by the latter half of next week.

PRELIMINARY POINT TEMPS/POPS

PDT 51 39 53 44 / 40 30 90 60 ALW 51 41 52 45 / 50 40 90 70 PSC 56 40 53 44 / 10 20 80 30 YKM 54 35 51 37 / 20 30 90 30 HRI 56 41 54 44 / 20 30 80 50 ELN 48 33 45 35 / 30 30 90 40 RDM 50 33 54 38 / 20 30 50 40 LGD 46 34 43 38 / 70 50 90 90 GCD 46 33 47 39 / 50 40 80 60 DLS 55 45 54 48 / 60 80 100 80

PDT WATCHES/WARNINGS/ADVISORIES

OR...None. WA...Winter Weather Advisory until 7 PM PST this evening for WAZ522.