textproduct: Pendleton

KEY MESSAGES

- Windy conditions this afternoon across the Columbia Gorge and the foothills.

- Showers and isolated thunderstorms this afternoon across the Eastern Mountains.

- Gusty winds potentially approaching wind advisory criteria on Friday with widespread showers.

DISCUSSION

Quiet weather earlier today is starting to turn more active with showers starting to develop across the Blue Mountains. Current satellite depicts partly cloudy skies across much of the region this afternoon with cumulus and a few towering cumulus developing across the Wallowa and Blue Mountains. Latest radar imagery shows that a few showers have developed over the John Day Highlands stretching into the Blue Mountains. As additional destabilization occurs this afternoon, with latest model guidance suggesting around 200-400 MUCAPE developing this afternoon, an isolated thunderstorm may develop (10-20% chance) across the Blue and Wallowa Mountains.

Of additional note this afternoon, windier conditions are starting to develop in areas with channeling effects (ie the foothills, Columbia River Gorge, and the Kittitas Valley). Latest observations depict winds are currently around 15-20 mph with gusts around 20-30 mph. Latest model guidance suggests that these winds remain around 20-25 mph with gusts up to around 35 mph in the aforementioned areas this afternoon. In addition, models suggest RH values will be between 20-30% this afternoon in lower elevations.

Looking past this afternoon, LREF clusters are in relatively good agreement about the upper-air pattern through Saturday as a negatively tilted trough moves through the region on Friday. This system will bring widespread showers to the area with the NBM and LREF clusters suggesting around a 70-90% chance of seeing at least measurable rain (>0.01 in) Friday across the region. The best chances for higher rain totals look to be in the Cascade Mountains. Model guidance is also highlighting the potential for gusty westerly winds Friday afternoon through the Cascade Gaps and the foothills with winds of 15-30 mph and gusts of 35-50 mph (Confidence 70-80%). Additionally, the LREF and NBM suggest around a 25-45% chance of wind gusts meeting wind advisory criteria (wind gusts >45 mph). Probabilities of wind gusts meeting wind advisory criteria have been increasing with model runs yesterday suggesting a lower 10-20% chance.

After Friday, model spread increases substantially but are in general agreement about second trough approaching the PacNW late in the weekend but there is a lot of uncertainty regarding timing and potential impacts. But there is relatively agreement on below average temperatures this weekend (50-60%). Garty/26

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

No risk of ceilings or visibility restrictions for local terminals over the TAF period. DLS will remain the most windy/gusty over the next few hours before a significant decrease in the winds is noticed after sunset. YKM could see a brief uptick in winds during the evening and all other terminals are expected to remain below 12 knots.

Preliminary Point Temps/PoPs

PDT 45 74 46 77 / 0 0 0 0 ALW 51 75 52 78 / 0 0 0 0 PSC 49 77 48 78 / 0 0 0 0 YKM 48 74 49 74 / 0 0 0 0 HRI 49 77 48 78 / 0 0 0 0 ELN 44 69 44 69 / 0 0 0 0 RDM 38 74 40 80 / 0 0 0 0 LGD 44 77 47 85 / 0 0 0 0 GCD 44 80 48 87 / 0 0 0 0 DLS 50 77 52 78 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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