textproduct: Pendleton

KEY MESSAGES

- Southwest flow through Monday will bring shower and isolated thunderstorm chances mainly to far eastern Oregon.

- Increased Gap wind potential Monday night into Tuesday.

- Another chances of showers and thunderstorms toward the weekend.

DISCUSSION

Southwest flow will continue through Monday. Several short waves will move through the flow. These short waves coupled with residual moisture could trigger showers and isolated afternoon thunderstorms, mainly for Wallowa County, but other mountain areas can't be ruled out.

By Tuesday, the Pacific Northwest gets into more of a split flow pattern and as a result, west winds will increase across the area. Winds will become gusty beginning MOnday night and into Tuesday, with wind gusts 20 to 30 mph, with some locations possibly as high as 35 mph, in the usually breezier areas such as the Kittitas Valley, Simcoe Highlands, Blue Mountain Foothills, Columbia Basin and Gorge. NBM probabilities of wind gusts >=25 mph are >60 percent, while NBM probabilities of wind gusts >= 39 mph are generally 50 percent or less.

RH values do decrease a bit between Monday and Tuesday and with the gusty winds, fire weather conditions will be elevated, and could become critical. Tuesday will have to be monitored for any fire weather headlines.

Beyond Tuesday, the midweek period look rater quiet, in dry west to southwest flow.

However, by the weekend an area of low pressure will move northward off the coast. This low is then expected to move onshore in Oregon or Washington at some point on Saturday. There is still some disagreement as to where the low comes ashore and how strong it will be and the natural uncertainty in a forecast 5 days out, but shower and thunderstorm chances do look to increase, especially for the mountains as we head into the weekend.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

VFR conditions to prevail through the period. Low confidence (20%) in any smoke impacts redeveloping at sites, though if impacts do occur expect reduction in vsby in the overnight and early morning hours. Winds will be around 15kts with gusts up to 25kts at sites DLS through this evening. Otherwise, winds will be light at all sites through the period. Lawhorn/82

FIRE WEATHER

Isolated showers and thunderstorms (20-25% today) and (<20% Monday) are possible mainly across Wallowa County in southwest flow.

As the flow becomes more westerly Monday night into Tuesday, winds will increase and become gusty, with gusts as high as 20 to 30 mph and possibly as high as 35 mph across the Kittitas Valley, Simcoe Highlands, Blue Mountain Foothills and the Columbia Basin and Gorge. These winds and low relative humidities will yield elevated fire weather conditions Tuesday and could bring critical conditions once again.

Beyond that, there is the potential for more thunderstorms going into next weekend.

Preliminary Point Temps/PoPs

PDT 57 88 58 89 / 0 0 0 0 ALW 63 90 64 90 / 0 0 0 0 PSC 59 93 60 94 / 0 0 0 0 YKM 60 93 62 93 / 0 0 0 0 HRI 61 92 63 92 / 0 0 0 0 ELN 58 89 60 86 / 0 0 0 0 RDM 51 87 49 89 / 0 0 10 0 LGD 57 91 57 90 / 0 10 20 0 GCD 56 91 56 91 / 0 0 10 0 DLS 60 92 63 89 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Air Quality Alert until noon PDT Monday for WAZ026-522-523. OR...Air Quality Alert until noon PDT Monday for ORZ041-503-505-506- 508>511.