textproduct: Pendleton

KEY MESSAGES

- Red Flag Warning for critical fire weather conditions in the Oregon Columbia Basin today, with local enhanced fire weather conditions elsewhere.

- Warming temperatures through Tuesday, with isolated thunderstorms in the eastern mountains Sunday through Tuesday.

- Another round of elevated fire weather concerns around midweek.

DISCUSSION

Zonal flow will remain over the region today before the flow becomes southwesterly later Sunday into Monday. The flow will then remain southwesterly though Tuesday before becoming more westerly again on Wednesday.

Dry and diurnally breezy conditions are expected today. The dry conditions coupled with afternoon RH values in the teens in many locations has prompted the issuance of a red flag warning for the Columbia Basin of Oregon. In other areas, winds are not expected to be as high, but RH values will still be low, so elevated fire weather concerns are still expected despite no fire weather headlines.

As the flow becomes more southwesterly on Sunday, a series of short waves will move through the flow each day. As a result there will be low (<20 percent) chances of showers and thunderstorms, mainly over the eastern Oregon mountains, with the best (albeit low) probabilities Monday and Tuesday.

Monday and Tuesday will also see the hottest temperatures, with Monday in the low to mid 90s in the lower elevations and Tuesday in the mid to upper 90s. The Columbia Basin, could certainly make a run at 100 degrees on one or both of those days. HeatRisk is widespread Moderate across the lower elevations on Monday and Tuesday.

By Wednesday, an area of low pressure is expected to move into British Columbia and will bring a weak front through the area. Stronger westerly winds will increase later Tuesday and continue behind the front will bring another period of enhanced fire weather concerns, especially for the Columbia Basin, but also for the Kittitas Calley, Simcoe Highlands and possibly other areas as well. RH values will be higher on Wednesday in some areas, before decreasing again on Thursday.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Latest satellite shows onshore flow and stratus west of the Cascades with largely clear skies in the northwest interior/east of the Cascades. VFR conditions expected to continue through the TAF period at all sites. Main aviation challenge revolves around winds this afternoon with sharpening surface pressure gradient developing today supporting modest breezes and gusts at TAF sites this afternoon-evening, except KDLS with peak gusts today likely exceeding 25 kts (confidence 60- 80%). Winds will then lessen with gusts subsiding by early morning.

FIRE WEATHER

Red flag warning is in effect for this afternoon and evening for OR691 as gust diurnal winds and low RH create critical conditions. For other areas, winds aren't expected to be as strong but will still have low RH so there will still be elevated concerns. Winds will decrease Sunday into Monday.

Elevated fire weather concerns occur again later Tuesday through midweek as westerly winds increase. Will have to see how the RH profile combines with these increasing winds.

There is also a low (<20 percent) chance of thunderstorms Sunday through Tuesday, mainly over the eastern Oregon mountains.

Preliminary Point Temps/PoPs

PDT 89 53 87 56 / 0 0 0 0 ALW 90 58 88 60 / 0 0 0 0 PSC 93 56 91 56 / 0 0 0 0 YKM 92 55 91 58 / 0 0 0 0 HRI 92 56 90 57 / 0 0 0 0 ELN 83 51 87 54 / 0 0 0 0 RDM 88 49 89 54 / 0 0 0 0 LGD 89 53 88 55 / 0 0 0 0 GCD 92 52 93 56 / 0 0 0 10 DLS 87 57 92 60 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...OR...Red Flag Warning from noon today to 10 PM PDT this evening for ORZ691.