textproduct: Pendleton

KEY MESSAGES

- Moderate HeatRisk conditions continue through Wednesday thanks to an overhead ridge.

- Breezy winds developing Thursday with lingering dry air will bring elevated/critical fire weather conditions.

- Wetter pattern by the later part of the week with widespread showers region wide with isolated thunderstorms developing across the Blues/Eastern Mountains.

DISCUSSION

Satellite and radar imagery continue to show dry and clear conditions thanks to overhead ridge situated over the Pacific Northwest. Guidance is in great agreement that the ridge will continue to advance through the region, promoting the warming trend to continue through at least Wednesday (70-90% chance). High temperatures will continue to climb into the low to high 90s in the lower elevated areas with dry air continue to linger in the region. HeatRisk will continue to show widespread moderate risk through Wednesday, mainly confided to the lower elevations that include the Columbia Basin, Eastern Gorge of WA & OR, Kittitas/Yakima Valley, and Central OR.

By Thursday, the upper level ridge will continue to move east and a mid-level shortwave will slide into the region promoting breezy winds of 20-30 mph gusts to develop. With breezy winds and dry air still lingering despite the shortwave approaching, elevated fire weather conditions will develop across the Oregon Columbia Basin (OR691) (70-80% confidence), as well as across Kittitas/Yakima Valley Region (WA690), Columbia Basin of Washington (WA691), and Central Oregon (OR700) (70-80% confidence).

With the passing shortwave, a trough will move into the region by Friday (60-80% confidence) bringing unsettled weather across the region that include breezy winds, widespread rain showers, and isolated thunderstorms across the mountain regions (15-30% chance for the thunderstorms). Temperatures will have a significant cooling trend with the passage of the cold front, dropping high temperatures to the mid to high 70s across the lower elevation (60-80% confidence). The good news on the fire weather side, is that the sufficient moisture transportation will relief us of the dry air. Current NBM guidance advertises minimum relative humidities jumping from the 10-20% range up to 30-50% with overnight recoveries improving to the 'good' to 'excellent' range by late Thursday night/early Friday morning (70-90% confidence).

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

VFR conditions will persist through the period with light winds less than 12 knots for all TAF sites until 22-23Z. After 22-23Z, RDM/BDN will see an increase in winds of 10-13G17-21KT before settling to 10kts after 01-04Z respectively. No CIG or VIS issues expected.

Preliminary Point Temps/PoPs

PDT 91 56 92 59 / 0 0 0 0 ALW 92 61 93 64 / 0 0 0 0 PSC 94 59 96 61 / 0 0 0 0 YKM 92 61 95 59 / 0 0 10 0 HRI 93 58 95 63 / 0 0 0 0 ELN 89 60 91 59 / 0 0 20 10 RDM 89 52 88 48 / 0 0 10 10 LGD 90 54 89 54 / 0 10 0 0 GCD 94 52 91 52 / 0 0 10 10 DLS 95 64 94 62 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Heat Advisory until 11 PM PDT this evening for WAZ024. OR...Heat Advisory until 11 PM PDT this evening for ORZ041. Red Flag Warning until 8 PM PDT this evening for ORZ691.