textproduct: Pendleton

KEY MESSAGES

- Breezy to locally windy through the Cascade gaps and across much of the Columbia Plateau this afternoon and evening.

- Cooler, near-normal temperatures Sunday into next week in the wake of today's cold frontal passage.

- Mostly dry conditions continue into next week. Low (20-40%) chance of precipitation across the Blue Mountains by late Wednesday, expanding to cover the Cascade and Blue Mountains Thursday through the remainder of the week.

DISCUSSION

Satellite shows a weak cold front passing from west to east across the forecast area this afternoon. Breezy to locally windy westerly winds will persist through the Cascade gaps and across much of the Columbia Plateau through evening (95% confidence), with lighter winds returning this evening and tonight in the wake of the front.

Cool overnight lows ranging from the lower 30s to lower 40s are forecast tonight, locally near or slightly below freezing for cold-prone locations of the Columbia Basin and surrounding lowlands, but confidence in widespread freezing temperatures was too low (40% or less) to issue any freeze headlines.

Dry zonal to quasi-zonal flow aloft is forecast over the Pacific Northwest on Sunday. Upwind in the Pacific, ensemble NWP guidance is in excellent agreement (99% confidence) that a closed low will develop offshore and track towards the Pacific Northwest. While some differences in the exact track and depth of the low are present among clusters of ensemble solutions, they all indicate it will dive southeast towards the OR/CA border by Monday, with very low (10% or lower) chances of precipitation across the central Oregon region.

The low will likely continue to track south off the California coast Tuesday through Wednesday (90% confidence). Weak shortwave energy may facilitate precipitation across the Blue Mountains region by Wednesday night (20-40% PoPs), but the main low is expected (90% confidence) to remain well south of our region. Low-medium (20-60%) PoPs then continue Thursday through the remainder of the week as the upper low tracks inland across California and the Great Basin, and shortwave energy from the Pacific may track into the region (50-80% confidence).

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

VFR conditions to persist for all sites except KBDN and KRDM having low cloud bases below 3000 resulting in MVFR conditions form 6z to 17z. All sites have increasing cloud cover towards the evening into the overnight with lowering cloud bases. KDLS has gusts of 25KT and will last through 2z. Calmer conditions and higher cloud bases appear towards the end of the TAF period.

Preliminary Point Temps/PoPs

PDT 35 63 36 62 / 0 0 0 0 ALW 40 64 42 62 / 0 0 0 0 PSC 36 66 37 64 / 0 0 0 0 YKM 36 64 39 64 / 0 0 0 0 HRI 38 65 37 64 / 0 0 0 0 ELN 31 61 35 61 / 0 0 0 0 RDM 30 63 29 59 / 0 0 0 0 LGD 36 68 40 68 / 0 0 0 0 GCD 36 72 39 70 / 0 0 0 0 DLS 40 68 44 66 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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