Heppner, OR Weather

.Updated Aviation Discussion.

Key messages

- Near- to below-normal temperatures through the weekend.

- Periodic showers through the week, then medium-high (40-80%) chance of precipitation for central/eastern Oregon and southeast Washington over the weekend.

Discussion

Satellite imagery shows a broad low-pressure system located just west of Vancouver Island. This low is responsible for isolated showers across the forecast area, which radar reveals are predominantly confined to the mountains (especially the Cascades). Aside from some patchy dense fog in valley locations this morning, there is little else to note.

Ensemble NWP guidance is in excellent agreement that the aforementioned upper-level low will continue to churn offshore through the week, and produce low-medium (5-40%) chances of showers, mainly over the mountains and highest along the Cascade crest.

Over the weekend, the low is expected (90% confidence) to move inland. Chances of precipitation are medium-high (40-80%) across the majority of central/eastern Oregon and southeast Washington Saturday afternoon through Sunday morning. The best chance of significant precipitation will be over the northeast Blue Mountains where the NBM places a 30-60% chance of 0.25" and 10-40% chance of 0.50" of QPF.

Ensemble spread grows Sunday into Monday with regard to how quickly the low will exit to the east and upper-level ridging will build in from the Pacific. Regardless, dry conditions are forecast to return Monday, and this presents the best chance (75% or less) of a season-ending freeze for remaining eligible forecast zones.

Uncertainty in the 500-hPa pattern then grows Tuesday through the remainder of the week. Mostly dry conditions are forecast to continue until Thursday when ensemble guidance hints at the return of some more active weather.

Aviation

VFR conditions currently across most sites, with KDLS experiencing IFR conditions due to reduced ceilings of 600 feet. These ceilings should lift to MVFR around noon before VFR conditions occur during the afternoon. Winds will stay light and below 10kts at all terminals. Ceilings are forecast to drop back down to 2.5kft overnight tonight for KDLS, returning MVFR conditions through Friday morning. 75

.Preliminary Point Temps/PoPs: PDT 54 32 49 30 / 0 0 0 10 ALW 55 35 50 34 / 0 0 0 10 PSC 55 31 54 29 / 0 0 0 0 YKM 52 32 53 28 / 0 10 30 0 HRI 56 31 52 28 / 0 0 0 0 ELN 48 24 48 22 / 0 10 40 0 RDM 53 23 50 20 / 0 0 0 0 LGD 57 31 58 30 / 0 0 0 10 GCD 58 32 57 32 / 0 0 0 0 DLS 54 36 55 32 / 0 20 20 0

Watches, warnings and advisories

WA: Dense Fog Advisory until noon PDT today for WAZ026. OR: None.