Milton-Freewater, OR 97862 Weather

.Updated Aviation Discussion.

Key messages

- Near- to below-normal temperatures into next week.

- Medium- high (30-70%) chance of precipitation for central/eastern Oregon and southeast Washington over the weekend.

- Low chance (30% or less, except for freeze-prone areas) of a season-ending freeze for the eastern Columbia River Gorge Saturday and Monday.

Discussion

Initially, the risk for limited visibility in fog continues locally over the Dead Mans pass in the Blue Mt Foothills area which has been expanding locally through the afternoon. Light winds converging in the area per mesonet obs leaves little to gain in confidence on the duration of this local fog. HRRR model suggests a broader shift form west to easterly winds after 01z. For Tonight, the cloud cover associated with the lingering upper low off the PAC NW coast is shown as clear to few based on satellite imagery over the eastern Columbia River Gorge. That area of clearing begins to fill back in with high and mid level clouds by the middle of the overnight, damping the probabilities for freezing temps at DLS. LAMP guidance now forecasting the upper 30s at The Dalles for Saturday morning.

The upper low that has hung off the PacNW coast for several days will finally move inland as a deeper trough, moving into the Interior NW by Sunday morning. This will begin a pattern of increased rain chances for the central Oregon forecast zones by Saturday morning. Chances for showers will spread cross the southern mountains on Saturday and into the eastern mountains by Saturday night. Saturday night though Sunday morning will being the highest 6-hr precipitation/QPF window with mean NBM amounts bringing a few hundredths of an inch to around 0.15. Higher NBM QPF around a quarter of an inch is along the Eagle Caps. Potential for higher amounts of precipitation exists, with the 75th percentile NBM bringing a 48 hours basis of about one quarter of an inch over much of the the Northern Blue Mountains of Oregon, and the Northern Blue mountains Foothills and up to 0.60 of liquid equivalent to the the Eagle Caps/Wallowa county. Additionally, snow levels above generally 5000 ft will allow for a mix of rain/snow p-type above this level. NBM forecast about 1 to 3 inches of snow along the Eagle Caps.

Behind the exiting trough/low is a short duration ridge sliding across the region on Monday which will result in dry conditions areawide and a bump in pressure gradient driven southerly surface winds across the Grande Ronde Valley. This moderately breezy setup for the Grande Ronde valley, as the 50th to 90th percentile suggest 20 to 25 knots sustained winds, which is approaching a wind advisory criteria (30 mph sustained) .

Aviation

Varied conditions currently across sites, with VFR at KPSC/KDLS/KBDN/KYKM, MVFR at KPDT/KALW. These ceilings are expected to lift slightly through the afternoon and early evening. Winds will stay light and below 10kts for all sites through the period. Fog is expected to return for KPDT overnight tonight, dropping visibilities to around 1/2SM. 75

.Preliminary Point Temps/PoPs: PDT 33 50 34 51 / 0 0 40 50 ALW 36 51 37 49 / 0 10 50 50 PSC 31 54 34 56 / 0 0 20 20 YKM 31 54 33 59 / 0 0 10 10 HRI 31 51 33 54 / 0 0 30 30 ELN 23 50 27 55 / 0 0 10 0 RDM 24 48 26 49 / 0 10 40 0 LGD 32 57 36 49 / 0 30 60 60 GCD 34 57 36 47 / 0 10 40 50 DLS 34 55 36 59 / 0 0 30 0

Watches, warnings and advisories

WA: None. OR: None.