textproduct: Pendleton

KEY MESSAGES

1. Dry and warm conditions through the day today

2. Breezy conditions through the Grande Ronde Valley today

3. Breezy through the wind prone areas Saturday and light showers in the Cascades

DISCUSSION

Current nighttime satellite is showing mostly clear skies over the region. This will allow for cooler overnight temperatures in the upper 30s and low 40s. Warmer temperatures along the foothills of the Blues due to the easterly downslope wind regime causing temperatures to be warmer in the mid to upper 40s with isolated 50s. Temperatures will be in the upper 30s across portions of central OR and the eastern mountains. The Basin, Gorge, foothills and Yakima/Kittitas Valleys will see temperatures in the upper 30s to low 40s.

Not a lot of change for the forecast since last night/ Deterministic models continue to be in firm agreement with the upper level ridge remaining over the area through Friday afternoon. Temperatures will peak today with in office calculations continuing to show temperatures to be nearly 15-20 degrees above seasonal normal. Looking at the ensemble guidance, 90% of the HREF raw ensembles show temperatures to be in the low to mid 70s through the Basin, foothills, Gorge and Yakima/Kittitas Valleys while central OR and the John Day Basin will see upper 70s with some possible 80s mixed in.

Models show that today (Friday) will see the synoptic transition of the upper level ridge moving east and an upper level trough building into the region from British Columbia. As the ridge leaves the region, current runs of the deterministic models show a weak surface level high in Treasure Valley while a weak surface low is over the Columbia Basin. This is the perfect synoptic set up for easterly breezy winds through the Grande Ronde Valley. Easterly winds are currently already flowing over the Blues based off ground observations. Winds through the area will begin to pick after midnight Thursday reaching its peak after 11 AM and persisting through 5 PM Friday. HREF raw ensembles show sustained winds of 20- 25 mph with gusts of 30-35 mph with some isolated 40 mph gusts with above 80% agreement.

Saturday models show the upper level trough beginning to dig into the PacNW. As the leading edge of the trough wedges itself against the Cascades, the pressure gradients begin to tighten leading to breezy conditions through the typical winds prone gap areas. Looking at the NBM raw ensembles, 60-80% are in agreement that the Kittitas Valley will see winds between 20-25 mph sustained winds with gusts of 30-35 mph. The Gorge will see 15-20 mph sustained winds and gusts of 25-30 mph. With this front, light precipitation along the crests of the Cascades is expected with near 0.03 inches in 24 hours and 90% HREF ensemble agreement.

By the beginning of next week models show the upper level trough form into a low pressure system and begin to move to the south. Models show the low to cutoff and move to the south of the region. This will bring chances of wrap around moisture to the Blues and the Wallowa Mountains. Clusters are however struggling to resolve the regime with timing, positioning and strength all varying between the models. The only agreement the models seem to have is the fact there is a low pressure system making its way along the west coast.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

VFR conditions will persist through the forecast period. Winds will be generally light through the period with only RDM seeing winds near 10 kts and gusting to near 18 kts after 15Z. Mostly clear skies will also persist through the period.

Preliminary Point Temps/PoPs

PDT 73 41 69 35 / 0 0 0 0 ALW 74 49 69 40 / 0 0 0 0 PSC 69 37 71 33 / 0 0 0 0 YKM 70 42 69 35 / 0 0 0 0 HRI 70 38 70 34 / 0 0 0 0 ELN 67 39 61 29 / 0 0 0 0 RDM 79 34 66 27 / 0 0 0 0 LGD 71 45 70 35 / 0 0 0 0 GCD 76 37 72 34 / 0 0 0 0 DLS 75 46 69 38 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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