textproduct: Pendleton

KEY MESSAGES

1. Temperatures today and Wednesday will remain above seasonal normal through Wednesday.

2. An upper level low approaching the region will bring increased winds today increasing fire weather concerns.

3. Continued southwest flow with breezy conditions through the remainder of the week into the weekend.

DISCUSSION

Current satellite shows mostly clear skies with a few lingering clouds. Conditions will remain dry and warm through the day today with increasing cloud cover later in the afternoon and evening.

Models show the ridge of high pressure remaining over the region today ahead of the next system. Looking at in house calculations, temperatures are expected to be near 15 degrees above seasonal normal today. Looking at HeatRisk probabilities, today will be the peak with 80-90% probabilities of areas reaching Moderate HeatRisk (level 2 of 4) across the Columbia Basin. There is also a low to medium risk of areas in the Columbia Basin seeing Major HeatRisk (level 3 of 4) with 30-50% probabilities. Moderate HeatRisk affects those who are sensitive to heat, especially those without cooling/hydration, while Major HeatRisk affects anyone without cooling/hydration.

Models today show the leading edge of the upper level low beginning to make its way onshore. As the low begins to traverse east, the leading edge over the Cascades Wednesday will bring a tightening of the surface pressure gradients. Winds will be increased through the Columbia River Gorge, Kittitas Valley and along portion of the Simcoe Highlands and foothills of the southern Blues. NBM raw ensembles shows 80-90% probabilities that winds will be 15-20 with some isolated 25 mph sustained winds with gusts to near 30-35 mph. The increase in the winds will also raise some fire weather concerns Today. With that, a special weather statement has been issued for isolated areas within the aforementioned places for critical fire weather between 1100-2000 (8PM) Wednesday due to winds and low relative humidity. While not widespread, this will affect a few of the fires already on the landscape as well as any new fire that may occur in these areas.

Looking into the longer term using deterministic models shows the upper level low to move off towards the north and a trough to remain over the region through the weekend. This will bring continued southwest flow across the region with daily breezy conditions through the gaps. Clusters are also in decent agreement over the weekend with the main variance being the amplitude of the trough. Regardless of this, conditions will remain dry and breezy with cooler temperatures and higher humidities through mid-week onwards.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

VFR category is expected through this TAF period for all terminals. Light westerly winds continue overnight with the exception of DLS where breezy winds continue gusting 25 knots at times. Boundary layer mixing on Thursday will bring 20 to 25 kt gusts to YKM/PDT/PSC, mainly after 20z.

FIRE WEATHER

Breezy conditions through the Kittitas Valley, Columbia River Gorge, Simcoe Highlands and foothills of the Blues coupled with low relative humidity will keep the areas under elevated fire weather concerns through the day today. Isolated areas within theses mentioned locations will see critical conditions. While this is not a widespread event, with the fire on the landscape and any new fire that may occur, an special weather statement has been issued between 1100-2000 (8PM) today. As we move on to tomorrow (Thursday), winds will remain elevated. However, due to the upper level system, temperatures will decrease and relative humidity will increase out of critical numbers.

Preliminary Point Temps/PoPs

PDT 56 82 46 80 / 0 0 0 0 ALW 63 85 53 82 / 0 0 0 0 PSC 63 88 50 85 / 0 0 0 0 YKM 61 86 54 84 / 0 0 0 0 HRI 63 85 52 84 / 0 0 0 0 ELN 55 77 48 76 / 0 0 0 0 RDM 50 82 40 81 / 0 0 0 0 LGD 56 88 48 85 / 0 0 0 0 GCD 56 91 51 87 / 0 0 0 0 DLS 63 80 56 81 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Air Quality Alert until noon PDT Friday for WAZ026-522-523. OR...Air Quality Alert until noon PDT Friday for ORZ041-505-506- 509>511.