textproduct: Pendleton

KEY MESSAGES

- Lingering showers and isolated thunderstorms through the morning hours over eastern areas.

- Breezy conditions through Saturday, especially for the Columbia Basin, Gorge, Kittitas Valley, Simcoe Highlands.

- Temperatures will be a bit cooler today and Saturday then will rise Sunday into next week and widespread Moderate HeatRisk returns as well with some 30 to 50 percent probabilities of Major HeatRisk in the Basin and Yakima Valleys by midweek.

DISCUSSION

Latest radar showed isolated showers and a few thunderstorms mainly from Tri-Cities eastward early this morning. These developed in some lingering instability. Guidance suggests these showers and thunderstorms should hang around through the morning before dissipating.

The upper low off the Washington coast continues to move northward. By late afternoon, it should move into British Columbia. As the low moves further into British Columbia and eventually further east around the periphery of high pressure, its associated trough will weaken and be absorbed into the large flow. This will permit the strong ridge over the Rockies to move westward.

As this happens early next week, temperatures are expected to rise. Exactly how hot we get is still a bit in question but both the GFS and ECMWF ensembles put the Columbia Basin at or above 105 degrees Tuesday through Thursday, and at least 10 percent of the members are 110 degrees. Widespread Moderate HeatRisk will return and the potential for Major HeatRisk, especially across the Columbia Basin reaches 30 to 50 percent, and could end up being higher. Ultimately, the position of the high and smoke from any wildfires will play into the equation as well.

Winds will be a bit breezy, especially across the Gorge, Basin, Kittitas Valley and Simcoe Highlands through Saturday, then should decrease as the high builds in. RH values will be in the teens through Saturday, but wind gusts should be in the 20 to 30 mph range. Elevated fire weather conditions can be expected, but the wind criteria will have to be watched, but looks to be just shy of what is needed for any headlines.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

VFR conditions are expected at most TAF sites through the period. The only possible exceptions are PDT and ALW where smoke from wildfires brought in on southwesterly winds reduced VSBYS at PDT and CIGS and VSBYS at ALW. Oftentimes, this is very directionally dependent and yesterday it was more southwest to west and today's wind looks to be more northwest at PDT and southwest to west at ALW. For now, have decided to include some VSBY restrictions at both locations.

Winds will gust to around 25 kts at DLS and 15 to 20 kts at PDT, RDM and BDN, before decreasing later this evening. All other sites will be 10 kts or less.

Preliminary Point Temps/PoPs

PDT 90 57 91 56 / 0 0 0 0 ALW 93 63 93 62 / 0 0 0 0 PSC 95 61 95 59 / 0 0 0 0 YKM 94 58 94 59 / 0 0 0 0 HRI 93 61 94 61 / 0 0 0 0 ELN 88 56 86 57 / 0 0 0 0 RDM 89 50 91 52 / 0 0 0 0 LGD 94 57 93 56 / 0 0 0 0 GCD 96 54 95 55 / 0 0 0 0 DLS 87 60 90 61 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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