textproduct: Pendleton

KEY MESSAGES

- Unseasonably warm temperatures through Friday

- Cooler, more normal temperatures beyond Friday

- Continued rain over the Washington Cascades will keep rivers running high.

DISCUSSION

A large area of high pressure over the southwest will continue to build northward through Friday. The building ridge will bring mainly dry weather and temperatures that are 15 to 20 degrees above normal to the Pacific Northwest through Friday. The only exception will be for the Washington Cascades, which will be on the north side of the ridge, which will continue to receive rain.

By later Friday into Saturday, the ridge is pushed eastward, a cold front crosses the region and the flow becomes more westerly and zonal. This will allow for a return to cooler, more normal temperatures. With the drier westerly flow, the Cascades look to dry out through at least Tuesday.

Rainfall amounts over Washington Cascades still look to be close to 2 inches along the crest, with lesser amount elsewhere. QPF did come down a bit with this run. Amounts on the Oregon Cascades and Blue Mountains are generally 0.25 inches or less. The amounts across the Washington Cascades, along with the much warmer temperatures causing snow melt will contribute to high rivers. Some rivers, mainly the Naches and and Yakima will have points that approach or exceed flood stage.

High temperatures in the lower elevations and central Oregon will be in the lower to mid 70s through Friday and could approach 80 degrees in central Oregon. These values would be 15 to 20 degrees above normal, and would be close to records in many areas. Overnight lows will mainly be in the 40s, but may not drop below 50 in the Columbia Basin and along the foothills of the Blue Mountains.

The ECMWF EFI shows widespread values of 1.00 for high temperatures across eastern and central Oregon and 0.8 to 0.9 across southeastern Washington. For lows, values generally range from 0.8 to 0.95. NBM probabilities of high temperatures >= 80 degrees are around 90 percent in central Oregon and 30 to 40 percent in the Columbia Basin and foothills of the Blue Mountains.

Additionally, there will be some diurnally breezy winds today, Thursday, and especially Friday as the cold front moves through. Winds will be strongest in the Simcoe Highlands and Cascade gaps as well as the Columbia Basin. Wind gusts will mainly be in the 20 to 30 mph range today and Thursday, though possibly a bit higher in the Simcoe Highlands and 25 to 35 mph range on Friday.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

VFR conditions are expected. Winds will mainly be less than 10 kts. However there could be some gusty winds at BDN, RDM and PSC that will increase winds to the 10 to 15 kt range and possibly as high as 20 kt range mainly this afternoon.

Preliminary Point Temps/PoPs

PDT 73 47 73 50 / 0 0 0 0 ALW 72 52 72 53 / 0 0 0 10 PSC 74 49 73 51 / 0 0 0 0 YKM 70 46 69 46 / 10 10 10 10 HRI 74 47 74 50 / 0 0 0 0 ELN 61 42 61 44 / 30 20 30 30 RDM 78 41 77 43 / 0 0 0 0 LGD 75 46 74 48 / 0 0 0 0 GCD 77 44 74 48 / 0 0 0 0 DLS 71 47 69 50 / 0 0 10 10

PDT WATCHES/WARNINGS/ADVISORIES

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