textproduct: Pendleton

KEY MESSAGES

- Above-normal temperatures and mostly dry conditions through the week

- Breezy to windy each day Wednesday through Friday through the Cascade gaps and across the Columbia Basin and Blue Mountain foothills

- Periods of low relative humidity and breezy to windy westerly winds Thursday and Friday through the Cascade gaps and across the Columbia Basin and Blue Mountain foothills

DISCUSSION

Another mild overnight is anticipated in the 50s and even around 60 once again in the lower elevations (Columbia River Gorge). This afternoon and Wednesday will be the two warmest days of the week as the upper ridge sits squarely over the Cascades and Columbia Basin, with more of a subsident influence. Beyond Wednesday the flow aloft becomes slightly more south westerly with the ridge axis sliding into the interior NW region. Highs Wednesday will range from 60 to 70 degrees across the the northern Blue Mountains, to the upper 80s in sections of the lower Columbia Basin, Yakima Valley, Central Oregon and the John Day Basin. Based on NBM ensemble members, There is a 20 to 30% chance for highs to reach 90 degrees from Pasco to Richland and areas northwest along highway 240. Gusty westerly winds develop Wednesday afternoon across the Washington valleys and the Columbia Basin, as the NBM mean gusts showing 30 to 40 mph. The windiest day where it looks like the potential for a wind advisory could be needed is Friday where there is about a 20-50% chances for wind gusts exceeding 40 mph in the Simcoe Highlands and Kittitas Valley. Hot temperatures through the weekend beyond are anticipated as the 8 to 14 day outlook leans both dry and warm with a 33 to 40 percent chance for below normal precipitation and a 40 to 50 percent chance for above normal temperatures May 12-18.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

VFR conditions currently at all sites, which will stay the course through the period. Breezy winds at KDLS with gusts between 20-30kts are occurring, peaking this evening and lingering through Wednesday afternoon. Breezy winds of 15-20kts are also occurring for KRDM/KBDN. Elsewhere, winds will stay light and below 10kts until Wednesday afternoon, which widespread gusts of 15-25kts is expected at all terminals. 75

FIRE WEATHER

The region is currently in the green up phase so fuels in general are not in play for red flag criteria. Meteorological conditions will be dry with relative humidity falling below 20 percent on a more widespread basis Wednesday and onward. The RH values are the lowest Sunday and Monday when the NBM is forecasting temperatures in the upper 80s across all of the lower elevation areas and wind gusts in the 20 to 30 mph range each day.

HYDROLOGY

The Naches river continues to run high from recent melting, and will remain above action stage through Thursday Evening at Naches, and through Friday Night downstream and Cliffdell. High confidence exists with respect to dry conditions along the upstream basins (75-98%), so no additional runoff or rises are anticipated.

Preliminary Point Temps/PoPs

PDT 79 50 83 53 / 0 0 0 0 ALW 78 54 82 56 / 0 0 0 0 PSC 84 51 88 53 / 0 0 0 0 YKM 84 53 87 52 / 0 0 0 0 HRI 83 50 86 54 / 0 0 0 0 ELN 79 50 79 48 / 0 0 0 0 RDM 79 43 82 43 / 0 0 0 0 LGD 74 47 78 49 / 0 0 0 0 GCD 75 45 79 46 / 0 0 0 0 DLS 83 56 83 54 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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