textproduct: Pendleton

KEY MESSAGES

- Above-normal temperatures and mostly dry conditions through this week into next week

- Wind Advisory in effect this afternoon and evening

- Periods of low relative humidity (10-20 percent) coupled with breezy to windy westerly winds Thursday and Friday through the Cascade gaps and across the Columbia Basin and Blue Mountain foothills

DISCUSSION

Although a stratus/marine layer and invading cirrus was overspreading much of the area west of the Cascades, the Eastern Columbia Gorge. Lower Columbia Basin was virtually cloud free late this morning, with only the exception of clusters of cumulus clouds popping off the southern Blue Mountains and Wallowas. For the Wind Advisory for this afternoon, Ellensburg is hitting around the lower end of gust criterion and was gusting between 45 and 50 mph over the last few hours with sustained speeds in excess of 30 mph. A shortwave is moving through the upper mean ridge in BC/upper Columbia Basin, through Tonight before the upper ridge becomes more amplified into Thursday across WA and OR. ECMWF/GFS20 and AI GFS all agree on another shortwave late Friday but the dry system will lead to little more than mountain showers for the Cascades. This wave should enhance wind gusts through gradients and momentum transfer on Friday, which could be another wind advisory afternoon though the Kittitas valley, parts of the foothills of the Blue Mountains and Simcoe Highlands with roughly 20 to 50% chances for wind gusts of 45 mph or greater based on NBM members. Temperatures through Thursday and Friday are not as warm but still will reach the 70s across the foothills and 80s through the Yakima Valley, Lower Columbia Basin Central Oregon and the John Day Basin, driving heat risk in to the Minor category, affecting individuals most sensitive to heat, and without cooling or hydration. In addition to the warm temps, the chances for measurable precipitation are virtually zero over the area well into next week and the 6 to 10 day outlook offers 50 to 70% chances for above normal temperatures and 40 to 50% chances for below normal precipitation. Russell/71

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

VFR conditions currently across all sites, which will stay the course through the period. Breezy winds of 20-30kts for all terminals through this evening, dissipating later tonight. The only exception will be KDLS, which will continue to experience breezy 20- 30kt winds into the early morning hours on Thursday. BKN-SCT 25kft ceilings this evening before clearing out overnight tonight. 75

FIRE WEATHER

Warm temperatures will drive down relative humidity with afternoons becoming breezy and locally windy, resulting in elevated fire weather conditions through the week. Winds on Thursday will slacken slightly so risk is lower but a more breezy Friday will lead to 20 to 50% chances for combined RH and Wind gusts of 20% and 20 mph. So beyond this afternoon,t he next most risk day is Friday, followed by a more muted risk on Sunday as winds are not anticipated to be particularly strong, but much warmer temperatures will drive down RH down to around 10% across the Ochoco John Day Highlands. Russell/71

HYDROLOGY

Expect a continued fall in the Naches River as the gage at Naches has already gone below the action level and Cliffdell gage is forecast to undergo a much slower fall, remaining above action stage and falling to 16.18 ft by Tuesday afternoon. Russell/71

Preliminary Point Temps/PoPs

PDT 82 52 76 50 / 0 0 0 0 ALW 82 54 76 53 / 0 0 0 0 PSC 89 56 82 55 / 0 0 0 0 YKM 88 50 82 50 / 0 0 0 0 HRI 85 54 79 53 / 0 0 0 0 ELN 80 47 77 47 / 0 0 0 0 RDM 83 43 80 41 / 0 0 0 0 LGD 81 47 74 43 / 0 0 0 0 GCD 81 45 77 43 / 0 0 0 0 DLS 83 53 79 50 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until 1 AM PDT Thursday for WAZ024-026-521. OR...Wind Advisory until 1 AM PDT Thursday for ORZ041-044-507-508- 510.