textproduct: Pendleton

DISCUSSION

Radar shows precipitation associated with the PacNW atmospheric river still producing light showers across the Washington Cascades. Rain will continue in this warm system for the next 12 to 24 hours, with the heaviest rains pushing through the slopes of the WA Cascades in the overnight to early morning hours Thursday. Guidance shows an additional 2.4 to 6.3 inches of rain in the WA Cascade crest (especially closer to the Snoqualmie Pass area) through Saturday (25 to 75 percent chance). This will continue to bring hydrology concerns with rivers along the Yakima and Naches rivers through Friday with rivers rising to Minor level, with Yakima at Horlick, Kiona, and Parker & Naches near Naches expected to be in Moderate level. Rivers will greatly improve going into the weekend with most banks going below the flood stage. Kiona will see a slight lag in the crest that is expected to occur through the early morning hours of Saturday. Flood Watches will continue through Friday morning with Flood Warnings across the flooded rivers being in effect until further notice. Conditions will greatly dry out Friday through Saturday.

Our next major focus is the wind threat bringing breezy/windy conditions across the Basin, Simcole Highlands, and North Central Oregon in effect until 7 AM tomorrow morning. Observation winds showed 70-80 mph gusts at Rattlesnake and other parts of the Hanford Reach area, so went ahead and upgraded the advisory for the WA Basin to a High Wind Warning through the normal time of the original advisory. Other parts of the WA Basin are observing gusts up to 55 mph with sustained 30 to 40 mph. Winds are expected to be at their peak currently and will decrease in strength going through tonight and the overnight hours. By tomorrow afternoon, winds will drop to 15 to 25 mph area wide (65 to 85 percent chance).

Our next weather system will occur through early next week with upper level southwest flow bringing in moisture advection into the area embedded with a shortwave to bring a relatively colder system than the one we're seeing today. Low valley light rain is expected to take place with mountain snow showers expecting to develop Tuesday with snow levels dropping to 4000 to 5000 feet (30 to 50 percent chance). We'll see a slight cooling trend going into early next week, with temperatures dropping from mostly the 60s into the low to mid 50s, but low temps will stay above freezing for most of the highly populated communities (35 to 55 percent chance).

AVIATION...00Z TAFs

VFR conditions to prevail through the period. Breezy winds 12-20kts with gusts to around 25kts will continue this afternoon at site RDM. Winds 12-20kts with gusts 25-30kts will continue at sites DLS/BDN into this evening, with these winds continuing overnight at site YKM. Winds of 18-30kts with gusts 25-40kts will persist through tomorrow morning at sites PDT/ALW/PSC, with winds becoming 12-18kts and gusts up to 25kts between 14-17Z. Lawhorn/82

PRELIMINARY POINT TEMPS/POPS

PDT 51 60 43 59 / 0 10 10 0 ALW 54 58 48 58 / 10 20 30 10 PSC 55 62 44 57 / 0 10 10 0 YKM 48 59 41 58 / 20 10 10 0 HRI 53 62 45 58 / 0 10 10 0 ELN 44 52 39 53 / 30 20 30 10 RDM 37 59 31 59 / 0 0 0 0 LGD 45 55 41 57 / 0 20 20 10 GCD 39 56 36 56 / 0 0 10 0 DLS 55 60 47 59 / 50 20 30 0

PDT WATCHES/WARNINGS/ADVISORIES

OR...Wind Advisory until 7 AM PST Thursday for ORZ041-044-507-508-510.

WA...Wind Advisory until 7 AM PST Thursday for WAZ024-027-029-521.

Flood Watch through Friday morning for WAZ026-027-521>523.

High Wind Warning until 7 AM PST Thursday for WAZ028.