textproduct: Pendleton

DISCUSSION

A lingering stationary front (that's for all practicality a very slow moving cold front) has slowly pushed off to the Southeast, closer to the Oregon/Nevada/Idaho region. As the front continues to move away from the region, the low to mid level clouds that were in Central Oregon will begin to clear out as we head into the late afternoon hours. Light snow showers isolated to the Snoqualmie Pass area (40-50 PoPs) will continue through the overnight hours, bringing up to an additional inch of snow (80-90% chance) in the area.

Through the weekend: A ridge will develop over the PacNW region that will maintain dry, warmer conditions through Saturday morning. Current guidance shows high temperatures maintaining in the low to mid 50s through the lower elevation areas, with low temperatures rising at or near freezing on Saturday (>80% chance). Shower activity will resume Saturday going into Sunday as a closed-low will move just south of the area near the California/Oregon border. Rain with some areas of a wintry mix will be situated in the southern part of our region near Central Oregon through the John Day Highlands (50-70% chance) with the Atmospheric River's main impacts staying just south of the Pendleton/Tri-Cities area. Total precipitation amounts are likely to go up to a tenth of an inch of rain, with NBM not giving much more than a 15-20% chance of going above that threshold.

Tight pressure gradients will develop near the Ellensburg/Kittitas Valley, bringing breezy to locally windy conditions Thursday and Friday. Wind gusts of up to 35 to 45 mph might be common in the lower elevations of the valley, with gusty 30 to 40 mph possible in the lower Washington Columbia area, although not as great of a chance near the Kittitas Valley. NBM suggest 15-25% chances that the lower Columbia will develop wind gust greater than or equal to 40 mph, while the Kittas depict slightly higher chances at 25-35%. Despite that, not expecting any issuance of wind advisory highlights at this time as confidence remains low to medium that we will hit criteria below 3500 feet. Areas above 3500 feet will see much higher gusts as high as 50 mph (60-80% chances), although wind advisories are not issued for elevations this high.

Early next week: The low pressure system will continue to move east through early next week, tapering off precipitation chances by Monday lasting through Wednesday morning. Afterwards, guidance suggests another wet pattern to resume as we head into mid-week next week.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Visible satellite and mesonet observations indicated clear conditions for DLS/YKM/ALW/PDT and PSC this afternoon. Scattered to BKN cu field was also present on the imagery in the vicinity of BDN and RDM. Breezy to gusty westerly winds will return on Thursday afternoon, however gusts will end at most sites for the overnight hours. Based on HREF output, the best opportunity (if any) for getting low stratus/fog to develop is in the vicinity of PSC overnight, for which there is about a 25% chance for visibility less than one half miles. Russell/71

Preliminary Point Temps/PoPs

PDT 29 53 31 56 / 0 0 0 0 ALW 32 53 35 55 / 0 0 0 0 PSC 31 55 33 57 / 0 0 0 0 YKM 27 51 29 53 / 0 0 0 0 HRI 30 55 32 58 / 0 0 0 0 ELN 28 45 30 47 / 0 10 0 10 RDM 22 52 25 58 / 0 0 0 0 LGD 25 51 29 56 / 0 0 0 0 GCD 24 50 29 55 / 0 0 0 0 DLS 31 52 33 55 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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