textproduct: Pendleton

DISCUSSION

Current satellite and radar imagery show light returns approaching the Upper Slopes of WA Cascades and over portions of the Northern Blues. Webcams are showing light rain along I-90 between Easton and Snoqualmie Pass with grounded snow near the roads. In addition to that, Santiam Pass along US-20 remains to have roads covered in snow, which is advised to drive carefully when traveling on snow-covered, silky roads in that area.

Winter Storm Warnings will remain in effect until 4PM today for the WA/OR Cascades and Northern Blue Mountains. The shortwave trough will continue moving eastward, leaving light precip behind as the upper ridge approaches to the PacNW. This could potentially bring another inch or 2 of snow accumulations over the WA/OR Cascades and Northern Blues. However, this system will begin tampering off around 4PM and onward as snow levels gradually increase to 3kft and above, leaving it to be mostly light rain/drizzle for those areas (>70% chance). The WA Cascades will see gusty winds of 25-35 mph at its peak during these afternoon hours before gradually decreasing this evening. Visibilities could be impact driving conditions over the I- 90 corridor with surface snow blowing in the air, especially when traveling through Snoqualmie Pass. The crest of the Upper WA Cascades may reach to 45 mph through evening hours today, but confidence is low on the extent (<30%).

The upper-level ridge will make its way across the region starting Friday onward. Our forecast area will dry through late Saturday afternoon, but precip may return Saturday evening starting with the upper WA Cascades being clipped from a frontal system due to a closed low over the coast of British Columbia. Light snow may develop over the WA Cascades, though chances are low (<20%). Sunday through late Monday morning, the Northern Blues may see a light rain/snow mix with light rain across OR Cascades and the Gorge, but PoP chances will be 15-30%. Breezy conditions will develop late Saturday morning through early Sunday morning up to 20-25 mph between portions of central OR and the eastern mountains. Gusts of 20-25 mph over the Grande Ronde Valley and the Wallowas might continue lingering for Sunday evening hours, but confidence is about 35%. Feaster/97

AVIATION...00Z TAFS

VFR conditions are expected at most TAF sites through the period. However, there could be some MVFR conditions at DLS and ALW early Friday morning. Gusty winds in the 20 to 30 kt range have been impacting all sites except BDN, RDM and DLS much of today. These winds should decrease this evening to 10 kts or less. All sites will be 10 kts or less for the remainder of the period.

PRELIMINARY POINT TEMPS/POPS

PDT 32 50 29 46 / 20 10 0 0 ALW 35 49 33 45 / 30 10 0 0 PSC 34 50 29 43 / 10 10 0 0 YKM 30 45 29 42 / 10 0 0 0 HRI 33 50 29 43 / 10 10 0 0 ELN 28 41 26 38 / 10 0 0 0 RDM 22 46 25 50 / 0 0 0 0 LGD 31 43 29 43 / 40 10 0 0 GCD 27 43 26 47 / 10 0 0 0 DLS 35 47 32 45 / 30 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

OR...Winter Storm Warning until 4 PM PST this afternoon for ORZ502- 509.

WA...Winter Storm Warning until 4 PM PST this afternoon for WAZ030- 522-523.