Frost/Freeze in Foothills of the Northern Blue Mountains of Oregon, Oregon

The ASOS KPDT recorded temperatures at or below 32 degrees for approximately 11 hours ending at 1015 PDT. The Oregon DOT station OD191 recorded temperatures at or below 32 degrees for approximately 11 hours ending at 1046 PDT. The mesonet station DW9612 Umapine recorded temperatures at or below 32 degrees for approximately 11 hours ending at 0931 PDT. The Mesonet station EW7174 Adams4w recorded temperatures at or below 32 degrees for approximately 13 hours ending at 1015 PDT. Most stations in the zone recorded morning low temperatrues below 28 degrees.

Increasing northerly flow reinforced by a cold arctic airmass behind a shortwave trough passage starting October 26th lead to temperatures region-wide dropping well below normal. Overnight temperatures across the lower elevations in the intermountain Pacific Northwest were able to cool well below freezing across much the region for much of the overnight period. This lead to all lower elevation zones experiencing their end of season freeze by the morning of October 28th.