Frost/Freeze in John Day Basin, Oregon

The mesonet station CW2286 Monument recorded temperatures at or below 32 degrees for approximately 9 hours starting at 0000 PDT. The USCRN site SHRO3 recorded temperatures at or below 32 degrees for approximately 9 hours starting at 2210 PDT. The Oregon DOT station OD200 recorded temperatures at or below 32 degrees for approximately 11 hours starting at 2156 PDT.

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.