Frost/Freeze in Blue Mountain Foothills, Washington

The mesonet station EW4185 Lowden reported at or below freezing temperatures between 0134 to 0716. The mesonet station DW6278 Walla Walla reported at or below freezing temperatures between 0330 to 0715. Several other stations across the area reported temperatures at or below freezing for several hours the morning of the 22nd.

Clear skies in combination with dry flow regimes aloft resulted in good radiative cooling taking place at the surface. Temperatures in the morning had drop to or below freezing for several lower elevation locations between April 22nd to the 23rd.