Frost/Freeze in Blue Mountain Foothills, Washington

The mesonet stationEW4185 Lowden reported at or below freezing temperatures between 0201 to 0658. The mesonet station K7KLA reported at or below freezing temperatures between 0504 to 0634. Several other stations across the area reported temperatures at or below freezing for several hours the morning of the 20th.

Clear skies in combination with dry flow regimes aloft resulted in good radiative cooling taking place at the surface. Temperatures in the morning had dropped to or below freezing for several hours in lower elevation locations between April 18th to the 20th.