Frost/Freeze in Lower Columbia Basin, Washington

The ASOS KPSC reported at or below freezing temperatures between 0515 to 0655. The mesonet station K7KOG Kennewick reported at or below freezing temperatures between 0343 to 0549. Several other stations across the area reported temperatures at or below freezing for several hours the morning of the 18th.

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.