Cone Clouds

Observation by Anna R John:

Unusual groups of cone clouds. Next few days, we had record high temperature in our area (as well as other parts of Alaska).

Rick Thoman, Climate Scientist with the Alaska Center for Climate Assessment and Policy, writes:

These are quite impressive photos. Based on the images and the weather conditions in early July, these clouds probably originated as the mid-level clouds with the narrow part of the cone being precipitation falling from the cloud that is evaporating in the warm dry atmosphere below the bottom of the clouds. So, in meteorological terminology, these would be "altocumulus castellanus with virga." Altocumulus castellanus differ from more typical summer cumulus clouds in that they form not from heating of the ground but from moisture and cooling in the middle levels of the atmosphere (say, 6 to 14 thousand feet above the ground). Because the precipitation is evaporating before reaching the ground, it's known as "virga."

Comments from LEO Editors:

As seen in the Alaska Climate Research Center figure below, temperatures were above normal in many parts of the state. Temperatures in the Bethel area were approximately 5 degrees above normal. According to the National Oceanic and Atmospheric Association NOAA, Alaska often experiences warmer temperatures during El Nino, but the correlation between temperatures this year and the current El Nino conditions are weak - making these temperatures particularly unusual. Erica Lujan