2016-07-13 16:26:28.000 – Andrea LaRocca, Summit Intern
It’s the start to another great week here on Mount Washington. To start the week off with a bang, we have the potential for some thunderstorms this evening. With plenty of sunshine still peeking through, we’re crossing our fingers for a good one today. With the likelihood of us being in and out of the clouds for the next couple of days and rain showers possible, the welcome sight of severe weather is always one we will take. As clouds form during the day, a consequence of day time heating, small pockets of warm air channels form and rise. These air channels, also known as thermals, create means for enhanced lift or updrafts in the atmosphere. These thermal updrafts are not visible to eye, however you can spot them fairly easily by looking for birds that “ride” them—if you see a bird hovering over an area without flapping its wings, it is likely that they are utilizing this natural phenomenon. These updrafts allow air parcels to cool and condense at a rapid pace in a process called convection.
While convection alone is not enough to form thunderstorms, unstable air, or air that continues to rise when “nudged”, provides favorable conditions for this convection to realize its potential and form a thunderstorm. A culmination of various atmospheric processes can cause a thunderstorm to turn severe, such as ample moisture advection, strong upper-level shear (or how the winds turn with height), sufficient day time heat and fast updraft speeds. While tonight’s storms are not expected to produce tornadoes, the potential for strong winds, hail and lightning cannot be ruled out. So remember to always be weather aware and when thunder roars, go indoors.
Forming cumulus clouds in the distance
Andrea LaRocca, Summit Intern