Yet Another Unusual Day on the Summit
2014-09-25 18:58:00.000 – Mike Dorfman, Weather Observer/IT Specialist
When I woke up I was surprised to see relative humidity in the single digits at just
four percent, all thanks to a high pressure system pushing down over the region. After
a quick glance outside, I realized another interesting phenomenon had set up overnight-a
subsidence inversion. Inversions occur when the temperature increases with height
(normally they decrease with height). One type of inversion, a subsidence inversion,
occurs when sinking air warms up. An inversion often sets up at the boundary between
this sinking layer of air and the air below it. Below the inversion, you often see a
layer of haze due to the trapped air. I could clearly see this boundary on the horizon,
below which sat moist, warm air and above which sat clear, dry air. I caught a picture
(see attached) of the inversion boundary halfway up Mount LaFayette and Mount
Moosilauke. Turbulent air at the surface often destroys inversions since the separate
parcels of air will be mixed together, so we were lucky to get a calm day to support the
formation of this interesting phenomenon!
Mike Dorfman, Weather Observer/IT Specialist
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