Hey Ray: Heat Domes
PITTSBURGH (KDKA) - It is summer, and hot weather in the summertime is to be expected.
We even showed you in a previous segment why our temperatures are the warmest after the Summer Solstice. Our average temperatures peak in mid-July.
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That is normal heat, though. Our subject today deals with abnormal heat - intense, abnormally hot conditions.
You may be familiar with the term "Heat Wave" which is a period of unusually hot and humid weather that lasts more than two days. Some abnormally hot and humid conditions can linger for days to weeks.
We call this phenomenon a "Heat Dome".
According to the National Weather Service, heat domes happen when an area of high pressure becomes very persistent and traps heat over a particular area.
That particular area can even encompass several states!
The National Weather Service links heat domes to the behavior of the jet stream.
The jet stream divides the warmer air from the south from the colder air to the north.
When the jet stream pushes northward, warm air starts to move in from the south. Sometimes, the jet stream moves north and slows down. This ridge results in a big area of high pressure. Very stubborn high pressure, which is sinking, drying air, leaving skies clear.
This warms up the surface in a couple of ways.
First, as air sinks and compresses, it warms. Second, with clear skies, the Sun heats the surface which heats the air.
Think about it. If you are in the Sun with no shade, you continue to warm up. Clear skies work the same way. When there are no clouds to block that incoming solar energy, it will get hotter.
Several days or weeks of this scenario leads to a situation where heat continues to build each day. This leads to dangerously hot conditions.
