Wednesday, July 01, 2009
Weather columnist Kevin Myatt: We stay cool while 'heat dome' smothers others
Kevin Myatt is The Roanoke Times' weather columnist.
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So far this summer, the heat is on somewhere else.
One of the things to watch for in the summer weather pattern is where the "heat dome" sets up. The heat dome refers to a large high-pressure system -- essentially, a huge mound of stagnant, hot air -- that tends to park itself over at least one region of the country.
Underneath the heat dome, temperatures broil, and there's very little rain. But depending on how it sets up, regions outside the dome can experience cooler and/or rainy weather because of the high-pressure system's clockwise circulation.
So far in this early summer, the heat dome has set up over the south-central United States -- generally Texas, Arkansas, Oklahoma and surrounding states.
While that region has had temperatures in the 90s to near 100 several days, cold fronts and storm systems have traced the edges of the high and passed through the northern Plains and upper Midwest, sliding southeast toward our region.
But the high's clockwise flow has continued to cut off most moisture return from the Gulf of Mexico, so the cold fronts are passing mostly dry while reinforcing temperatures that are near or slightly below normal.
As the summer progresses, the location of the heat dome will largely determine our weather. If it stays away, so will the searing heat.
Kevin Myatt's column runs Monday, Wednesday and Friday.
