If you live anywhere on the eastern half of the United States, you’ve probably been sweating it out over the past several days in what certainly feels like the warmest week yet for the season. The cause of the oppressive weather? A large mid-level ridge centered over the Ohio Valley — large enough to be easily visible from space.
The image above [click here for hi-res] was taken by the GOES East satellite at 12:45 p.m. EDT on July 15. The clear area over Ohio shows the center of the system, which has been driving temperatures up into the 90s for much of the eastern U.S. and is expected to expand into the plains by mid-week. Along with increased humidity, heat index values will exceed 100 ºF and even approach 110 ºF on Friday.
From the NASA Image of the Day page:
A very anomalous weather pattern is in place over the U.S. for mid-July. Trapped between an upper level ridge centered over the Ohio Valley and the closed upper level low over the Texas/Oklahoma border, atypical hot, muggy air is stifling a broad swath of the eastern U.S. The closed low is expected to drift west toward New Mexico bringing heavy, localized rain to some areas and temperatures running 10-20 degrees below mid-July averages. Across the east, temperatures will warm well into the 90s and stay there through the week. (NOAA)
As of the time of this writing heat advisories are in place in many parts of Michigan, southern Minnesota, and southern New England, and excessive heat warnings are active in eastern Pennsylvania and west central New Jersey. (Source)
Meanwhile, a closed low — seen above as a large, moisture-laden spiraling cloud system — is moving west across Texas and New Mexico, and is expected to bring lower-than-average temperatures along with heavy rains and flash flooding.
At an altitude of 22,336 miles, the geosynchronous GOES satellites continuously provide observations of 60 percent of the Earth including the continental United States, providing weather monitoring and forecast operations as well as a continuous and reliable stream of environmental information and severe weather warnings.
This post by Jason Major originally appeared on Universe Today. It has been republished with permission.