In the world of weather, it is often feast or famine! In today’s IQ Weather blog, we can see both at work at the same time!
Those of you have taken our course understand the huge influence that the oceans play in setting up weather patterns. Our current La Nina ocean pattern is weakening, but is still helping to lock a drought into place over the southwestern United States. The U.S. Drought Monitor keeps track of long-term drought severity, and here is a look at the latest areas of drought in the U.S.
Once this ocean pattern shifts a bit, and continues to weaken, hopefully we’ll see some rain returning to this parched area of the country. The satellite picture shows this area of drought, and since it is so dry, there is very little moisture to turn into clouds. Once a drought gets going, it can take a long time to reverse the trends.
Since January the area of drought has slipped a bit farther to the west. Here is how the situation looked early this year.
That was the famine part of the equation. The feast comes with the return of warm, humid air to much of the Great Plains states. As we enter the summer months, the threat of tornadoes diminishes a bit, but the risk for very strong and windy storms called “mesoscale convective systems” (MCS) rises. They are impressive looking storms, whether you are looking at them on the satellite:
These storms can cover hundreds of miles at a time and usually produce torrential rains, strong gusty winds, and sometimes large hail. These are relatively common in the summer months. They normally start out on the high plains in the afternoon and grow in size and strength during the night-time hours. They may travel over a thousand miles before they finally weaken and come to an end. And, the location where they fall apart, is often the focus for new thunderstorm development later on.
Mesoscale convective systems are quite interesting and complex! Sometimes there are new MCS’s that form night after night on the front range of the Rocky Mountains later in the summer. And that helps to spread rain across the very dry areas in the high plains!
You can easily watch these systems forma and dissipate on the new high resolution GOES 16 satellite loops! It’s fun to track them and to learn about how they behave. And, always pay attention when an MCS may affect your area, as severe weather can be possible!
Stay tuned for more IQ Weather blogs!
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