Isolated Showers Aren't Enough
by Joel Young, Meteorologist/Reporter
July 22, 2012 11:18 PM
We’re several weeks into the current drought situation, and although we have been seeing more isolated showers and thunderstorms over the past few days; the drought is still getting worse. The most recent drought monitor shows just how quickly the drought is spreading. In this image, you can see that drought conditions in SE South Dakota, SW Minnesota, and NW Iowa have gone from a moderate to severe drought in a matter of days.
Ironically, many of the same areas dealing with the severe drought are seeing these isolated showers and thunderstorms. So if that’s the case, why aren’t we seeing any improvements? Obviously, the isolated nature of the rain is part of the reason; but wouldn’t the heavier rainfall associated with these storms have some effect? Unfortunately, only a very small portion of the rainwater actually becomes beneficial to the soil. The rest of it either evaporates or runs off to rivers and streams before it can be absorbed into the ground.
So what’s it going to take for things to improve? As we have mentioned before, one of the reasons for the dry conditions is the positioning of the jet stream. For the past few weeks, it has been curving far to our north, steering every chance of widespread beneficial rainfall into northern Canada. Without this upper-level support, we have been depending solely on the heat to get a few showers going. The images below show the jet stream’s position two weeks ago compared to its position Sunday morning.
Thankfully, we are finally seeing the jet stream inch its way to the south; but it still has a long way to go before we can get a good storm system to pass through our area with a good supply of rainfall. It has helped to get a few scattered thunderstorms to fire up, but there are many other pieces missing to the puzzle. Of course, until they all fall into place; we’ll take all we can get.