Another Messy 7-Day Forecast
June 11, 2012 8:40 PM
After a break in the action Monday for our entire area, looks like we will be gearing up for more scattered wet weather as we head to the latter half of Tuesday all the way through this upcoming weekend. Several waves will likely make their way through the area over the next few days, combine those waves with Gulf of Mexico moisture and plenty of heat, and you have the recipe for scattered thunderstorms just about everyday. Now remember that these are summertime thunderstorms, which means that not everyone will get wet everyday, but some rain here and there can be expected. However, the rain that does fall will likely be quite heavy. So storms may not last all that long, but can put down some impressive amounts.
It is unfortunate that we are talking about more rainfall because much of our area doesn’t need anymore. Now, I realize that there are a few locations that could use some water, but about 85% of our area could go a couple weeks before needing a drop of moisture. Check out the picture below. This image shows the departure from average rainfall over the last 90 days.
You can see that many areas, especially in the east have seen above average rainfall. In some cases, more then double their typical average with Pipestone, MN almost 8 inches above the 90 day average. However, there are a couple of places that could use a little water with parts of Gregory and Charles Mix county hurting the most, shy some 6 inches from the 90 day average. But like it or not, the potential for heavy rain is in the forecast.
With the Gulf of Mexico opening up, some heavy rain is possible with the thunderstorms through the end of the week. But what do I mean by the Gulf of Mexico “opening up?” Well that refers to moisture transporting directly to South Dakota. A strong ridge of high pressure sets up in the eastern U.S. With clockwise flow around that strong high and the jet stream moving from southwest to northeast, this allows unimpeded flow straight from the Gulf to South Dakota with persistent southerly winds. This set up give South Dakota the most humid air it could possibly have at any point during the year. The more humidity there is, the more rain can be produced by storms, and the more can fall to the ground. Just look at the rainfall forecast for the next 5 days according to the Hydrometeorological Prediction Center.
You can see that much of our area could get 1-2 inches, but remember that thunderstorms can produce very heavy rainfall for localized areas so if some clusters of storms get going, local areas could get well over the 1-2 inch mark, especially if those locations get hit more then once in the upcoming few days.
Well, if you don’t want to hear more about the upcoming rain then you aren’t going to like this either. Check out the forecast graphic from the Climate Prediction Center.
This shows that heavy rain will be a possibility across much of our area on the 14th and 15th of June which is Thursday and Friday. So stock up on the rain boots and umbrellas now because it could be a pretty wet few days for some of us.