THE LAST WEEKEND OF SUMMER...
Before we get to the last weekend of "official summer" I did want to mention that drought, which has been occurring across much of the area the duration of the summer, has further expanded and intensified. According to the latest drought index much of my area near and north of I-80 is experiencing moderate to severe drought. To the south, a buffer of abnormally dry conditions has even developed over my southern counties which until recently had largely avoided the dryness up north.
Below you can see the biggest changes over the past week are found in my southern counties where normal soil conditions have been replaced with abnormally dry ones, especially in Se Iowa.
None of this is shocking as much of the area is now going on two weeks without rainfall. Here's what's fallen the past 7 days. Nothing south of HWY 30.
Here's the percent of mean for the first half of September. There's some spots with less than 10 percent of what's typical.
Frankly, I'm not very excited about precipitation chances the rest of the month. There is a disturbance that arrives late Friday or Friday evening that could scare up a few showers and storms. However, some capping issues are indicated and forcing is waning and the overall set-up just doesn't look conducive for widespread or beneficial rain. If a few showers or storms do fire, they look spotty and light. A few lucky spots might see 1/10 to 2/10ths of an inch but most areas will see less (if any at all). Here's what the latest guidance is indicating. You will notice all the models are consistent in showing the area from the Quad Cities southeast with the best chances for some light amounts.
The EURO
The GFS
The 3k NAM
Once this weak wave passes the remainder of the weekend and the majority of Monday looks dry as well. During this period highs are expected to be well above normal in the range of 85-90 Friday through Monday. Typical highs should be around 75 so we're going to be way above that and the last weekend of summer will go out on a toasty note. Dry and warm, that's fitting as it pretty much encapsulates the entire summer of 2021.
Beyond that, I foresee a vigorous disturbance entering the region Monday night or early Tuesday. The latest trends are for a more progressive system which allows the cold front to pass a day earlier that had been recently indicated. It also looks like the window for precipitation will be shorter as well which diminishes the chances for significant rains. However, if we can get the frontal passage to coincide with maximum instability we might still have a shot at a broken line of storms that could produce some downpours in spots. These look to be fast movers so any rain won't last long and will have to come down fast and furious to amount to much. Not entirely out of the question. However, it's far too early to say how it plays out and we'll need to play the waiting game to get a better handle on the overall set-up
One thing is for sure and that's the fact much cooler air will surge into the Midwest behind the front Tuesday and Wednesday. The GFS shows readings Tuesday evening that are as much as 28 degrees cooler than 24 hours earlier.
Well, that's where things stand heading into the weekend. Thank God it's Friday and as always, roll weather...TS
