Clouds build this morning and we have rain likely moving into the state by midday, coming in from the west. A strong storm complex exited the central plains yesterday and moved into the WCB. The rain that we are seeing knocking on the door today is part of the initial bands of moisture around this circulation, even though the low is still well off back to the west. So, the action today will be slow moving and somewhat scattered through the day. The moisture starts in western Indiana around midday and then spreads east through the rest of the afternoon and evening. We see the second round of moisture tomorrow, and then scattered action still cannot be ruled out for Sunday. However, from beginning to end, we will see a frequency of precipitation fall off through the period. We are going to leave our cumulative 2.5-day rain totals at a few hundredths to a quarter of an inch on the low end, and .75” on the top end. There still is a chance of a few thunderstorms, but if they happen at all, it will be overnight tonight into tomorrow. We mention this because any thunderstorm could give locally 1”+ spots of rain, but we are leaving that out of the combined totals at this time. Here is the latest map of cumulative rains through the end of the weekend.
No change in the Monday-Tuesday outlook, as we have sunny, dry, less humid air in store for the entire state. Temps will stay near normal for this period, but overnight lows will be pleasantly cool.
We are throwing out some changes for the second half of the week next week. Normally we do not like to make major changes to our forecast based on only one model run. But, given that we are working into a weekend, we think we need to advance these thoughts forward to allow planning ahead of the weekend. We see rain and thunderstorms working into the state starting at some point overnight Tuesday night into Wednesday morning. The rains then continue through Wednesday, Thursday, and Friday at least. Models split on next weekend, with the Euro drying out, and the GFS bringing more rain. Who is right? We don’t know, and at this point, it really does not matter. There is potential for very good rains out of the 3 finishing days of the week, regardless of the weekend. Right now, we see a potential for half to 1.5” combined rains, and if we see additional moisture for the weekend, it could add another inch. Coverage of the rains may be as high as 80%. This is a major change in pattern, a change we do not make lightly, but we want to advance it now, because previous forecasts would have had a large enough window to cut hay, for example, …and this new outlook does not. The map above shows 10-day rain totals…this includes our weekend totals from the top map…and subtracting that would give you the full potential of action from Wednesday forward next week!
The extended period features a little less confidence this morning. A lot of it has to do with the uncertainty as to how the 10-day period ends. IF we are dry for next Saturday and Sunday, we likely see that hold into Labor Day and see a nice dry stretch behind next week’s strong front. Later in the period, upper-level high pressure settles in and keeps us mostly dry. However, if next week’s fronts stalls or slows, bringing more rain for the weekend, we see that stretching on a few additional days, before that same upper level high can move in. So, uncertainty at the front…but we still are gravitating toward a drier type solution like we have had previously. We are going to keep significant precipitation out of the 11-16 day window, allowing for only a few scattered hits and miss the pop up showers. This fits with our overall pattern thoughts that we start to trend drier as a pattern for the month of September over Indiana.