INDIANAPOLIS — The forecast today is playing out as expected. Clouds are gradually increasing but very dry air at the surface means the increasing gray will have more bark than bite. We're expecting most daylight hours to remain dry with showers not arriving in the Indy metro area until after 6 p.m.
Showers reach the Illinois/Indiana border around 4-5 p.m. and spread west-to-east for the remainder of the day.
Showers won't likely reach eastern Indiana until between 8-9 p.m.
Prior to arrival, we'll have filtered sun through the cloud deck and highs in the mid to upper 50s. Showers this evening and overnight will be light and coverage gradually spreads out heading into Wednesday morning.
Though showers are possible at any time Wednesday, the odds of rain are only between 20-40% which means there will be many rain-free hours over your area despite a healthy deck of clouds.
We continue to focus on heavy rain and flood potential along a slow-moving boundary Thursday into the opening of the weekend.
Central Indiana will be located south of this front on Thursday, when much milder air (highs nearing 70°) and low-level moisture (dewpoints getting into the 50s and possibly 60s) build on a strengthening southwest wind.
A shield of rain and thunderstorms is expected to develop along the front as low-level wind fields increase to aid in the atmospheric lift.
Areas of rain become heavy and likely to "train" along the front with the upper level moving parallel along the front.
This ups the odds of excessive rainfall with this initial wave Thursday into early Friday morning.
It's uncertain when/where that wave ends, but there's a growing probability of another heavy wave moving through central Indiana with a strengthening low-pressure system Friday night into Saturday.
The combination of all these systems produces a wide swath of 2"-3"+ rainfall from Thursday morning to Saturday afternoon.
This will undoubtedly trigger areas of flooding and all of central Indiana is in the Level 2 (out of 5) zone for Excessive Rainfall potential during that time.
It's possible these probabilities climb as confidence grows on where there heaviest rainfall occurs.
Please stay tuned to the forecast and know that there's a growing chance of significant impacts to outdoor plans Saturday.