An impressive shot of early season arctic air will come at us in a 1-2 punch format to wrap up the week and head into early next week. Before we dig deeper into the details, let’s keep in mind averages for November 9th-15th include lows in the middle 30s and highs in the middle 50s. Multiple days during that time frame will feature highs where our average lows should be (if not even colder a couple days) and overnight lows deep into the 20s (10s perhaps on a couple nights).
The initial blast of cold air will blow into town Thursday night and Friday and will be accompanied by a chilly rain ending as a touch of wet snow across central Indiana. This will be a “novelty” level event for most across the region, but there could be a couple of slushy accumulation reports- especially north of the city.
The bigger story will be localized, but intense snow bursts that will likely develop as the true push of arctic air arrives Friday evening. These will be accompanied by strong and gusty winds, as well.
We’ll awake to temperatures in the lower 20s across most of central Indiana Saturday morning. By this point in time, attention will shift to what awaits during early stages of the new work week. While details are murky with respect to the specifics associated with an eastern storm, cold air will be reinforced Monday night into Tuesday.
Keep a note in the back of your mind to check back often over the weekend concerning the forecast for early next week. Model bias (“progressive” GFS; “sluggish” Euro) appears to be running rampant from this distance and what will likely be the ultimate result is something in between. The sensible weather that would result is the opportunity for perhaps a better chance of more widespread accumulating snow across portions of the Ohio Valley Monday night into Tuesday.
Snow prospects aside, confidence remains high that the upcoming cold pattern will be the most significant so early since the early season bitter blast of air in November ’14!
Additional rainfall totals of 1″ to 2″ with locally heavier amounts are a good bet in that Monday night – Tuesday time frame.
While we’ll certainly turn colder behind this storm system, the true early season push of arctic air will wait a couple of days to arrive- Thursday afternoon into Friday. Not only will this be the coldest air of the season (lower-middle 20s Friday morning and likely colder next Saturday), but the first flakes of the season are also likely to fly across central Indiana to wrap up the work week. Furthermore, 
Don’t look now, but more “fun and games” await the following week…
More specific to Indianapolis, here’s the monthly temperature breakdown so far for 2018:
While we have conflicting temperature ideas, both suggest a drier than average month emerging:
At the end of the day, our call on May’s forecast from mid-April would be for an early cooler than average start before flipping towards more of a seasonable to slightly warmer than normal regime. Our idea all along this spring has been that when this pattern flips, the potential is present to jump right to a summery feel. In the face of the new European Weeklies, we still feel this warmer idea mid and late May is on the table. We’re in agreement with the data of a drier than average month.
