The first accumulating snow event of the young 2018-2019 season is upon us. Thankfully, this won’t be any sort of “blockbuster” storm, but instead serve to gently “ease us” into the new snow season.
Upper level energy will eject out of the Plains today and push towards the Ohio Valley Monday. At the same time, surface low pressure will develop along the Gulf Coast before scooting off to the eastern seaboard and tracking north Monday night and Tuesday. Initially, it’ll take some time to moisten up what will be a relatively dry air mass, but a mix of cold rain and wet snow should begin making it to the surface during the late morning and early afternoon.
8a forecast radar. Image courtesy of Weathermodels.com.
Precipitation will become more widespread as we push into the late afternoon and early evening hours with the predominant precipitation type by this time falling in the form of snow across central Indiana- including Indianapolis.
6p forecast radar. Image courtesy of Weathermodels.com.
Widespread light snow will be falling tomorrow night across the region.
Forecast radar 10p Monday. Image courtesy of Weathermodels.com.
Snow will begin to diminish after midnight and by the time all is said and done, we forecast a general 1″ to 2″ across most of central Indiana. (Some localized lake effect snow showers may add to additional accumulation across north-central portions the central IN Tuesday morning into the afternoon).
We’re left with unseasonably cold conditions through the remainder of the week, followed by reinforcing cold air arriving next weekend…
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…
II. TD 14 will strengthen into Tropical Storm Michael later today and eventually a hurricane before making landfall along the Florida panhandle during the middle of the week. The remnant moisture of Michael will then race northeast and impact the flood-ravaged Carolinas during the latter stages of the work week.
III. As Michael’s remnant moisture tracks northeast into the Carolinas, a strong cold front will sweep through the Mid West and Ohio Valley. Better chances of organized showers and thunderstorms will arrive ahead of the front Wednesday. Once the front passes, a dramatic wind shift to the northwest will push a MUCH cooler and drier air mass into the region.
IV. We note the PNA (Pacific North America pattern) is flipping to a positive state and that will drive a more sustained period of colder air during the medium and longer range period- or mid and late October.
The air will grow cold enough to support the potential of frost during the 5-10 day period on at least a couple of nights. Additionally, reinforcing chilly air may ignite the lake effect to our north and northeast during Week 2… “Times, they are a changing!”
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