We’re watching a couple of quick moving weather systems that could impact portions of central Indiana through the middle of the work week.
The first system is crossing Illinois. It is a cold front, associated with an upper-level disturbance, that is moving to the east. A few light showers have developed ahead of the front in northern Indiana. A narrow line of precipitation – in the form of rain – is stretched north to south across Illinois.
The front is expected to continue moving east. As it does so, it will begin to move in to a slightly drier environment. As it does so, precipitation should begin to wane as it moves in to the Hoosier state.
As the disturbance passes over, it may be able to squeeze out just enough moisture to produce a few rain drops, mixing with a few snowflakes through sunrise.
Timing will be everything as temperatures are expected to fall to +/- 1° of the freezing mark at the surface by 7 a.m. Monday. If the disturbance brings the moisture earlier in the night, temperatures will be a couple degrees warmer allowing the precipitation to fall as all rain. If it arrives at sunrise, when the air temperature is coldest, there could be more snowflakes falling. At this time I am not expecting this to cause any issues for the morning commute, however if their is a little more moisture available in the atmosphere, there could be a brief period of freezing rain/drizzle and snow.
SECOND SYSTEM ARRIVES TUESDAY
A second system is taking aim on Indiana Tuesday morning. The upper-level energy for the system arrived over western Canada Sunday evening.
It will quickly dive to the southeast, arriving over Indiana Tuesday morning. Computer models suggest precipitation arriving in central Indiana early Tuesday morning and continuing through mid-morning.
Latest data from our high-resolution computer model suggests the precipitation falls mainly as rain Tuesday morning, but there are few computer models that suggests the precipitation could fall in the form of snow for some locations, mainly north and northeast of Indianapolis.
Now that the upper-level energy is onshore, we should be able to better sample the energy and put that data in to the computer models. Sunday night’s computer model runs and Monday morning runs should do a better job resolving what could happen with Tuesday morning.
All of that being said, this does not look like a significant impact for central Indiana. Some areas could receive a couple tenths of an inch of wet snow, while most areas receive rain. Stay tuned!