A Storm With Big Impacts
It appears a major winter storm will impact parts of the area Monday into Tuesday. This storm will have multiple hazards, and I am going to try to hi-lite each of those hazards and what areas they will impact.
The first will be the potential for flooding. This system is going to bring copious amounts of moisture into the Midwest and Ohio Valley. Our latest forecast guidance shows that most of the state could receive over 3 inches of liquid equivalent precipitation if not as much as 6 inches! This combined with the snow melt and already over-saturated grounds could create a dangerous flooding situation.
It looks like rain will develop during the day on Monday and could be heavy at times across the entire state. A cold front will march through Indiana in the early afternoon hours and as the cold front moves across the state from Northwest to Southeast, a few thunderstorms could develop along the front.
As the front moves through the area it appears Arctic air will flood into the area and this air will surge under an already powerful warm air mass that will be in place across a large portion of Central Indiana. With plenty of moisture redeveloping behind the cold front as a secondary low pressure forms in Arkansas, this will set the stage for what could be a major ice storm for Central Indiana with a sleet and snow threat across Northern Indiana.
The most significant ice accumulations are likely from Crawfordsville to Noblesville over to Muncie, Winchester and Greenville. I think there is a definite possibility of at least a half inch of ice accumulation and that could be very conservative. One row of counties farther South including the Terre Haute, Indianapolis and Richmond areas will likely see lighter ice amounts, but could see up to a quarter of an inch of ice accumulation.
Farther North from Lafayette to Fort Wayne the potential exists for some major sleet and snow accumulations. Sleet will likely cut down on snowfall amounts, but 3-6 inches of combined snow and sleet is possible.
Finally across far Northern Indiana including South Bend, snow will be the predominant precipitation type and 6-10 inches if not more of snow will fall.
For all of you South of Interstate 70, you should escape any risk of winter weather but will likely be impacted by very heavy rain and even some thunderstorms and as I said before the potential for flooding.
This is a very powerful storm system and will likely have a significant impact on the entire area. I would look for winter storm watches and flood watches to be issued by the National Weather Service Offices this afternoon.