Melting snow, added rain and snow early, plus little to no wind leads to a very foggy Thursday night. Visibility will be very low for a time early tonight with some improvement as cooler air returns. Lower temperatures though the night will add another hazard, freezing drizzle and freezing fog. Dense fog and slick spots are a real possibility for early Friday morning.
WINTER STORM WATCH
The weekend storm is a complex one and is still in its incubative stage out in the Rockies late Thursday night. The storm will emerge Friday and begin to take shape through the day. Overnight computers are coming more in line with the storm track, a southern route but critical keys are still up for debate.
We start with the track - a southern route favors more wintry types of weather here but will include more of a combination of ice and sleet. Rain is possible further south in far south-central Indiana especially early Saturday.
MORE SNOW IS COMING
Moisture is plentiful! The liquid available for the storm is anywhere from a half-inch to over one inch. Ample amounts of snow can fall when the supply is that high, however not all will fall as snow. As of Thursday evening we have taken the average off seven machines specific to Indianapolis is 5.1" of snowfall with a wide spread of 3.7" to 8.8".
From a multi-model ensemble run by the National Weather Service's Weather Prediction Center, the probability of a 4" snowfall or greater is quite high for much of the state and across a large portion of the nation. Over two dozen states are under some form of winter advisory Thursday night for the upcoming weekend.
There will be two types of snow with the storm as well. A wet snow will fall early Saturday and Saturday afternoon then as the colder air is injected into the storm, a drier and fluffier brand will be deposited. When the air is colder, the snow production is higher will lesser amounts of moisture.
We noted that as the storm becomes more defined as the polar air is injected into it late Saturday leading to a secondary band of snow ('deformation zone') possibly over east and southeast Indiana. It's a new trend and will monitor this scenario closely.
Not carved in stone and subject to change, snowfall amounts will be healthy across the state and may vary widely. With possible two heavier bands associated with the storm, another factor is freezing rain or sleet.
COATING OF ICE
There are strong indications that a coating of ice could occur along and south of the I-70 corridor as the storm gets underway and prior to the shift or second have snow band develops. This could lead to some reduced snowfall production.
Arctic air flows into the state and the aforementioned polar jet stream will allow the storm to deepen and a large wind field to assemble. Throw in falling temperatures and gusty winds of up to 35 mph and we have a bitter, winter scenario here by Saturday night. Travel may be dangerous and conditions could be life-threatening with this storm. Be sure to check back for all the latest updates online and on air. New data will be available prior to the 10 and 11 p.m. newscasts on FOX59.