The Latest On This Weekend’s Winter Storm

Good afternoon, let’s get straight to it, below is what one of the higher resolution forecast models are depicting.  Now this model runs from 7 pm Friday evening through 7 pm Saturday evening.  At this time, we expect precipitation to begin in the form of snow across northwest Indiana between 10 pm and midnight, while precipitation will spread into the western portion of the state by sometime after midnight.  Some of the initial precipitation may not reach the ground.  At this time, we expect areas north of I-70 to remain all snow, but we can not totally rule out a brief period of freezing rain, but I think it’s highly unlikely.  Areas along and just south of I-70 could start off with snow, before mixing in and changing over to freezing rain, before becoming rain by Saturday afternoon.  The southern portions of the state should remain all rain.  As colder air moves in and the area of low pressure gets to its closest point of approach by late Saturday afternoon into the evening, some drier air could move in and bring an end to the snow for the northern counties, while central counties will remain snow, but the southern counties may begin to see a changeover to snow.

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3 KM North American Model from 7 pm EST Friday to 7 pm EST Saturday.  Graphic courtesy of tropicaltidbits.com

Before we get to the snowfall predictions, we are expecting a period of freezing rain, again mainly across areas near or just of I-70.  Some ice accumulations are possible, with the highest between a tenth and a quarter inch just south of Indy.  Less than an tenth of an inch will be possible for the Indy area and points east.  We think that the highest time frame of freezing rain will be during the the late morning into the early afternoon hours.  slide2

Now what everyone is really waiting for, the snowfall potential.  While there’s plenty of disagreement in the models, the placement of the highest snowfall totals, I tried to go with a good blend of all the data, and here we go.  For the northern portion of the state, it will remain all snow, but at the same time, I think as the colder air moves in Saturday afternoon into the evening, the drier air that is normally associated with the colder air will cut off the snow, therefore will cut off overall totals, but going with 3 to 6 inches, with local amounts of up to 8 inches possible.  Like the last storm, it’ll be central Indiana that will see the highest totals, as for now I have 5 to 8 inches, with amounts up to 10 inches possible.  This could change depending on the final track.  South of I-70, is where totals will begin to sharply cut off.  Areas south of Indy, but near and just south of Bloomington, 2 to 3 inches of snow seems possible, but this will be mainly during the afternoon and evening hours on Saturday.  Furthest south, it will be mainly a rain event, but as the colder air moves in, some snowfall will be possible and only 1 to 2 inches will be possible. slide1

Another factor that wasn’t with the last winter storm will be the winds, we expect 20 to 35 mph winds, with gusts of 35 to 45 mph, and blowing of snow will be possible adding in to what will already be hazardous travel.  Like last week, travel will not be recommended on Saturday, especially areas north of I-70. The final graphic below shows the increase of the winds as the storm approaches.  nam3km_mslp_wind_ncus_fh36-60

Finally, in the wake of this winter storm, very cold air will move in on late Saturday and continue into Sunday and Sunday night.  Below is the expected high and low temps Sunday and Sunday night across the state, where subzero temperatures are likely, especially in areas with fresh snowpack.

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To sum everything else, a high confidence in a winter storm impacting Indiana this weekend, high confidence that accumulating snow is likely, especially areas north of I-70.  Lower confidence however in overall snowfall potential as the track of the low will determine where the heaviest snowfall will lie.  Finally, a high confidence in the wake of this winter storm, very cold air will move into the area and will make for a very cold Sunday and Sunday night.  Additional updates will be on the Equinox Weather Facebook page.

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