Snow is arriving in Hoosier state; Will impact Monday commute

UPDATE:  Snow totals are beginning to come in.  Highest totals are between 2.5″ and 3.2″.

Indianapolis is officially up to 3″ as of 8:45 p.m.  That makes this the highest 1-day snow total since January 12, 2019 when 6.9″ fell.  Today ranks as the 2nd most snow for this date since 1871.  3.5″ of snow fell in 1947.  This is also the first 3″ December snow since 2016.

Snow should come to an end by 3 a.m. – 4 a.m. Temperatures will be in upper 20°s to around 30°.  Salt is effective in that range so crews should have a couple hours to get salt on roads for AM commute.

UPDATE: 6:35 p.m. 12/15/19 –

Data pix.

Snow is falling around much of central Indiana.  Expect there to be periods of moderate snow in some of the bands moving through.  Once the band passes, you'll likely get a lull.

Road conditions are going downhill quickly once the snow begins falling.  Several counties around the state are under Travel Watch and Travel Advisory status as of 6:30 p.m. Sunday.

The snow forecast for overnight hasn't changed much from last night.  Still expecting a band of 2" to 4" of snow along and south of the I-70 corridor.

Because of the potential banding of snowing, I think there is potential for a band of 4" to maybe as much as 6" of snow along a very narrow band, maybe only 10-15 miles wide.  It is extremely difficult to determine where the band will set up, if at all, but the map above shows my best guess where it could be.

UPDATE: 3:18 p.m. 12/15/19 - The Storm Prediction Center is highlighting the area along I-70 for potential heavy snowfall rates this afternoon and evening.  There is a band of snow that stretches from St. Louis to north of Evansville. that could produce 1" to 2" per hour snowfall rates.

 

UPDATE: 1:53 p.m. 12/15/19 - Guardian Radar is already detecting a few bands of snow moving in to the southwest portion of central Indiana.

When looking at our weather camera at Fourwinds Lakeside Inn and Marina on the southwest corner of Lake Monroe I am not seeing anything falling from the sky.

Image taken at 1:45 p.m. Sunday.

As mentioned last night in this post, there is a layer of dry air that needs to be over come before the snow can reach the ground.  The radar beam is scanning up around 3,500 feet above the ground.  So it is likely snowing up there but it is evaporating before it gets to the ground.

I expect the column of air to saturate enough to support snow reaching the ground within the next hour for counties in southwest central Indiana.

Computer model projection of radar imagery at 9 p.m. Sunday.

Computer models continue to indicate snow will move north through the state Sunday afternoon and Sunday evening.  Within the snow, there could be bands of moderate to heavy snow.  Exactly where the bands setup, and they may only be 20-30 miles wide, will determine where the heavier snow totals will be.  It still appears a band of 2" to 4" of snow looks possible along, or slightly south, of the I-70 corridor by early Monday morning.

As expected the National Weather Service replaced the Winter Storm Watch with a Winter Weather Advisory for all of central Indiana.  The advisory will be in effect from 5 p.m. Sunday through 7 a.m. Tuesday.

Be sure to keep checking back for further updates.  You can also get more updates by following me on Twitter (@johndissauer).

ORIGINAL POST: 9:37 p.m. 12/14/19

Data pix.

Eyes are trained on two rounds of snow coming to central Indiana for the end of the weekend and beginning of the work week.

A plethora of states are under Winter Storm Warnings, advisories and Winter Storm Watches in anticipation of snow and freezing rain (ice) expected to develop over the next 24-36 hours.

Winter Storm Warnings, Advisories and Winter Storm Watches have been issued in central United States.

A Winter Weather Advisory has been issued for the majority of Indiana. The advisory is in effect from 5 p.m. Sunday and is scheduled to expire at 7 a.m. Tuesday

Clouds will quickly thicken through the day and temperatures will struggle to get out of the mid-30°s Sunday. Precipitation is expected to start moving in to central Indiana by late afternoon. The precipitation type is expected to be all snow Sunday afternoon and in to the night.

Computer model projection of radar/satellite imagery.

While the snow will initially start along the State Road 46 corridor in south-central Indiana, it will eventually begin to spread north. By evening, snow will be falling along and south of a line from Crawfordsville to Richmond.

Computer model projection of radar/satellite imagery.

Snow will continue to fall in to the pre-dawn hours Monday before tapering off.

One thing that could delay the onset of snow reaching the ground is a 4,000 foot layer of drier air above the surface computer models project. Once the column moistens, snow should begin to reach the ground.

By the time most leave for work and school Monday morning, there could be anywhere from nothing up north to as much as 4". The higher amounts should fall along a narrow band, which as of Saturday evening, appears to be along I-70.

Closer inspection of the atmospheric column depicted by computer models shows a "warm" layer of air -- above freezing -- between 2,000 feet and 7,000 feet above the ground mid-Monday morning through Monday evening. That will allow what little precipitation there is to fall as rain.

Once the "warm" layer moves away, we should see a transition to a brief period of freezing rain before going back to all snow Monday night into Tuesday morning.

Monday night into Tuesday morning could see an additional 1" to 3" of snow, taking overall snow totals to 4" to 6" in some spots.

The Sunday night/early Monday morning snow will have an impact on the Monday morning commute. One thing that should help road crews is the snow stopping prior to the morning rush. There could be a window of time where they can lay down salt and even work on plowing roads.

Be sure to check back for updated forecasts over the next 24 to 36 hours. There could still be some fluctuation as to where the heavier band of snow will develop.

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