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Latest on winter storm timeline

Posted at 8:51 AM, Mar 03, 2013
and last updated 2013-03-03 22:09:14-05

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RICHMOND, Va. (WTVR) — The storm we have been discussing for about the past week is currently located over 1500 miles away in the western United States.

The storm track will bring it into our area on Tuesday in the form of rain for much of the area.  A bit of a mix will be possible across northern and northwestern Virginia.  (Click hereto see our previous post on the different possible storm tracks.)

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We will see some periods of moderate to heavy rainfall Tuesday evening and Tuesday night.  There will be a mix across the mountains.blogsnap4

The rain/snow line will slowly track across Virginia during the day Wednesday.  Wet snow will be possible in the Richmond metro area by late afternoon or evening.  Surface temperatures will remain just above freezing, allowing the majority of the snow to melt on impact.  Some accumulation may begin on grassy surfaces.

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The snow will reach near the coast by daybreak on Thursday at the same time it will shutting off across western Virginia.

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A period of moderate to perhaps heavy snowfall will be possible Wednesday evening and night through early Thursday morning.  For areas near metro Richmond and I-95, surface temps will not drop to or below freezing until Wednesday night.

Temperatures in the western part of the state will hit or drop below freezing by Wednesday afternoon or evening, allowing accumulation to begin there.

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By the time the storm exits Thursday morning:

  • The lightest snow accumulations will be areas well east of I-95
  • In metro Richmond and along the I-95 corridor, a light to moderate snow accumulation of at least 2 or 3 inches could occur (with the potential for higher totals).
  • Areas well west of I-95 and near State Highway 15 will see moderate to heavy snow amounts of at least 4 inches (with the potential for higher totals).
  • The heaviest accumulations will fall across the mountains and Interstate 81, where snow totals will surpass 6″ with the potential for more than 10″.

We have reached this forecast by using an ensemble of many computer models over many different time periods in recent days.  So much of this storm is dependent upon the exact storm track, and when surface temperatures hit freezing.

We will definitely update and refine this forecast over the next 48 hours.

Another thing to keep in mind is this storm will produce over 1″ of liquid.  In many areas, a good portion of that will be rain at first.   The ground will turn saturated, with a layer of wet snow & slush on top of it.

As mentioned in our previous post, just a note to those who look at the computer models online.  Remember that one run of one computer model does not mean that solution will occur.  The models are just now getting more data fed into them since the storm is over land.  Many snowfall projections from these models tend not to take in account the ground temps (ie, they are snowFALL amounts, not snow accumulations on the ground).  And, many maps online assume a 10″ of snow to 1″ of water ratio.  With the temps during the storm here being a bit above freezing for a lot of the event, the ratios may be much smaller, perhaps 8″ of snow to 1″ of water.  So, certain maps that are using a 10 to 1 ratio are forecasting too much snow.

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