Weather models for the last 4 or 5 days across the board have been developing a signature blocking pattern in the North Atlantic. The differences lie in how strong a block and each model has its own ideas regarding this. Ultimately it will be the strength of such a block that will determine how cold it will be (or won't be). Given the unstable nature of blocking patterns model volatility will continue to run rather high from day to day and from run to run. Blocking patterns have been responsible for some big storms in the past however the block alone is not a guarantee of any storm weak or strong. There are other factors in the atmosphere that are in play as well and the odds of all those factors coming together for one particular area are usually pretty low and are not going to be shown very well in the long range.
The block appears over the next few days and begins to strengthen as the week progresses. This forces troughing in the east and we do have a weak system that is rotating in the flow for Thursday night into Friday morning. There really isn't much room for this system to develop and only precipitation is forecast from this. It should be cold enough for it to be snow and it looks like it could be a coating to a couple of inches for somebody from the Northern Ohio Valley to Southern New England.
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Once this system moves out models diverge somewhat because each model has a different idea of how the block evolves over time. The GFS model and Canadian model both show troughs in the east with the higher pressures over Greenland but again strength of the block dictates the depth of the trough...read more at http://www.meteorologistjoecioffi.com/index.php/2017/02/26/march-lion-blocking-pattern-developing/