Winter Storm Outlook

FRIDAY’S SNOW UPDATE

Usually, I update this blog with the ‘the latest model runs’ and the forecast trends.  

As the time frame of the Sunday-Monday storm comes into the range of the higher resolution models, this  potential snow storm is presenting a higher level of variation and  uncertainty with each model addition rather than a clarification of the likely storm snowfall.   Usually, I’d supply some snowfall maps, but it’s a waste of time right now.  Here’s why:

  • First, the European model has backed off of its extreme snowfall amounts for our area. 
  • However, the German ICON model has gotten extreme with its totals. 
  • The GFS has remained somewhat consistent with a mix with rain on Monday. 
  • The Canadian Global and Regional GEMS remains colder with only snow, no rain mix
  • The NAM has come into forecast range and it has a mix with rain/sleet.
  • The SREF forecast has come into range and it’s somewhat higher with snow totals.

Rather than present snowfall maps, I’m going to present maps that capture the current uncertainty—

ICON Statistical Ensemble model showing large variations in the possible position of the coastal low. (Click on image for a larger view.)

 

Here’s the Short Range Ensemble Model (SREF) showing high spread in standard deviation of the surface pressure. High spread suggests high uncertainty in the low pressure position .

SREF ensemble Pressure/standard deviation Monday 10 AM  showing high spread in pressure values in the NE quadrant of the storm.  This could suggest faster movement or uncertainty in position/configuration of the surface low.  Equally uncertain is the high pressure in NY State.   (Click on image for a larger view.) 

 

All this said, here’s the large scale “Snow-Liquid” forecast from the SREF suggesting the statistical areas where highest snowfall is expected—

SREF snow-liquid forecast (correlates with snow totals)  This suggests where the highest snow accumulations will be.   I’m intentionally not putting numbers on the graphic.  (Click on image for a larger view.)

 

So, the takeaway is that we’re getting several inches of snow, starting Sunday afternoon and running through Monday; high uncertainty about specific snow totals in any one specific area.   Sometimes, the best forecast information is to indicate what we don’t know.

I’ll take another attempt at specific snow forecast this evening, when we have today’s model runs to review.   Stay tuned.